Understanding Surge Protector Specs for the Computer Age

[Tom.G]

And I understand that if I add a type 3 spd at equipment, the impedance of the 10 meter distance is what segregate it such that the SPD type 3 at equipment would only see the 1200 VPR output of the spd type 2 at breaker and not the full high voltage surge from the strike? If it sees only the 1200 VPR at the breaker then adding type 3 could bring it down to normal 220 volts (or 220.001 volts) VPR at equipment.

You've got 99% of it right.
The type 3 at the equipment will bring the surge down to whatever its protection voltage is, and the type 3 SPD can have a lower energy rating than the type 2 in the breaker box.

ADDENDUM:
Hmm, we were typing at the same time. Your most recent post (#50) is for the case where you have the SPD in the breaker box but do NOT have one at the equipment to be protected. That's another reason to have an SPD as close to the equipment as possible, it eliminates those reflections and possible voltage doubling.

If needed, I'll post a sketch tomorrow (or maybe later today).

Cheers,
Tom

 

[kiki_danc]

You've got 99% of it right.
The type 3 at the equipment will bring the surge down to whatever its protection voltage is, and the type 3 SPD can have a lower energy rating than the type 2 in the breaker box.

ADDENDUM:
Hmm, we were typing at the same time. Your most recent post (#50) is for the case where you have the SPD in the breaker box but do NOT have one at the equipment to be protected. That's another reason to have an SPD as close to the equipment as possible, it eliminates those reflections and possible voltage doubling.

If needed, I'll post a sketch tomorrow (or maybe later today).

Cheers,
Tom

The following SPD type 3 is being offered to me:

If it can bring the 1200 Volts VPR in the Spd type 2 in the breaker to 220 volts in the equipment.. then I'd purchase it asap even if it's more expensive than the type 3. Also it's installed as series.. this is ok?

But do you know how UL computes the 10 meters length to be used as impedance to lower the voltage in the type 3? The supplier doesn't know. My existing length between breaker to equipment is just 5 meters. If you can show 10 meters is necessary. Then I'll add 5 meters by looping it in the side to satisfy the UL requirements. Thanks.

 

[Tom.G]

If it can bring the 1200 Volts VPR in the Spd type 2 in the breaker to 220 volts in the equipment.. then I'd purchase it asap even if it's more expensive than the type 3. Also it's installed as series.. this is ok?

The datasheet you posted says VPR <1KV and it starts to clamp around 370V, probably as low as you can find for a 220/277V rated device. Notice that the maximum continuous power line voltage is 320V.

Series is OK for this one. As shown in the schematic, internally the SPD components are installed across the power line. Because it has exposed metal connected to the power line, this device is designed to be mounted in an electrical box or in the protected equipment itself. Just be sure it is installed close to the equipment you want to protect.

But do you know how UL computes the 10 meters length to be used as impedance to lower the voltage in the type 3?

No I don't know how they came up with 10 meters but that is one of the requirements to meet Type 3 SPD standards in UL-1449. Here is the link to the UL page which has a short description, you can research further from there. https://standardscatalog.ul.com/standards/en/standard_1449

If you are rich they will sell you a copy of the complete standard starting at USD $716. You may be able to find a lower cost copy of whatever standard is used in your country. Sometimes a Google search will turn up free copies of a standard.

Cheers,
Tom

 

[kiki_danc]

The datasheet you posted says VPR <1KV and it starts to clamp around 370V, probably as low as you can find for a 220/277V rated device. Notice that the maximum continuous power line voltage is 320V.

Series is OK for this one. As shown in the schematic, internally the SPD components are installed across the power line. Because it has exposed metal connected to the power line, this device is designed to be mounted in an electrical box or in the protected equipment itself. Just be sure it is installed close to the equipment you want to protect.No I don't know how they came up with 10 meters but that is one of the requirements to meet Type 3 SPD standards in UL-1449. Here is the link to the UL page which has a short description, you can research further from there. https://standardscatalog.ul.com/standards/en/standard_1449

If you are rich they will sell you a copy of the complete standard starting at USD $716. You may be able to find a lower cost copy of whatever standard is used in your country. Sometimes a Google search will turn up free copies of a standard.

Cheers,
Tom

This is the continuation of the specs that is cut due to screen size limit:

As you can see, it's Approval and Certification is only CE.. Not UL.. my installed Prosurge model has UL, KEMA certification. Do you think surge protector with only CE approval and not UL is not fully tested? Because I only heard about UL 1449 4th Edition where they change the name of TVSS to SPD. The CE approval process or body doesn't seem to involve SPD. What do you make of this? And do you think UL tested every device that has UL approval?

Another thing. For main circuit breaker.. do you think 50kA Imax is enough? Can surge discharges from outside occur more than 50kA sometimes? If so, then I'll get a 100kA to be put in the main breaker and the 50kA transferred to my equipment as the above type is only 25kA and if I'm hit with surges above 50kA then both would get fried.

 

[Tom.G]

Do you think surge protector with only CE approval and not UL is not fully tested?

Below is from the last paragraph of: https://ec.europa.eu/growth/single-market/ce-marking_en
Please note that a CE marking does not indicate that a product have been approved as safe by the EU or by another authority.

The complete KEMA certifications is the GOLD certificate where tests are performed in the KEMA labs compliance with standards and documentation. Other levels are SILVER and GREY, which are not as complete.
Here is an excerpt from the KEMA website. (https://www.dnvgl.com/energy/laboratories/reports.html)
Gold: KEMA Type Test Certificate
A KEMA Type Test Certificate is issued when all tests are carried out successfully at KEMA Laboratories in accordance with a recognized standard the technical drawings have been verified and a visual inspection has been carried out. To receive this certificate, the equipment tested must fulfill all the requirements of the standard and the relevant ratings assigned by the manufacturer.

Underwriters Laboratories (UL) performs tests in their own labs and addresses mainly safety issues. UL was started by the insurance companies to decrease their losses from poor, unsafe products.

And do you think UL tested every device that has UL approval?

UL tests products for compliance to the UL safety specifications, this is done on either a prototype or on "typical" products taken from a production line. If it passes, the product is assigned a number and the manufacturer gets the right to advertise that and to affix a UL label to the product. UL does not continuously inspect products being manufactured, and I seriously doubt that any of the other agency would either.

do you think 50kA Imax is enough?

I have no idea. Ask your power company or the agency that regulates your power company, or maybe the manfacturer of your circuit breakers.

You seem to be looking for absolute protection from power line surges. There is no such thing. A few years ago a tall flagpole about 80feet (25m) away was struck by lightning. My computer equipment was on the second floor protected by SPDs and a battery powered Uninterruptable Power Supply (UPS). Most of the equipment survived, but the printer died. Apparently the data cable between computer and printer had enough voltage directly induced in it from the lightning strike to damage the printer.

The closest you can get to absolute protection is your own generator (maybe with battery backup) inside a well grounded metallic enclosure that also contains you protected equipment, no wires entering or exiting to the outside, and Lightning rods around it. That will work until the control circuit on the generator fails. (Data transmission to/from the outside with optical cables.)

The KEMA and CE info above was found with simple Google searches that you can do, as was some of the earlier UL info. I will start suggesting you do that for your future easily found questions.

Cheers,
Tom

 

[kiki_danc]

Below is from the last paragraph of: https://ec.europa.eu/growth/single-market/ce-marking_en
Please note that a CE marking does not indicate that a product have been approved as safe by the EU or by another authority.

The complete KEMA certifications is the GOLD certificate where tests are performed in the KEMA labs compliance with standards and documentation. Other levels are SILVER and GREY, which are not as complete.
Here is an excerpt from the KEMA website. (https://www.dnvgl.com/energy/laboratories/reports.html)
Gold: KEMA Type Test Certificate
A KEMA Type Test Certificate is issued when all tests are carried out successfully at KEMA Laboratories in accordance with a recognized standard the technical drawings have been verified and a visual inspection has been carried out. To receive this certificate, the equipment tested must fulfill all the requirements of the standard and the relevant ratings assigned by the manufacturer.

Underwriters Laboratories (UL) performs tests in their own labs and addresses mainly safety issues. UL was started by the insurance companies to decrease their losses from poor, unsafe products.UL tests products for compliance to the UL safety specifications, this is done on either a prototype or on "typical" products taken from a production line. If it passes, the product is assigned a number and the manufacturer gets the right to advertise that and to affix a UL label to the product. UL does not continuously inspect products being manufactured, and I seriously doubt that any of the other agency would either.I have no idea. Ask your power company or the agency that regulates your power company, or maybe the manfacturer of your circuit breakers.

You seem to be looking for absolute protection from power line surges. There is no such thing. A few years ago a tall flagpole about 80feet (25m) away was struck by lightning. My computer equipment was on the second floor protected by SPDs and a battery powered Uninterruptable Power Supply (UPS). Most of the equipment survived, but the printer died. Apparently the data cable between computer and printer had enough voltage directly induced in it from the lightning strike to damage the printer.

The closest you can get to absolute protection is your own generator (maybe with battery backup) inside a well grounded metallic enclosure that also contains you protected equipment, no wires entering or exiting to the outside, and Lightning rods around it. That will work until the control circuit on the generator fails. (Data transmission to/from the outside with optical cables.)

The KEMA and CE info above was found with simple Google searches that you can do, as was some of the earlier UL info. I will start suggesting you do that for your future easily found questions.

Cheers,
Tom

Many thanks (to Rive too who introduced me to the world of SPDs).

Last question (and to wrap up the tread).

I will look for one with UL approved so at least the specs were not just made up. But I'm concerned about the Live, Neutral and Ground thing. In my place. My single phase 220 volts uses Live and Neutral only (but since Live & Neutral alternate back and forth.. it can be either), then ground is separate. In SPD products sometimes there is this included protection mode like in:

You can see there is this line "Protection Mode: L-G, L-N, N-G". In the Prosurge product I bought (with specs listed again below), there is no mentioned protection mode.. do you think it protects L-G, L-N, N-G as well?

and last question: The 25kA and 100 kA Prosurge is not UL approved.. only the 50kA is UL approved. If I buy another 50kA as my type 3.. do you think it can also decrease the voltage to 220 volts.. Let's say you have 3 SPS with 25kA, 50kA, 100kA.. if the input voltage is 1200 volts (say you make all of them as type 3). would they all clamp it down to 220 volts? Or does this only work for lower surge current product like 15kA where it can successfully lower it down? Also you said the Prosurge product you commented yesterday can clamp above 370Vac. that is because of the Temporary Overvoltage TOV rating.. but for other specs (many products has nothing of it listed) that has none of the Temp Voltage TOV rating listed and just the MCOV spec of say 320 volts.. do you think the clamping voltage is 320 volts?

Many thanks!

 

[kiki_danc]

Many thanks (to Rive too who introduced me to the world of SPDs).

Last question (and to wrap up the tread).

I will look for one with UL approved so at least the specs were not just made up. But I'm concerned about the Live, Neutral and Ground thing. In my place. My single phase 220 volts uses Live and Neutral only (but since Live & Neutral alternate back and forth.. it can be either), then ground is separate. In SPD products sometimes there is this included protection mode like in:
View attachment 231281

You can see there is this line "Protection Mode: L-G, L-N, N-G". In the Prosurge product I bought (with specs listed again below), there is no mentioned protection mode.. do you think it protects L-G, L-N, N-G as well?

View attachment 231286

and last question: The 25kA and 100 kA Prosurge is not UL approved.. only the 50kA is UL approved. If I buy another 50kA as my type 3.. do you think it can also decrease the voltage to 220 volts.. Let's say you have 3 SPS with 25kA, 50kA, 100kA.. if the input voltage is 1200 volts (say you make all of them as type 3). would they all clamp it down to 220 volts? Or does this only work for lower surge current product like 15kA where it can successfully lower it down? Also you said the Prosurge product you commented yesterday can clamp above 370Vac. that is because of the Temporary Overvoltage TOV rating.. but for other specs (many products has nothing of it listed) that has none of the Temp Voltage TOV rating listed and just the MCOV spec of say 320 volts.. do you think the clamping voltage is 320 volts?

Many thanks!

Here is a challenging problem whose solution can't be found in any simple or moderate (or even advanced) google search.

My ac power uses half phase, we don't have any neutral. So I wonder if my existing prosurge parallel shunt mode protection is useless and the supplier just want to grab my money. I read in the following that parallel SPD may really be useless (I don't know how to apply it in my case) https://zerosurge.com/normal-mode-v-common-mode/

"When researching methods of surge protection, one concept that you may find is the idea of surges or noise that can follow one of two paths:

The normal path (i.e. Normal or Differential Mode) along the Line (Hot) to Neutral circuit

The common path (i.e. Common Mode) which is a path connecting the Line to Ground or the Neutral to Ground.

The US Government1 defines the operation of surge suppressors in one of two modes:

Mode 1: Normal Mode only (Line to Neutral suppression)

Mode 2: All Modes (Both Common and Normal Modes)

Zero Surge Series Mode Filter Technology operates on Normal Mode surges only. Common Mode protection is not required to protect equipment from surge damage. Therefore, looking for a product that claims “All Modes Protection” or “Mode 2 Protection” is not required and actually can cause more harm than good.

Mode 2 products (all modes) have several side effects which can degrade and endanger your system. Two of these modes (L-G and N-G) divert surges to the ground wire, supposedly protecting from “Common Mode” surges. But these “Common Mode” surges diverted to the ground wire can have disastrous results.

The Neutral line and Ground line are bonded at the service entrance which prevents external Common Mode surges.

>Common Mode surges exist only at extremely low energy levels well within a building (0.17 Joule for worst case surges according to American National Standard ANSI C62.41 — formerly IEEE 587, page 47)2,3.

Modern equipment is inherently immune to Common Mode surges.

By sending surges to the ground line, the voltage rise on the ground can disrupt audio, video, data and communications signals and also damage interconnected equipment.4"

What do you make of it Tom G? or other familiar with this? If this is too difficult question, please refer me to electrical engineering forum so I can discuss with them because I can't find the answer in google search.. Thanks.

 

[kiki_danc]

Here is a challenging problem whose solution can't be found in any simple or moderate (or even advanced) google search.

My ac power uses half phase, we don't have any neutral. So I wonder if my existing prosurge parallel shunt mode protection is useless and the supplier just want to grab my money. I read in the following that parallel SPD may really be useless (I don't know how to apply it in my case) https://zerosurge.com/normal-mode-v-common-mode/

"When researching methods of surge protection, one concept that you may find is the idea of surges or noise that can follow one of two paths:
View attachment 231318The normal path (i.e. Normal or Differential Mode) along the Line (Hot) to Neutral circuit
View attachment 231319The common path (i.e. Common Mode) which is a path connecting the Line to Ground or the Neutral to Ground.

The US Government1 defines the operation of surge suppressors in one of two modes:

View attachment 231320Mode 1: Normal Mode only (Line to Neutral suppression)
View attachment 231321Mode 2: All Modes (Both Common and Normal Modes)

Zero Surge Series Mode Filter Technology operates on Normal Mode surges only. Common Mode protection is not required to protect equipment from surge damage. Therefore, looking for a product that claims “All Modes Protection” or “Mode 2 Protection” is not required and actually can cause more harm than good.

Mode 2 products (all modes) have several side effects which can degrade and endanger your system. Two of these modes (L-G and N-G) divert surges to the ground wire, supposedly protecting from “Common Mode” surges. But these “Common Mode” surges diverted to the ground wire can have disastrous results.

The Neutral line and Ground line are bonded at the service entrance which prevents external Common Mode surges.

>Common Mode surges exist only at extremely low energy levels well within a building (0.17 Joule for worst case surges according to American National Standard ANSI C62.41 — formerly IEEE 587, page 47)2,3.
View attachment 231322Modern equipment is inherently immune to Common Mode surges.
View attachment 231323By sending surges to the ground line, the voltage rise on the ground can disrupt audio, video, data and communications signals and also damage interconnected equipment.4"

What do you make of it Tom G? or other familiar with this? If this is too difficult question, please refer me to electrical engineering forum so I can discuss with them because I can't find the answer in google search.. Thanks.

A while ago. I let electrician measure the voltage between one of the lines and ground (see pic illustration). It's 120 volts.. whereas if he measures the 2 wires at breaker.. It's 240 volts.. therefore my ac power is really line to line half phase. Would it really work by installing SPD type 2 that shunt it to ground? If there is a surge in either of the 120 volts wire, would it shunt it to ground or would it be line to line that needs to be engaged? Isn't it if there is surge at the line to line.. you need protection at line to line? My electrician doesn't have any idea and my suppliers are not telling me straight (maybe because they want to sell their overstock). So if anyone of you have a clue, please share so I can decide whether to replace the spd type 2 with full mode protection (I'd like to understand what additional would I gain from this when ultimately it shunts to ground). Thanks.

 

[Tom.G]

>Common Mode surges exist only at extremely low energy levels well within a building (0.17 Joule for worst case surges according to American National Standard ANSI C62.41 — formerly IEEE 587, page 47)2,3.

Modern equipment is inherently immune to Common Mode surges.

By sending surges to the ground line, the voltage rise on the ground can disrupt audio, video, data and communications signals and also damage interconnected equipment.4"

What do you make of it Tom G? or other familiar with this?

Please supply a link where these statements can be found. Without seeing the context they are in, we can not evaluate their applicability. In particular I am suspicious of apparently conflicting statements in the above:

1. Common Mode surges...at extremely low energy
2. Modern equipment is inherently immune to Common Mode surges.
   
3. sending surges to the ground line, the voltage rise on the ground can disrupt...

Lets take these in reverse order. If the Ground line voltage rises, with a 220V supply that is a Common Mode voltage as seen by the equipment.
But then there is the statement that "Modern equipment is inherently immune to Common Mode surges." So how is this a problem?
And it starts by saying Common Mode surges...at extremely low energy. So how can they be a problem if the equipment is inherently immune?

If there is a surge in either of the 120 volts wire, would it shunt it to ground or would it be line to line that needs to be engaged? Isn't it if there is surge at the line to line.. you need protection at line to line?

Per the photo in the same post, a surge on either 120 wire will be shunted to ground. If there is a common mode surge, meaning that if each 120V line has a surge, then each will be shunted to ground at the same time.

So far you have been stating that the power supply is connected to 220V (240V) supply, yet your photo of the breaker box clearly shows the availability of 120V. With your concern of exceeding the 300V maximum of the power supply, the obvious approach is to connect the power supply to 120V and use a 120V SPD. I suspect the voltage at your wall outlets actually has 120V available, can you or someone else measure this?

 

[kiki_danc]

Please supply a link where these statements can be found. Without seeing the context they are in, we can not evaluate their applicability. In particular I am suspicious of apparently conflicting statements in the above:

Here is the link I also shared in the same message https://zerosurge.com/normal-mode-v-common-mode/

1. Common Mode surges...at extremely low energy
2. Modern equipment is inherently immune to Common Mode surges.
   
3. sending surges to the ground line, the voltage rise on the ground can disrupt...

Lets take these in reverse order. If the Ground line voltage rises, with a 220V supply that is a Common Mode voltage as seen by the equipment.
But then there is the statement that "Modern equipment is inherently immune to Common Mode surges." So how is this a problem?
And it starts by saying Common Mode surges...at extremely low energy. So how can they be a problem if the equipment is inherently immune?Per the photo in the same post, a surge on either 120 wire will be shunted to ground. If there is a common mode surge, meaning that if each 120V line has a surge, then each will be shunted to ground at the same time.

So far you have been stating that the power supply is connected to 220V (240V) supply, yet your photo of the breaker box clearly shows the availability of 120V. With your concern of exceeding the 300V maximum of the power supply, the obvious approach is to connect the power supply to 120V and use a 120V SPD. I suspect the voltage at your wall outlets actually has 120V available, can you or someone else measure this?

After discussing with the electrician.. here are the complete facts.

The building service entrance is 3 phase with delta transformer... per phase is 120 volts.. but we never have any 120 volts outlets because 100% of our equipments are all 220 volts.. therefore my 220 volts in the outlets came from the line 1 and line 2 (or line 2 and 3 or 1 and 3) of the 3 phase.. in another floor.. the breaker is 3 phase. The one in the picture is admin breaker supplying only lights, cctv and security, hence only single phase needed and the design just tapped the phase 1 and 2 of the 3 phase service entrance power. With all these information.. my Spd type 2 that is line to ground won't be engaged at all because I don't have any equipments in the outlets that is 110 volts, right? If you agree, then I'll remove the existing SPDs and return them to supplier and buy a line to line SPD or delta SPD instead. Thanks.

 

[kiki_danc]

Here is the link I also shared in the same message https://zerosurge.com/normal-mode-v-common-mode/
After discussing with the electrician.. here are the complete facts.

The building service entrance is 3 phase with delta transformer... per phase is 120 volts.. but we never have any 120 volts outlets because 100% of our equipments are all 220 volts.. therefore my 220 volts in the outlets came from the line 1 and line 2 (or line 2 and 3 or 1 and 3) of the 3 phase.. in another floor.. the breaker is 3 phase. The one in the picture is admin breaker supplying only lights, cctv and security, hence only single phase needed and the design just tapped the phase 1 and 2 of the 3 phase service entrance power. With all these information.. my Spd type 2 that is line to ground won't be engaged at all because I don't have any equipments in the outlets that is 110 volts, right? If you agree, then I'll remove the existing SPDs and return them to supplier and buy a line to line SPD or delta SPD instead. Thanks.

Here's the breakers in my service entrance:

The front silver thing is the ground lugs. We don't have any neutral. If you will measure the voltage in any of the lines to the ground or even the enclosure, it's 120 volts.. but we never use 120 volts because all our equipments are 240 volts.. the one in the middle is the admin which connects to the panel you saw earlier. Therefore what I need are line to line SPD protecting 2 phases and not 1 phase to ground which is not utilized, right?? In the event there is surge in the line to line (phase 1 to phase 2), would it separately shunt to ground without any equipments actually connected to any phase and ground (or 110 volts we never used?)

 

[Tom.G]

OK, your last post added much missing information and cleared up much confusion. (Whew!)

I see two relatively easy approaches:

1. Use a Control Transformer to feed the power supply, 240V primary, 120V secondary
2. If it is legal with your particular wiring where you are, tap 120V from one leg and use the common Ground as Neutral.

Either way, you can then use a 120V SPD at the power supply. This addresses your concern about the 300V input limit of the power supply.

With option 1., if you use an appropriately sized (small enough) Control Transformer you can use a type 3 SPD and you do not need the 10m wire length before the SPD, the transformer impedance will be more than adequate. You will still need a Ground connection wire for the SPD (or use the conduit if it's legal there). That's because high voltage spikes can get thru a transformer due to the capacitance between primary and secondary.

If you use option 2. above, you will need a type 2 SPD.

You could ask your power company or the city electrical inspector about the legality of option 2.

Cheers,
Tom

p.s. Please let us know how this all works out. Many people here have put time and effort into this and we are always curious.

 

[kiki_danc]

OK, your last post added much missing information and cleared up much confusion. (Whew!)

I see two relatively easy approaches:

1. Use a Control Transformer to feed the power supply, 240V primary, 120V secondary
2. If it is legal with your particular wiring where you are, tap 120V from one leg and use the common Ground as Neutral.

Either way, you can then use a 120V SPD at the power supply. This addresses your concern about the 300V input limit of the power supply.

With option 1., if you use an appropriately sized (small enough) Control Transformer you can use a type 3 SPD and you do not need the 10m wire length before the SPD, the transformer impedance will be more than adequate. You will still need a Ground connection wire for the SPD (or use the conduit if it's legal there). That's because high voltage spikes can get thru a transformer due to the capacitance between primary and secondary.

If you use option 2. above, you will need a type 2 SPD.

You could ask your power company or the city electrical inspector about the legality of option 2.

Cheers,
Tom

p.s. Please let us know how this all works out. Many people here have put time and effort into this and we are always curious.

In your post. You were assuming we have 120 volts equipments or power supplies. We never have this. If we order items from the US which uses 120 volts. We always use up-transformer to convert the 120 volts to 240 volts because all our gadgets and stuff uses 240 volts.. therefore what would be the use of 120 volts.

But I realized you were right that in my current installation, the 320 Vac SPD is too much for the 120 volts phase to ground that we never use or a mismatched.

Supposed I don't want to use any 120 volts which we don't use. And reviewing the delta configuration:

If I'll use the ac power configuration as originally given.. that is using phase A and B to power the computer producing 240 volts. And there is a surge, would the SPD installed in phase A to ground suppress the wires connecting phase A and B? I just want a definite yes or no. If no, then I'll look for a line to line MOV and SPD and either return the installed SPD or sell it since it doesn't do its intended function at all. Thanks so much.

 

[Tom.G]

would the SPD installed in phase A to ground suppress the wires connecting phase A and B? I just want a definite yes or no.

No.
The power supply you specified in post #1

I have a power supply model Mean Well RS-50-24

is universal input voltage capable over the input range of 88V to 264V so it will work with 120V input.

 

[kiki_danc]

No.

Thanks for this. I'll try to get a Line to Line SPD instead. But 3 phase SPD is very expensive at more than $1000.

The power supply you specified in post #1

is universal input voltage capable over the input range of 88V to 264V so it will work with 120V input.

Oh.. the meanwell power suppy. I finally understood what you were saying or implying in your last message. But if I tap the 120 volts and the ground.. won't the ground attract unwanted and unpredictable voltage sfrom either surges from other buildings or lightning strikes or etc (since ground is connected to all the enclosures and power dirt source in the entire city). I wonder if this is advisible even if city hall would permit it.

Lastly. I found out I can no longer return the 320Vac type 2 SPD. If I'd use this for the above idea of using 120 volts from line to ground.. I wonder if there is some adverse behavior from using SPD of much higher voltage rating (320 Vac) for power source that is much lower (120 volts)? I can't find any answer of this online because no many are foolish to use much higher SPD voltage rating but I'm stuck with it so asking this.

Thank you so much for your thoughts and advices.. 5 stars to you.. i'd "like" every post of yours lol...

 

[Tom.G]

I wonder if there is some adverse behavior from using SPD of much higher voltage rating (320 Vac) for power source that is much lower (120 volts)?

The 'adverse behavior' is the higher clamping voltage, which you cited as a problem earlier.

Thank you so much for your thoughts and advices.. 5 stars to you.. i'd "like" every post of yours lol...

A few of the the better ones in this thread would be adequate.

 

[kiki_danc]

The 'adverse behavior' is the higher clamping voltage, which you cited as a problem earlier.

A few of the the better ones in this thread would be adequate.

I got all useful information now to make sure the supplier would refund the SPD to be removed (to be replaced with a line to line spd).. if he won't refund and he is the supplier of it direct from Prosurge in china.. then I'd give technical details to the china head that the supplier doesn't first check my power system before installing it so my supplier would indeed refund it.

Thanks to you again and to Rive (and others who helped).

 

[kiki_danc]

Update. I am debating with the Prosurge supplier. He kept telling me he installed TVSS for a decade and sure an SPD intended for line to ground can work if the load is line to line... again consider the illustration:

If my computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground.. why wouldn't it work? There is a potential for the phase and ground.. so won't the SPD be engaged even if the load is not connected to ground. Case in point.. if you touch the phase to ground, the connection would explode.. so there is great potential between the phase and ground.. so if an SPD is installed between phase and ground.. won't it be activated even if the surge occurs at Phase A and B? Please give arguments what is the case at hand just so in case the supplier could be right in some ways. Thanks (this is the last question! promised.. lol)

 

[kiki_danc]

Update. I am debating with the Prosurge supplier. He kept telling me he installed TVSS for a decade and sure an SPD intended for line to ground can work if the load is line to line... again consider the illustration:

View attachment 231338

If my computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground.. why wouldn't it work?

To clarify. I mean if there are two SPDs intended for phase A to ground and phase B to ground.. won't they shunt a phase A and B load and eliminate the surge between phase A and B?? I omitted the phase B to ground in my last question which you answered "No".

There is a potential for the phase and ground.. so won't the SPD be engaged even if the load is not connected to ground. Case in point.. if you touch the phase to ground, the connection would explode.. so there is great potential between the phase and ground.. so if an SPD is installed between phase and ground.. won't it be activated even if the surge occurs at Phase A and B? Please give arguments what is the case at hand just so in case the supplier could be right in some ways. Thanks (this is the last question! promised.. lol)

 

[kiki_danc]

To clarify. I mean if there are two SPDs intended for phase A to ground and phase B to ground.. won't they shunt a phase A and B load and eliminate the surge between phase A and B?? I omitted the phase B to ground in my last question which you answered "No".

I think it can work in the sense of the line to line protection mode being protected by the series combination of the line-to-ground and ground-to-line modes. But why haven't you considered this? And what would be the behavior of this series mode. I only know the MCOV voltage would add up becoming 320V+320V=640 V (and clamping voltage would further increase). But would the two SPDs in series to the line to line become heating elements (to suppress the surge) or would they still shunt the voltages to the ground? I think this might be what the supplier was trying to consider. He couldn't explain the details. And I can't find the reference about this in google. So hope to get your opinion of the scenerio. Thanks again.

 

[Tom.G]

the MCOV voltage would add up becoming 320V+320V=640 V (and clamping voltage would further increase).

Yes, that would be the case; you could get twice the expected voltage line-to-line if the SPDs were rated at the line-to-line voltage and were connected line-to-ground. Also, your earlier posts seemed to indicate that the 240V 3-phase was not referenced to ground (which I found rather strange at the time and was cleared up in your post #61.) Since in reality you have 120V 2-phase, 120V SPD on each line would work. There are also 120v/240v SPDs for exactly that situation. But that would exceed the 300V limitation on the power supply input voltage. The only way to address the 300V limitation is to supply 120V to the power supply.

But why haven't you considered this?

Because that was not the question you asked. You asked in post #63 "computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground."

As a side comment, I am not at all surprised that your attempt to return the already installed SPDs was rejected. The vendor has no way of knowing or testing if the have been damaged by a surge. Would you willingly buy a used protective device at full price knowing that it is in unknown condition? At least here in the USA, electrical and electronic components that have been installed are not returnable, for not only that reason but the vendor could be liable for any subsequent damage.

Cheers,
Tom

 

[kiki_danc]

Yes, that would be the case; you could get twice the expected voltage line-to-line if the SPDs were rated at the line-to-line voltage and were connected line-to-ground. Also, your earlier posts seemed to indicate that the 240V 3-phase was not referenced to ground (which I found rather strange at the time and was cleared up in your post #61.) Since in reality you have 120V 2-phase, 120V SPD on each line would work. There are also 120v/240v SPDs for exactly that situation. But that would exceed the 300V limitation on the power supply input voltage. The only way to address the 300V limitation is to supply 120V to the power supply.

Because that was not the question you asked. You asked in post #63 "computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground."

As a side comment, I am not at all surprised that your attempt to return the already installed SPDs was rejected. The vendor has no way of knowing or testing if the have been damaged by a surge. Would you willingly buy a used protective device at full price knowing that it is in unknown condition? At least here in the USA, electrical and electronic components that have been installed are not returnable, for not only that reason but the vendor could be liable for any subsequent damage.

Cheers,
Tom

Oh I haven't thought of it that supplier won't accept the product for return because it may suffer a bit of surge damage already.

Anyway you haven't answered this question:

So the above will work only at increased clamping voltage. Ok. But I was asking if the surge would be dissipated by the current going to the ground or the MOV element just heating up... what do you think?

 

[kiki_danc]

Here's an interesting experiment in the paper at http://www.surgesuppression.com/ima...licationofSurgeSuppressionRevDate10202005.pdf

Power was applied to Phase A and B and thermometer was used to measure the temperature of the MOV when surge was introduced (details in the paper above).

Based on the much higher temperature rise in the discrete line-to-line MOV, the discrete line-to-line MOV absorbs a much larger portion of the surge current and energy than the combination of the two line-to-neutral paths.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground MOVs (instead of just the 1 discrete line to line MOV).. is the current of the 2 element series not shunted to neutral? I assume neutral is same as ground.

If the neutral were made ground.. would the results be the same?

And lastly if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Knowing the answers above would wrap up my questions about SPD and end up this thread once and for all. Lol.

 

[kiki_danc]

Here's an interesting experiment in the paper at http://www.surgesuppression.com/images/DotNetSite/TechPapers/ModesofProtectionwithinElectricalSystemsforApplicationofSurgeSuppressionRevDate10202005.pdf

View attachment 231382

View attachment 231383Power was applied to Phase A and B and thermometer was used to measure the temperature of the MOV when surge was introduced (details in the paper above).

Based on the much higher temperature rise in the discrete line-to-line MOV, the discrete line-to-line MOV absorbs a much larger portion of the surge current and energy than the combination of the two line-to-neutral paths.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground MOVs (instead of just the 1 discrete line to line MOV).. is the current of the 2 element series not shunted to neutral? I assume neutral is same as ground.

If the neutral were made ground.. would the results be the same?

And lastly if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Knowing the answers above would wrap up my questions about SPD and end up this thread once and for all. Lol.

Since MOV can be used between line to line as indicated in the paper above.. I wonder what would happen in the following if one of my 320 Vac MCOVs (instead of two) were put between the 120 volts line:

Of course I won't try it (I'm not crazy to experiment). Just want to know what theoretically would happen.. would it explode? Or work in a while then shuts down? etc.

 

[Tom.G]

This is in response to your post #72. I must have forgotten to click the POST REPLY button before I went off-line for a while.

Another case of insufficient information or under specified condition. You show a 3-phase transformer without a Ground or Common connection, in an earlier post you specified 3-phase 240V with 120V to a Common. Here the 3 lines are labeled 120Vac but your earlier posts stated the transformer windings as 240V. When measuring 120Vac on this diagram where is the other voltmeter lead placed?

 

[kiki_danc]

The other voltmeter lead is placed in the ground lugs of the panel which is simply connected to the Earth or soil. Our power company doesn't have separate ground or neutral. My service entrance has only 3 wires (3 phase) coming to the building.. we provide our own ground by sticking it to earth. I'm sure of this because I inquired from the power company years ago.

Anyway, the 120 volt thing has opened the floodgates in that I can now access all of amazon products which are based on 120 volts. Before I had difficulty finding supplier.. and only found one prosurge distributor locally. Now I can buy for example $69 Prosurge at amazon like https://www.amazon.com/dp/B012IR9Q2K/?tag=pfamazon01-20

My supplier sold the 240 volts version at more than $100. At amazon the 120 volts same specs is only $69. Now I am curious about something. In the United States.. you have Line to Neutral of 120 volts.. and you use it to power your appliances.. if you have 3 phase there.. is it also 120 volts per phase.. meaning if you connect phase to phase.. then it's also 240 volts? I wonder if the US and my place has same power transformers and only the tapping differs. And does it matter if the ground is provided in the transformer or in the soil. Our power company simply doing cutting costs by saving the ground in the transformer and we need to provide ourselves.

I'm asking you this since you can describe it from the perspective of what I mentioned in this thread. Also I think I'd better get a line to line SPD. I saw this at amazon. https://www.amazon.com/dp/B0052NKYC4/?tag=pfamazon01-20
Siemens TPS3A03050 120/240 Type 1 Split Phase Surge Protective Device Lightning Arrester Replacement

In the US. Is there a 120/240 split phase power system? Is it the same as the Delta with 120 volts per phase in my place (and 240 volts line to line)?

I promise this is the last level of inquiry as I don't want to get so much of your time. And as a way of saying thanks.. I can give you my 240 volts prosurge if you need it.. lol
​

 

[Tom.G]

Reference your post #73.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground

Remember that the MOV's act like a resistor when they conduct, their voltages rise as their current increases. The 300V sum of the 2 MOV voltages is close to the 320V of the line-to-line MOV. With the voltages being so close they are sharing the current.

is the current of the 2 element series not shunted to neutral?

The current DIFFERENCE between the 2 elements would typically be shunted to Neutral (which is usually Ground). For instance if one of the MOV's conducted 100A and the other 120A, then 20A would typically flow thru the Neutral lead. There is not enough detail of the test setup nor is it known to me if your Neutral/Common is indeed connected to Ground, and if so what the current capability is of that connection.

If the neutral were made ground.. would the results be the same?

Similiar, see previous comment.

if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Similiar... but then you have the situation of when one fails you have no protection on that line.

Cheers,
Tom

 

[Tom.G]

EDITS in Blue[/color]. (Must remember, not after midnite!)

In the United States.. you have Line to Neutral of 120 volts.. and you use it to power your appliances.. if you have 3 phase there.. is it also 120 volts per phase.. meaning if you connect phase to phase.. then it's also 240 volts?

For single family and most multi-family residential the service 120/240V split phase; that is the transformer secondary on the power pole is 240V center-tapped, with the center tap (CT) conneced to Earth at the transformer and also brought to the building with the two 120V wires, where the CT is called Neutral. This Neutral is also grounded at the circuit breaker box with a large wire connected to a long metal rod driven into the Earth. Large appliances, such as an electric stove, are connected to all three wires, making both 120V and 240V available.

In the US. Is there a 120/240 split phase power system? Is it the same as the Delta with 120 volts per phase in my place (and 240 volts line to line)?

Yes, it is available. It is usually used for larger buildings as a way to balance the load across the 3 phases that the power company supplies. At the point of use it is treated as 3 separate supplies, sometimes with a separate electric meter for each.

There is also 120/277V 120/208V 3 phase available for larger multi-family residential and medium industrial. These transformers have 120V secondaries connected in the Wye (or Star) configuration, making a 4 wire supply. The common point (Neutral) of the three secondaries is connected to Earth, brought to the building, and Earthed at the breaker box. 120V is available from any phase to Neutral, and 277V 208V is across any two phases. The 120V is used for the usual wall outlets, etc. The lighting is often 277V single phase fluorescent fixtures, and the 277V 208V 3 phase is for large motors, etc.

Larger industrial typically is supplied with 480V 3 phase, but I don't now the details of that configuration. either Delta or Wye connected. The Wye connected supplies 277V phase to Neutral and 480V across phases. The lighting is often 277V single phase fluorescent fixtures. There would be an on-site transformer to supply 120/240V split phase for wall outlets, etc. (Must have a coffee maker, you understand!)

Thanks for the Prosurge offer, but I have a 120/277V 120/208V service here so it wouldn't be a good fit. Keep it around you may have a use for it, (maybe even next month. who knows!)

Cheers,
Tom

p.s. What is that 24VDC power supply supplying power to?
p.p.s The breaker box photo with the 3 phase breakers must be connected to three split phase transformers somehow.

 

[kiki_danc]

p.s. What is that 24VDC power supply supplying power to?
p.p.s The breaker box photo with the 3 phase breakers must be connected to three split phase transformers somehow.

The 24v dc is connected to a very sophisticated security system with cctc, motion detectors, fire panels, gsm dialers etc

Yes the 3 breakers are connected to each of the 3 phase wire entering the buildings.

So if i buy the siemens 120/240 split phase spd with discrete line to line protection. It should be compatible to my delta 3 phase with 120v each phase?

Reference your post #73.
View attachment 231389Remember that the MOV's act like a resistor when they conduct, their voltages rise as their current increases. The 300V sum of the 2 MOV voltages is close to the 320V of the line-to-line MOV. With the voltages being so close they are sharing the current.The current DIFFERENCE between the 2 elements would typically be shunted to Neutral (which is usually Ground). For instance if one of the MOV's conducted 100A and the other 120A, then 20A would typically flow thru the Neutral lead. There is not enough detail of the test setup nor is it known to me if your Neutral/Common is indeed connected to Ground, and if so what the current capability is of that connection.

In normal power system like in US single phase supply.. when the SPD short circuits to ground.. I thought all the current would go to ground.. isn't it this is the purpose of SPD being connected to ground... where all current would go. In the above experiment, let's say the neutral is connected to ground and have enough wire size.. isn't it the 100A conducted in one would go to the ground? Why did you say only 20A goes to the ground? Also the 2 phase is 120 degree out of phase like in the following:

so when one is conducting.. the other may not.. or you mean they conduct at same time? But why the 20A difference?

Similiar, see previous comment.Similiar... but then you have the situation of when one fails you have no protection on that line.

Cheers,
Tom

The experiment seems to be saying that discrete line to line SPD protection is more effective.. why do you say it's the same? The paper comments on the paragraph about it that:

"In contrast, if an SPD with only seven modes of protection is utilized for the same system and the line-to-line protection mode is proteced by the series combination of the line-to-neutral and neutral-to-line modes or the line-to-ground and ground-to-line modes, then those modes (line-to-neutral or line-to-ground) are intentionally exposed to unnecessary and undesired transient voltages. In essence, the SPD is sharing the line-to-line transient with the line-to-neutral and line-to-ground modes and creating voltages on those modes that would not be present with the use of a discrete all mode protection SPD."

​

What would happen if the ground to neutral is intentionally exposed to unnecessary and undesired transient voltages?

For general line to line protection.. do they use dedicated line to line SPD (without ground but heating the element) or do they use line-to-ground and ground-to-line like in my setup? I want to know if my existing setup is common or not.

 

[Tom.G]

See corrections to my post #78 https://www.physicsforums.com/threads/surge-protector-specs.955697/page-4#post-6064607

(Amazing the things you think of while falling asleep.)

 

[kiki_danc]

Tom. Thanks to you the supplier and distributor have decided to send me a 150Vac SPD for free (after they realized we are right the clamping voltage can increase).. but then I'm having second thought.. I plan to get the Siemens 120/240V split phase at amazon with protection mode that includes L-L. As detailed in my last message, Protection mode that include L-L is more superior than the series connections of two spds, right?

And before I order. I'm verifying if my transformers are really Delta or Wye. Looking at file photos. I found out there was a neutral or ground entering the busbar (white wire among the 3 big black).

This is my actual transformers (some details faded for security).

The two transformers tap to only 2 high tension wires above it, the 3 phase wire entering my service entrance is from the A, B and C terminals. The right transformers has label "x1", "x2", and "x3". So it comes from "x1" and "x3" while on the other side, the terminal C is from "x1".

Do you recognize the transformers as Wye or Delta?

And if I order the Siemens 120/240v split phase at amazon.. it should be compatible by only tapping to the 2 phase of the 3 right? (since I'd just use the admin breaker for the surge protectors and not the full 3 phase breakers).

https://www.amazon.com/Siemens-TPS3A03050-Protective-Lightning-Replacement/dp/B0052NKYC4/ref=sr_1_1?ie=UTF8&qid=1538355017&sr=8-1&keywords=siemens+120/240v+split+phase

Hope to order it soon and done with all this so we can focus back on string theory... lol.. my electrician will install the Siemens don't worry. Thank you.

 

[Tom.G]

Protection mode that include L-L is more superior than the series connections of two spds, right?

Right.

The two transformers tap to only 2 high tension wires above it

With only 2 high tension wires and 2 transformers I fail to see how there can be 3 phases. At a minimum you need a wire and transformer for each phase. Can you supply a sketch of the the wiring for both the primary and secondary of the transformers? For instance there has to be at least 2 terminals wired for both the primary and secondary of each transformer.

I found out there was a neutral or ground entering the busbar (white wire among the 3 big black).

Yes, it looks like the busbar box in the photo already has 120V going thru it. That's the Blk, Wht, Grn trio in the lower right. Wht = Neutral, Blk = Hot, Grn = Earth Ground. Why are you resisting using the existing 120V for the 24VDC power supply? Or even a control transformer to step the 240V down to 120V? After all, the time spent so far already exceeds the cost of a control transformer by a big margin.

 

[kiki_danc]

Right.

With only 2 high tension wires and 2 transformers I fail to see how there can be 3 phases. At a minimum you need a wire and transformer for each phase. Can you supply a sketch of the the wiring for both the primary and secondary of the transformers? For instance there has to be at least 2 terminals wired for both the primary and secondary of each transformer.

Yes, it looks like the busbar box in the photo already has 120V going thru it. That's the Blk, Wht, Grn trio in the lower right. Wht = Neutral, Blk = Hot, Grn = Earth Ground. Why are you resisting using the existing 120V for the 24VDC power supply? Or even a control transformer to step the 240V down to 120V? After all, the time spent so far already exceeds the cost of a control transformer by a big margin.

No. The Green black, white wires in the lower right are connected to another breakers below. I bought green wires 5 years ago because there was no other colors on stock. During installation, the electrician said green is for Earth ground but I already bought 30 meters and it's already cut. So they are not separate power from outside.. but just half meter wires to be connected to a meter below it and breaker and to another room.

Well. In my place all most use line to line of 240 volts. It's rare to use 120 volts. So our neutral or ground is virgin. If I connect the line to ground (of course after asking permission from city hall). And in other floors my hands touch the ground, won't I be jolted by electricity?

My solution is to add a type 3 to the equipments so the 1200 volts or so VPR in the type 1 or 2 would be lowered to 220 volts. This is better solution because remember I have 6 meters wire connecting from type 1 or 2 to equipments.. those can increase the voltage beyond 300 volts..

I'll find the explanation of how they can make 3 phase from 2 wires from high tension wires and 2 transformers and post it later.

 

[kiki_danc]

No. The Green black, white wires in the lower right are connected to another breakers below. I bought green wires 5 years ago because there was no other colors on stock. During installation, the electrician said green is for Earth ground but I already bought 30 meters and it's already cut. So they are not separate power from outside.. but just half meter wires to be connected to a meter below it and breaker and to another room.

Well. In my place all most use line to line of 240 volts. It's rare to use 120 volts. So our neutral or ground is virgin. If I connect the line to ground (of course after asking permission from city hall). And in other floors my hands touch the ground, won't I be jolted by electricity?

My solution is to add a type 3 to the equipments so the 1200 volts or so VPR in the type 1 or 2 would be lowered to 220 volts. This is better solution because remember I have 6 meters wire connecting from type 1 or 2 to equipments.. those can increase the voltage beyond 300 volts..

I'll find the explanation of how they can make 3 phase from 2 wires from high tension wires and 2 transformers and post it later.

I'm sure it's 3 phase from 2 transformers. I used binocular to look at the wires. The wires are tangled so I can't tell the details. But the following is one explanation of how to get 3 phase from 2 transformers.

http://forums.mikeholt.com/showthread.php?t=144067 (better source.. )

https://www.diy-forums.com/threads/three-phase-from-2-transformers.279495/

 

[kiki_danc]

I'm sure it's 3 phase from 2 transformers. I used binocular to look at the wires. The wires are tangled so I can't tell the details. But the following is one explanation of how to get 3 phase from 2 transformers. https://www.diy-forums.com/threads/three-phase-from-2-transformers.279495/

If you will google "3 phase from 2 transformers".. many explanations would come out.. for example:

http://forums.mikeholt.com/showthread.php?t=144067

best explanation in the following from above.. "It's called "open delta". If you Google this term, you will get all kinds of info.

"Picture three transformers providing 240/120V 3� 4W service that you mention. Now remove one not center-tapped. The voltage and phase across the terminals where the removed transformer was formerly connected is still the same.

BTW, POCO's still do this. "

here it says "open delta".. so I guess it answered what kind of transformers I have.. an open delta.. btw.. are you an electrical engineer?

 

[Tom.G]

Yes, I looked at the link you first posted and the links in it. They are all talking about using 2 transformers fed from a 3 phase generator and 3 phase distribution system. That's 3 phases with a 120° phase shift between them on three wires. You stated there are 2 wires in the high tension distribution side, not 3. Even the wikipedia diagram about half way down the page shows a 3 phase supply. How can you receive three different phases on 2 wires? There is only on way to connect a meter or transformer to them

 

[kiki_danc]

Yes, I looked at the link you first posted and the links in it. They are all talking about using 2 transformers fed from a 3 phase generator and 3 phase distribution system. That's 3 phases with a 120° phase shift between them on three wires. You stated there are 2 wires in the high tension distribution side, not 3. Even the wikipedia diagram about half way down the page shows a 3 phase supply. How can you receive three different phases on 2 wires? There is only on way to connect a meter or transformer to them

There are 3 high tension wires above it.. but there is only one terminal per transformer.. I can't see where the third one taps to... where should it be theoretically? Maybe you can find the third wire?

 

[kiki_danc]

There are 3 high tension wires above it.. but there is only one terminal per transformer.. I can't see where the third one taps to... where should it be theoretically? Maybe you can find the third wire?

View attachment 231459

I think I found the third wire.. it's tapped to small terminal (shown in red lines) at left transformer (connecting to the front most high tension wire)… the 2nd is hidden.. the rear high tension wire is connected to the terminal at right transformer

Whatever. It's an Open Delta Transformer.. so the Siemens 120/240V split phase is compatible by connecting to the 2 phases of 3? If yes. I'll order at amazon now and be done with all of this :)

 

[kiki_danc]

I think I found the third wire.. it's tapped to small terminal (shown in red lines) at left transformer (connecting to the front most high tension wire)… the 2nd is hidden.. the rear high tension wire is connected to the terminal at right transformer

View attachment 231460

Whatever. It's an Open Delta Transformer.. so the Siemens 120/240V split phase is compatible by connecting to the 2 phases of 3? If yes. I'll order at amazon now and be done with all of this :)

reviewing my electrical plans.. my wires in admin breaker is 8mm^2 and ground is just 3.5mm^2 to main circuit breaker... so I can't use line to ground because the ground wire size is made smaller because we always use line to line in my place. Anyway in the US.. when you connect line to neutral and get 120 volts.. and you touch the neutral wires in other places in the building or room. won't you get electrocuted? So I'm thinking if I really connect line to ground.. and touch other ground wires.. I may get electrical shock? no?

Whatever, the siemens 120/240V split phase is good to go.. isn't it.. when it's written protection mode includes L-L.. I assume it uses discrete MOV that heats up instead of moving the current to ground.. (?)

 

[Tom.G]

Yes, the Red looks to be the long-lost third wire. And the diagram in post #85 is similar to what I suspected when you said only 2 wires, I just wasn't familiar with the Open Delta configuration. (I learned something new. GREAT!)

But I still don't comprehend why you won't supply 120V thru a transformer to the 24VDC supply. The 240V SPDs won't keep the spikes below the 300V input rating of the supply. That was a limitation you stated earlier in the thread. Can you explain?

Cheers,
Tom

 

[kiki_danc]

Yes, the Red looks to be the long-lost third wire. And the diagram in post #85 is similar to what I suspected when you said only 2 wires, I just wasn't familiar with the Open Delta configuration. (I learned something new. GREAT!)

But I still don't comprehend why you won't supply 120V thru a transformer to the 24VDC supply. The 240V SPDs won't keep the spikes below the 300V input rating of the supply. That was a limitation you stated earlier in the thread. Can you explain?

Cheers,
Tom

I just talked to the power company electrical engineering team. They explained to me that it's government compliance.. back in the 1990s they received order from government never to use line to ground.. this is promote local manufacturers who produced 220 volts appliance.. because if we can use 120 volts.. we could order stuff from the US and our country would lose revenue..so they never allow any applications to be tapping from line to ground.. only line to line.. and if city hall inspect and saw our connection has line to ground.. we may be cited for violation. I guess this answered your question. But then you haven't answered.. if the US 120 volts line connect to ground.. and you touch the ground.. why don't you get electrocuted?

I also asked about the transformer. They confirmed it's Open Delta for 2 transformers of 75 Kva and below. When the usage increases above 150 Kva, then they change to 3 piece WYE transformers..

But if I'll have 220Vac SPD type 3 near equipment cascaded to the 220Vac SPD type 2 at breaker with 220 volts supply.. won't the voltage be below 300 volts? Well.. even if the residual VPR at type 2 is say 3000 volts.. won't it decrease down to 220 volts at the type 3 end?

 

[Tom.G]

That's an interesting explanation of 'No 120V'. It even sort of makes sense. What country are you in?

But then you haven't answered.. if the US 120 volts line connect to ground.. and you touch the ground.. why don't you get electrocuted?

Because the Neutral at the transformer is grounded, AND that Neutral is brought to the breaker box where it is also grounded, AND the Green Earth 'Ground' wire is also connect to Neutral at the breaker box. If the 120V shorts to Ground it is the same as shorting to Neutral, the short essentially short-circuits the transformer and the circuit breaker trips.

For supplying the 24VDC supply, if you use a transformer connected to 240V you are meeting the non-120V requirement and getting the opportunity of better protection for the 24VDC supply. If you have an electric doorbell, it likely runs on about 16VAC from a transformer, which makes it comply with the 240V requirement.

Cheers,
Tom

 

[Tom.G]

That's an interesting explanation of 'No 120V'. It even sort of makes sense. What country are you in?

But then you haven't answered.. if the US 120 volts line connect to ground.. and you touch the ground.. why don't you get electrocuted?

Because the Neutral at the transformer is grounded, AND that Neutral is brought to the breaker box where it is also grounded, AND the Green Earth 'Ground' wire is also connect to Neutral at the breaker box. If the 120V shorts to Ground it is the same as shorting to Neutral, the short essentially short-circuits the transformer and the circuit breaker trips.

For supplying the 24VDC supply, if you use a transformer connected to 240V you are meeting the non-120V requirement and getting the opportunity of better protection for the 24VDC supply. If you have an electric doorbell, it likely runs on about 16VAC from a transformer, which makes it comply with the 240V requirement.

Cheers,
Tom

 

[kiki_danc]

That's an interesting explanation of 'No 120V'. It even sort of makes sense. What country are you in?Because the Neutral at the transformer is grounded, AND that Neutral is brought to the breaker box where it is also grounded, AND the Green Earth 'Ground' wire is also connect to Neutral at the breaker box. If the 120V shorts to Ground it is the same as shorting to Neutral, the short essentially short-circuits the transformer and the circuit breaker trips.

For supplying the 24VDC supply, if you use a transformer connected to 240V you are meeting the non-120V requirement and getting the opportunity of better protection for the 24VDC supply. If you have an electric doorbell, it likely runs on about 16VAC from a transformer, which makes it comply with the 240V requirement.

Cheers,
Tom

You mean using the 150Vac SPD at the secondary end of a 220V primary & 120 volt secondary transformer? I haven't thought of that. But I guess the transformer may not fit inside the circuit panel. And you will have long lead wires enough to bring VPR up high back to 220 volt reference level. If you will put the transformer near the equipment.. you mean using 320 Vac SPD at breakers and 150 Vac SPD at equipment?

 

[Tom.G]

Yes, that's what I was trying to say in post #62 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-4#post-6064111).
320V SPD at transformer primary and 150V SPD at the equipment. Doesn't matter where the transformer is physically placed.

And you haven't answered... What country are you in?

 

[kiki_danc]

Yes, that's what I was trying to say in post #62 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-4#post-6064111).
320V SPD at transformer primary and 150V SPD at the equipment. Doesn't matter where the transformer is physically placed.

And you haven't answered... What country are you in?

By 320V Spd at transformer primary, you mean two 150Vac SPD in series (for phase a to ground and phase b to ground we discussed earlier) giving total of 300Vac.. or maybe you mean line to line 320V SPD. I'd prefer the latter because the former is artificial. In the US, you have hot wire to neutral so it's natural to put one SPD to ground. But for line to line... creating two SPDs in series with ground at middle is kinda artificial.. isn't it. So I need to buy a line to line SPD at breaker.

For the equipment. Since I'd cascade type 3 SPD to type 3 at breaker, voltage from type 3 would be further suppressed to 220 volts.. so why do I have to use transformers.. problem is.. if the transformer gets defective, the MOV element may end up in flame.. Also if you use transformers.. the 120 volts line to ground would become 60 volts.. and there is no 60 volts SPD.. if you use 150 volts SPD just one piece.. it won't work.. it must be two piece since you are protecting line to line... or the new illustration for the transformer secondary end...

I'd msg you in prv for the country for security reasons.

 

[kiki_danc]

By 320V Spd at transformer primary, you mean two 150Vac SPD in series (for phase a to ground and phase b to ground we discussed earlier) giving total of 300Vac.. or maybe you mean line to line 320V SPD. I'd prefer the latter because the former is artificial. In the US, you have hot wire to neutral so it's natural to put one SPD to ground. But for line to line... creating two SPDs in series with ground at middle is kinda artificial.. isn't it. So I need to buy a line to line SPD at breaker.

For the equipment. Since I'd cascade type 3 SPD to type 3 at breaker, voltage from type 3 would be further suppressed to 220 volts.. so why do I have to use transformers.. problem is.. if the transformer gets defective, the MOV element may end up in flame.. Also if you use transformers.. the 120 volts line to ground would become 60 volts.. and there is no 60 volts SPD.. if you use 150 volts SPD just one piece.. it won't work.. it must be two piece since you are protecting line to line... or the new illustration for the transformer secondary end...

View attachment 231462

I'd msg you in prv for the country for security reasons.

If I'm right above that there is no lower than 150 Vac MCOV SPD (the label at right must be 150 instead of 120) and it can't work. Then the only solution is to buy 2 Siemens 120/240V split phase type 1. However, I'd use it as type 2 and type 3. So I guess this will solve all.

Hope you can state now if you don't have adverse comment so I can proceed and finally leave this thread behind. I'm been occupied for this for a week and away from string theory and I feel guilty. Thanks so much Tom.

 

[Tom.G]

Since I'd put type 3, voltage from type 2 would be further suppressed to 220 volts

No it won't. It will be suppressed to between 420V and 1200V per the datasheet you supplied in post #52 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-3#post-6063218) or between 420V and 2000V per the datasheet you supplied in post #26 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-2#post-6060374)

Ideally, the most protection is to use 3 MOVs at the primary and 3 at the load. This will catch both common mode and line-to-line surges.

Then do the same at the primary using 240Vac MOVs. Of course you can use pre-built SPDs.

By the way, decide what you want to happen when an SPD fails shorted.

• Shut off power to the load when they fail, thereby protecting it from further surges.
• Disconnect the MOVs from the circuit while keeping power to the load, but they no longer protect the load.

When most SPDs fail they fail shorted, and will trip the circuit breaker feeding them to remove power.
The one you showed in post #52 is the second option, it keeps power to the load and blows an internal fuse to disconnect a shorted MOV.

You need a fuse or circuit breaker in the power feed to the SPD for the first option.
But don't try to add an external fuse to get the effect of the second option. The fuse sizing and design is a science in itself. Let the manufacturer do it.

Can we put this project to bed yet?

Cheers,
Tom

 

[kiki_danc]

No it won't. It will be suppressed to between 420V and 1200V per the datasheet you supplied in post #52 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-3#post-6063218) or between 420V and 2000V per the datasheet you supplied in post #26 (https://www.physicsforums.com/threads/surge-protector-specs.955697/page-2#post-6060374)

What? You mean even if the output of type 2 from breaker is 1200 volts VPR.. when this inputs into the type 3, it won't get lowered down? Remember the 1200 volts is the voltage output from type 2.. meaning it's the residual voltage instead of 6000 Volts... so when you have voltage that low already.. a type 3 can suppress it down to 220 volts.. Or to make an easier example.. supposed you stand alone type 2 has only surge of 1300 volts.. won't that stand alone spd suppress it down to 220 volts??

Ideally, the most protection is to use 3 MOVs at the primary and 3 at the load. This will catch both common mode and line-to-line surges.

View attachment 231464

Then do the same at the primary using 240Vac MOVs. Of course you can use pre-built SPDs.

By the way, decide what you want to happen when an SPD fails shorted.

• Shut off power to the load when they fail, thereby protecting it from further surges.
• Disconnect the MOVs from the circuit while keeping power to the load, but they no longer protect the load.

When most SPDs fail they fail shorted, and will trip the circuit breaker feeding them to remove power.
The one you showed in post #52 is the second option, it keeps power to the load and blows an internal fuse to disconnect a shorted MOV.

You need a fuse or circuit breaker in the power feed to the SPD for the first option.
But don't try to add an external fuse to get the effect of the second option. The fuse sizing and design is a science in itself. Let the manufacturer do it.

Can we put this project to bed yet?

Cheers,
Tom

 

[Tom.G]

won't that stand alone spd suppress it down to 220 volts??

What does the datasheet say about the type 3 you are proposing? I've lost track of all of the ones we've discussed.