Understanding Surge Protector Specs for the Computer Age

[kiki_danc]

Since the dawn of the computer age.. I never understand much about surge protector specs. So let me ask it now.

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

https://www.meanwell.com/webapp/product/search.aspx?prod=RS-50

It quotes : "Withstand 300VAC surge input up to 5 second"

For 220 Voltage system.. what is the joules it corresponds and how do you compute for it?

https://www.amazon.com/dp/B00009RA5Z/?tag=pfamazon01-20

Here a surge protector quotes: "Surge energy rating 680 Joules".. what VAC surge it can withstand and up to how long (in seconds)? How do you compute?

 

[kiki_danc]

But what's odd is that I've used over 30 equipments like TV, computers for nearly half a century without surge protectors.. and I don't have any fried circuits.. can anyone explain this.. are surge protectors just gimmick?

 

[Rive]

are surge protectors just gimmick?

You are just lucky. Once I've seen a whole street of people who were not lucky. Next day the local electronics repair shop got clogged with TV-sets, stacked three pieces high.

For 220 Voltage system.. what is the joules it corresponds and how do you compute for it?

When it's mentioned in Volts, it means non-standard voltage input from the utility service. When it's Joule, it means energy contained in short spikes, like a lightning strike.
That Meanwell PSU is an industrial product, so it is important to have some tolerance for rough input voltages.
That APC AVR (please next time use a source from the manufacturer) can smooth out anything between 80-130V (in case of 110V output) for indefinite time if the output load is in the specified range: it can also capture spikes up to 700Joule.
http://www.apc.com/salestools/ASTE-6Z7V37/ASTE-6Z7V37_R1_EN.pdf

 

[kiki_danc]

https://www.amazon.com/gp/product/B00966IFQ0/?tag=pfamazon01-20

Let's take the case of the above 4000 joules surge protector. If you have one tv set.. and there is lightning strike or solar storm hit nearby, can it take the blunt of the 4000 joules? or do you need to have 12 tv sets plugged in so you can take advantage of the 4000 joules protection? Normal surge protector is only 600 joules for 4 outlets.. so I wonder if the 4000 joules is due to more outlets only.

 

[Rive]

resource to study

 

[kiki_danc]

resource to study

This seems to be describing other system or using other methods. I was talking about devices or as described: https://en.wikipedia.org/wiki/Surge_protector

"A transient surge protector attempts to limit the voltage supplied to an electric device by either blocking or shorting current to reduce the voltage below a safe threshold. Blocking is done by using inductors which inhibit a sudden change in current. Shorting is done by spark gaps, discharge tubes, zener-type semiconductors, and MOVs (Metal Oxide Varistors), all of which begin to conduct current once a certain voltage threshold is reached, or by capacitors which inhibit a sudden change in voltage. Some surge protectors use multiple elements."

So the devices you mentioned were not the same as these..

 

[Rive]

So the devices you mentioned were not the same as these..

Yes, they are. Just the inductors/spark gaps/varistors/etc are inside the devices.

 

[kiki_danc]

Yes, they are. Just the inductors/spark gaps/varistors/etc are inside the devices.

Which one.. the amazon surge protector or the resource page you shared? Both has them inside the devices.. so what is the difference between them?

If my place electricity has no ground.. do you know devices are more effective that doesn't need any ground?

 

[kiki_danc]

Which one.. the amazon surge protector or the resource page you shared? Both has them inside the devices.. so what is the difference between them?

If my place electricity has no ground.. do you know devices are more effective that doesn't need any ground?

Oh. The SPDs you mentioned are put beside circuit breakers.. while surge protector strip at amazon was where you plug the appliance.. the latter uses joules rating.. while the former didn't.. I bought 5 pcs of the amazon item. I wonder if I should get SPDs instead. Hm..

 

[kiki_danc]

Oh. The SPDs you mentioned are put beside circuit breakers.. while surge protector strip at amazon was where you plug the appliance.. the latter uses joules rating.. while the former didn't.. I bought 5 pcs of the amazon item. I wonder if I should get SPDs instead. Hm..

I just found out the amazon item has clamping voltage of 500 volts.. I read it's too high. Normal should be below 400 voltt. Glad I was able to cancel it in time (it's being prepared for shipment). I got it after seeing this review:

https://wiki.ezvid.com/best-surge-protectors

I'll wait off a day before buying one.. What do you guys recommend?

For those familiar with them. The SPD doesn't have joules rating.. how do you convert between it (joules and other rating) and the surge protector strips (that is not SPD)?

 

[Rive]

The SPDs you mentioned are put beside circuit breakers.. while surge protector strip at amazon was where you plug the appliance..

Type I and/or Type II goes to the switchboard beside the circuit breakers: what you bought (cancelled) is a Type III. I've linked that paper so you can have a vague idea about the bigger picture. It is indeed more about Type I and Type II (since they are selling those).

 

[kiki_danc]

Type I and/or Type II goes to the switchboard beside the circuit breakers: what you bought (cancelled) is a Type III. I've linked that paper so you can have a vague idea about the bigger picture. It is indeed more about Type I and Type II (since they are selling those).

Problem with Type 1 and Type II is that even if the protection is lost (the varistors fried for example).. you won't know it because power still flow.. this can be disastrous for say successive wave of solar storms hitting the grid. Actually for Type III, this is also most often the case. I need APC Fail Safe feature.. specifically: http://www.apc.com/shop/us/en/products/APC-Performance-SurgeArrest-8-Outlet-120V/P-P8 (just an example)

"Fail Safe Mode
Most other surge suppressors continue to let power through even after their circuits have been damaged, leaving your equipment exposed to future surges. APC's SurgeArrest fail safe, which means that once the circuit of an APC SurgeArrest has been compromised the unit disconnects equipment from the power supply ensuring that no damaging surges reach your equipment."

I will take this as no 1 in my list of features along with high joules value and low clamping voltage and 1 ns fast response time. If you know of type 1 or 2 with Fail Safe feature, please let me know. Thanks.

 

[kiki_danc]

Most surge protector strips at amazon has 110 volts rating.. does it mean the circuit is only designed for 110 volts and I can't use 220 volts which is my voltage? What kind of strips can accept both 110 volts and 220 volts?

 

[Nik_2213]

For many years, I ran my home computers (pre-PC) via a high-end, audio-grade spike arrester module. It had a ferrite toroid the size of a hockey puck, stood off lots of domestic switching and network tap-change spikes and transients...

Now, I have a bunch of MOS-based spike catchers plugged in around the house, consider them 'consumables' and keep several spares...
IMHO, 'just one' will not suffice as MOS devices suffer both progressive and sudden attrition.

If your devices have a 'guarded' neon, please check regularly that they haven't quietly 'died in the line of duty'...

 

[kiki_danc]

Something that I'm very concerned with is regarding the fire hazard of surge protectors especially when this would be put in unattended location. See:

http://davesieg.com/your-surge-protector-can-burn-your-house-down/

"Your Surge Protector Can Burn Your House Down!

A business associate recently shared with me some shocking information about surge protectors. If you are like me, you probably have your computer and monitor plugged into an outlet strip that has a surge protector, right? They’re supposed to protect your computer in case there’s a lightning strike or a power surge, right? Well, maybe.

It turns out that the MOV’s (Metal-Oxide Varistors) that are used in Surge protectors offer a short to higher voltages but the usual 120 volts pass right on through to your equipment. Thats good right? Yes, its good if the transient “surge” is short – like 5 or 6 cycles (1/10 second). But if for whatever reason your voltage increases to say 208 volts for even just a few seconds, which can happen if the neutral line of your power feeding your house is compromised, or if there’s a problem with the power feeding your neighborhood, the MOV will quickly burst into flames! Its made even worse because most surge protector strips are plastic and the manufacturers glue the MOVs into the strip with hot-melt glue! (fuel source!)"I was supposed to use surge suppressor on the Honeywell Addressible Fire Control Panel with 20 smoke detectors. The control panel alone costs more than $1000. So here is the dilemma. Use surge protector that can cause fire (where it's supposed to be used on a fire detector) or just take chance and wait for lightning or solar storms to hit the panel. What is your option? Do you know of any surge protector strip that is fire proof? How about the SPD Type 1 and Type 2. Ae they also composed of MOV's that can cause fires?

 

[Vanadium 50]

"Your Surge Protector Can Burn Your House Down!

Hogwash and clickbait.

Yes, they are right - if the power company disconnects the 120V and connects it up to 240V, all your electronics, not just your surge protector can spark. And if an arsonist throws a Molotov cocktail in your window, that can burn your house down too.

 

[Nik_2213]

"Hogwash and clickbait."
Agreed.
Have multiple MOS devices around your house to mitigate the mayhem.
Also, if so concerned, you may need an industrial-strength arrestor upstream of your fuse-box, with a spark-gapped grounding port such as Hams etc use. This will require professional installation, testing and maintenance as, technically, it is a lightning protection system...

 

[russ_watters]

Hogwash and clickbait.

Yes, they are right - if the power company disconnects the 120V and connects it up to 240V, all your electronics, not just your surge protector can spark. And if an arsonist throws a Molotov cocktail in your window, that can burn your house down too.

...and if the gas company suddenly increases your supply pressure by a factor of 10...

 

[kiki_danc]

A Mil-spec surge protector strip made of metal may be more fire resistant than one made of plastic.. but then maybe there is danger of electrified enclosure? For the SPD type 1 and type 2. They are all metal.

I'm still trying to learn how to convert the specs in the SPDs to joules in the strip. No one know any formula?

Best SPDs would be ones where electricity would no longer flow if the surge elements are already damaged. Most in market can still make it flow.

What surge protectors are being used in the LHC or the Israeli Particle Beam Weapon Research Facility? They should be using the best surge protectors in the planet.

 

[Vanadium 50]

What surge protectors are being used in the LHC or the Israeli Particle Beam Weapon Research Facility?

Are you serious? Or just messing with us? Do you seriously believe that the LHC is plugged into a 120 V (OK, 220V, since it's Europe) power strip?

 

[kiki_danc]

I wonder if the LHC PCs and Macs still use surge strips.. although the main lines of course use SPD Type 1 and 2.
If anyone has any information about the surge protection technology used in LHC, please let me know.

Well I have spend several hours reading about surge protectors.. and have finally understood it. Now I'll share what I learnt.

First about Joules as specs... I read https://www.nemasurge.org/faqs/

"Is the Joule rating of an SPD important?
While conceptually a surge protective device (SPD) with a larger energy rating will be better, comparing SPD energy (Joule) ratings can be misleading. More reputable manufactures no longer provide energy ratings. The energy rating is the sum of surge current, surge duration, and SPD clamping voltage.

In comparing two products, the lower rated device would be better if this was as a result of a lower clamping voltage, while the large energy device would be preferable if this was as a result of a larger surge current being used. There is no clear standard for SPD energy measurement, and manufacturers have been known to use long tail pulses to provide larger results misleading the end users.

Because Joule ratings can easily be manipulated many of the industry standards (UL) and guidelines (IEEE) do not recommend the comparison of joules. Instead they put the focus on actual performance of the SPDs with test such as the Nominal Discharge Current testing, which tests the SPDs durability along with the VPR testing that reflects the let-through voltage. With this type of information a better comparison from one SPD to another can be made."

The following are excellent resources that I spent many hours reading and mastering:

https://www.stevejenkins.com/blog/2014/10/whats-the-best-whole-house-surge-protection/
https://www.mikeholt.com/mojonewsar...Protection-Questions-and-Answers~20040708.php

As summary. Power Strips surge protectors which are rated in Joules don't have full data of more important specs.. these power strips are called Type 3. Type 1 is used between the power lines and service entrance and difficult to install because you need to coordinate with the power companies and some don't install these. The LHC definitely has Type 1 SPDs (maybe specially made?). Type II is the most important because they have better specs than most type 3 and you can install this in any breaker panel. What I learned in the above sites is you need to use both Type II and III for optimum protection.

I'll quote the above for these important specifications in choosing real Surge Protector Device (whose data or specs you can't find in the Type 3 power strip surge protectors that is based only on joules).

"Comparing Type 2 Whole-House Surge Protectors
Because I won’t be installing a Type 1 SPD, I wanted to choose a high quality Type 2 whole-house surge protector to act as my first line of defense. During my comparison, I focused my analysis on ten important criteria that should always be considered when evaluating a whole-house surge protection device:

Most importantly: is the unit UL Certified under the UL 1449 3rd Edition and listed as a Transient Voltage Surge Suppressor (TVSS) on the equipment label?

1. What Modes of Protection does the surge protector provide? Ideally, a good whole-house suppressor should protect, at the very least, Line to Neutral (L-N), Neutral to Ground (N-G), and Line to Ground (L-G) on both incoming lines.
2. What is the Maximum Surge Current Capacity of the surge protector? This number should be measured in kA (thousands of amps) per phase, and essentially represents how big a jolt the unit can survive. It’s an important rating, but it’s not the only number to consider when evaluating a surge protector’s true capabilities (more on this later).
3. What is the unit’s Short Circuit Current Rating (SCCR)? This represents the maximum level of short-circuit current that surge protector can withstand.
4. What is the Voltage Protective Rating (VPR) for each Mode of Protection? This is sometimes also referred to as clamping voltage. VPR is like a golf score — lower is actually better. The VPR represents how much voltage is still “let through” to your equipment after the surge protector has done its job. When comparing surge protectors head to head, this rating should be compared based on the same Modes of Protection, and taking the Max Surge Current Capacity into consideration.
5. What is the Maximum Continuous Operating Voltage (MCOV)? MCOV is probably the most important factor to consider when evaluating a surge protector. Higher is better, and it should never be lower than 115% of the system’s nominal voltage for both L-N and L-L. For example, if evaluating a 120V/240V unit and following the 115% rule, the L-N MCOV should be at least 138V and the L-L MCOV should be at least 276V. If it’s not, the surge protector isn’t any good.
6. What is the surge protector’s https://www.nema.org/Products/Documents/nema-enclosure-types.pdf?
7. What type of warranty is offered?
8. What additional connections (phone, coax) are supported? Even if all your power cords are surge protected, surges can still travel through the coax cable that delivers your cable TV/Internet and satellite signal, or phone lines. A comprehensive power protection strategy should also include protection for these connections, too.
9. Does the unit’s price represent a good value? If one unit is more expensive than another unit, is the increased price justified based on the increased features and/or performance?"

Right now I'm looking for a type 2 SPD with lowest Let thru voltage (so called Voltage Protection Rating or clamping voltage) but most seem higher than the Type 3 power strips. This is so because the more capacity is the surge element, the higher the clamping voltage. This is why combining type 2 and 3 may be the best of both worlds as you need cascaded protection and they are called type I, II and III because they are to be used cascaded.

Now back to LHC. What kind of surge protectors do they use? Are they specially made and designed? I haven't seen a power strip surge protection that has type 2 like specs besides joules. Maybe someone can take a look at what kind of surge protectors the LHC computers (PCs and Macs) are connected to? I also plan to visit LHC next year. Can I see the computers and surge protectors they are using?

 

[russ_watters]

I wonder if the LHC PCs and Macs still use surge strips.. although the main lines of course use SPD Type 1 and 2.
If anyone has any information about the surge protection technology used in LHC, please let me know.

Nothing specific to the LHC, but local surge protection is rare in non-residential applications except as a byproduct of plug multiplying (a power strip). For anything worth saving, surge protection is just a small part of larger protection systems, E.G. uninterruptible power supplies.

 

[kiki_danc]

Nothing specific to the LHC, but local surge protection is rare in non-residential applications except as a byproduct of plug multiplying (a power strip). For anything worth saving, surge protection is just a small part of larger protection systems, E.G. uninterruptible power supplies.

But SPD type II has Voltage Rating Protection (clamping voltage) of 1000 Volts for 220 volts AC. It is too high for any 220 volts PSU, that is why power strips with low clamping voltage of about 500 Volt is still required.

I'm looking at the Prosurge with Arc Technology.. it can prevent burnout in event of power surge. But VPR is high at 1000 volts.

http://www.prosurge.com/maximum-safety-in-surge-protection/

 

[kiki_danc]

Most high quality SPD type 2 have high Voltage Protection Rating (clamping voltage). For comparison, say your 120 volts Apple Mac is encountering 600 volts from the surge protection, won't it get damaged? Won't the AC to DC converter in the PSU increase the DC voltage as well?

Clamping voltage is the voltage where the MOV would start to conduct so if it's 600 volts.. that means your Apple Mac can encounter it without the surge protector kicking into action.. what is your comment about his?

 

[russ_watters]

Most high quality SPD type 2 have high Voltage Protection Rating (clamping voltage). For comparison, say your 120 volts Apple Mac is encountering 600 volts from the surge protection, won't it get damaged? Won't the AC to DC converter in the PSU increase the DC voltage as well?

Clamping voltage is the voltage where the MOV would start to conduct so if it's 600 volts.. that means your Apple Mac can encounter it without the surge protector kicking into action.. what is your comment about his?

For this and your previous post, what you are missing is the issue of time. Damage is caused by [over]heating and heating takes time. So the 5 sec at 300V you cited in the OP is just one point on a performance envelope curve. 5 sec is far longer than it takes for a surge protector to trip, so the voltage the PSU can take from it is far higher than 300V. How much? They didnt say, but it is highly likely the problem you think you found does not exist and you are wasting your time trying to solve it.

 

[kiki_danc]

For this and your previous post, what you are missing is the issue of time. Damage is caused by [over]heating and heating takes time. So the 5 sec at 300V you cited in the OP is just one point on a performance envelope curve. 5 sec is far longer than it takes for a surge protector to trip, so the voltage the PSU can take from it is far higher than 300V. How much? They didnt say, but it is highly likely the problem you think you found does not exist and you are wasting your time trying to solve it.

I finally ordered the Prosurge SP320-S SPD with the following specs:

Most SPDs with 220 Volts AC and MCOV of at least 320 Volts has VPR of about 1200 volts.
MCOV needs to be higher than 220 Volts for head-room to avoid heating the elements, etc.

VPR – Voltage Protection Rating. A rating per the latest revision of ANSI/UL 1449, signifying the “rounded up” average measured limiting voltage of an SPD when the SPD is subjected to the surge produced by a 6000 V, 3000 A 8/20 µs combination waveform generator.
In other words, The VPR represents how much voltage is still “let through” to your equipment after the surge protector has done its job.
In the case of the SP320-S. The let-through voltage is 1200 Volts.

The 8/20 µs waveform

Won't the computer or gadget be damaged when you have 1200 Volts at 8/20 µs passing through it? But note a lightning or power plant surge also occurs very fast at 8/20 µs, why would it damage it that the 1200 volts at 8/20 µs won't?

 

[Rive]

Won't the computer or gadget be damaged when you have 1200 Volts at 8/20 µs passing through it?

Of course, it will. If you remember that paper I linked before, protection usually built on a Type2 SPD, with optionally a Type1 as 'muscle' and Type3 for the fine job. The only variation of devices which are not there is exactly when there is just one Type1 is installed.
You just nailed the reason for it.

 

[kiki_danc]

Of course, it will. If you remember that paper I linked before, protection usually built on a Type2 SPD, with optionally a Type1 as 'muscle' and Type3 for the fine job. The only variation of devices which are not there is exactly when there is just one Type1 is installed.
You just nailed the reason for it.

Gee. I have to still look for a type 3? But the problem with type 3 or the long white surge power strips is they are rated at Joules and not UL tested.. there is no specs Imax (maximum discharge current) which is the standard one uses with SPDs. So when a given strip surge has clamping voltage rating.. it's not even tested to be so.. the manufacturer just gives it and you need to believe by faith.

 

[Rive]

Gee. I have to still look for a type 3?

Check that paper again. Systems are just fine with Type 1 & Type 2 already: Type 3 is just an additional (cheap!) last line of defense.
With other words: if to be used together with a well designed Type 1 & Type system you can pick (almost) any Type 3 you want.

 

[kiki_danc]

Check that paper again. Systems are just fine with Type 1 & Type 2 already: Type 3 is just an additional (cheap!) last line of defense.
With other words: if to be used together with a well designed Type 1 & Type system you can pick (almost) any Type 3 you want.

But you just said that the computer or gadget would get damaged if you have 1200 Volts at 8/20 µs passing through it. Most SPD type 2 VPR are in the range of 1200 volts for 220v power system.. so how can you state systems are just fine with type 1 and type 2?

Another thing. Even type 3 SPD still have VPR in the 1000 volts range... see:

http://www.prosurge.com/din-rail-spd-ac-power-supply/

The type 3 has Up of 1300 volts... Up is closely related to VPR... for Up of 1300 volts, VPR is about 1000. Up is the In at nominal discharge current..

 

[kiki_danc]

Is there any electrical engineer here? Can the RS-50-24 in the following be damaged by a 1200 volts passing through it at 8/20 µs? This is the typical voltage protection rating of a SPD type II surge protector after it's done it's job.

https://www.meanwell.com/webapp/product/search.aspx?prod=RS-50

In case our electrical engineers here don't hang out in this C&T forum. I also posted it at the Electrical Engineering forum https://www.physicsforums.com/threads/can-220v-computer-be-damaged-by-1200-volts-8-20-us.955930/

 

[kiki_danc]

The SPD type 2 is finally installed in my house. Note the MCOV is 320Vac. My ac supply is 220Vac.. I can't use 260Vac MCOV because there is none and you need big good allowance because the MOV element can be destroyed if the ac fluctuates to ac rating voltage (and can cause fire).

The green square can become red if the thermal disconnect engaged from 50kA of EMP blast.

Now the problem is the VPR of 1.2kV (1200 volts). The supplier who is a licensed electrical engineer commented the 8/20usecond pulse is only very quick and not enough to heat the computer circuits. When asked for any reference. He can't give any. I think he is just guessing. He doesn't have SPDs below 1200 volts and he can't sell if he would convince his clients the computer can still get fried.

Now I'm looking for a type 3 SPD with say 10kA EMP blast resistance to be added cascaded to the above because here the VPR can be lowered to maybe 500Vac. I can't trust the power strip surge protectors because they are not tested all.. unless perhaps you have used one and can state reason why it can be trusted? What brand of strip surge protectors do you use?

 

[Tom.G]

You need a cable clamp where the wires go thru the wall of the box. At the other end of the wires too. That is a rough, sharp edge around that hole and there is a very real danger of it cutting thru the insulation in the future and causing a short circuit. Whoever did that should be called back and told to make it right. If he refuses, report him to the licensing agency!

DON'T GAMBLE WITH IT, FIX IT!

 

[kiki_danc]

You need a cable clamp where the wires go thru the wall of the box. At the other end of the wires too. That is a rough, sharp edge around that hole and there is a very real danger of it cutting thru the insulation in the future and causing a short circuit. Whoever did that should be called back and told to make it right. If he refuses, report him to the licensing agency!

DON'T GAMBLE WITH IT, FIX IT!

Thanks I'll tell the company right away.

 

[Rive]

Now the problem is the VPR of 1.2kV (1200 volts). ... 8/20usecond pulse...

To put those wires in context I believe this part of the previously linked document will be relevant:

 

[kiki_danc]

The installer returned asap to put the cable clamp (although I think the term is more like tube protector?).

I noticed the wires running from the top to the circuit breaker is about 1 foot. I think the requirement is it should be 6 inches or the VPR would increase? Need to check computation so can let installer make changes to the orientation and wire length.

Anyway. After some pondering... it seems the lower clamping voltage of 500 volts in the white strip surge protectors is equivalent to the higher clamping voltage of the SPDs of 1200 volts. This is because the former uses UL 1339 3rd edition test vector of 6000 volts but only 0.5 kA while the latter test uses UL 1339 4rd edition 6000 volts and 3 kA.. 6 times more... both test still use the 8/20 µs surge pulse.

https://library.e.abb.com/public/1e3ee76b6b93d21ac1257a0f005711d1/Leaflet%20UL1449_Surge%20Protection%20Devices_1TXH%20000%20106%20L0201.pdf quoting:

"The measured voltage protection level. One of the last changes found in the new UL 1449 3rd Edition, is the modification in the measured voltage protection level. The Measured Limiting Voltage (MLV) is the maximum magnitude of voltage measured at the application of a specific impulse wave shape. When applying a certain surge current on the SPD the measured voltage at the device terminals is the so called “let-through voltage.” In UL 1449 2nd Edition, the let-through voltage was referred to as Suppressed Voltage Rating (SVR) and was calculated with a 0.5 kA surge wave form at 6 kV. The new designation is Voltage Protection Rating (VPR) and is calculated with a 3 kA surge wave form at 6 kV.
The MLV will allow comparison of different types of SPDs with regards to the let-through voltage. However, it is important to

Here is another good reference.

https://ewh.ieee.org/r3/nashville/events/2011/Surge Protection Device Standards - IEEE Meeting.pdf

so the 1200 volts is a new standard.. but won't it damage 220 volts equipments.. let's compute... Rive.. more reference welcomed.. thanks..

 

[Tom.G]

To put those wires in context I believe this part of the previously linked document will be relevant:

That fits in nicely with the UL (Underwriters Laboratory) requirement that a type 3 SPD have a minimum of 10 meters of wire betwen it and the type 2 device. That extra 10μH of inductance will really cut the voltage hitting the type 3 SPD.

 

[kiki_danc]

To put those wires in context I believe this part of the previously linked document will be relevant:
View attachment 231139

Got a point. So I scheduled the installer to remove the extra metal box and put the SPD right inside the main panel with only 2 inches of lead wires... do you know the formula why impedance can increase the voltage?

 

[kiki_danc]

That fits in nicely with the UL (Underwriters Laboratory) requirement that a type 3 SPD have a minimum of 10 meters of wire betwen it and the type 2 device. That extra 10μH of inductance will really cut the voltage hitting the type 3 SPD.

Extra wires are supposed to increase the voltage.. not decrease it.. why did you state inductance can decrease voltage? In the voltage-inductance formula.. did it increase or decrease the voltage?

I'd let installer attempt the third. It is supposed to decrease the voltage protection level...

 

[Tom.G]

Extra wires are supposed to increase the voltage.. not decrease it.. why did you state inductance can decrease voltage?

As was stated by @Rive (https://www.physicsforums.com/goto/post?id=6062201#post-6062201), there is a voltage drop across the wires to the SPD. If you have a type 2 SPD at the circuit breakers, 10m of wire, and a type 3 SPD connected directly at the protected device, you get that voltage drop across those 10m wires when the type 3 SPD conducts. This decreases the current and voltage at the protected device, giving you better protection and less stress on the type 3 SPD.

That's how SPDs work, at high voltage they put a short circuit across the wires and count on the impedance of the conductors back to the source to drop the voltage. (or they die trying )

Cheers,
Tom

 

[kiki_danc]

As was stated by @Rive (https://www.physicsforums.com/goto/post?id=6062201#post-6062201), there is a voltage drop across the wires to the SPD. If you have a type 2 SPD at the circuit breakers, 10m of wire, and a type 3 SPD connected directly at the protected device, you get that voltage drop across those 10m wires when the type 3 SPD conducts. This decreases the current and voltage at the protected device, giving you better protection and less stress on the type 3 SPD.

That's how SPDs work, at high voltage they put a short circuit across the wires and count on the impedance of the conductors back to the source to drop the voltage. (or they die trying )

Cheers,
Tom

But this doesn't seem to answer the question why putting the SPD right inside the panel circuit besides the breaker would decrease the VPR or Up.

First some definitions so we are on the same page.

If the leads from the SPD is short.. the Up (voltage protection level) is lower. Why? how do you relate this to impedance and what is the formula(s) involved?

 

[Rive]

I'd let installer attempt the third. It is supposed to decrease the voltage protection level...

Just still keep in mind the local code.
Also, the previously linked document has some wiring/placement suggestions too.

If the leads from the SPD is short.. the Up (voltage protection level) is lower.

The linked picture is about the characteristics of the SPD: that Up is measured on the terminals of the SPD. But since you will use the SPD in an assembly, you have to care about the Up of the assembly (mentioned as 'installed Up'), what will consist of the Up of the SPD and the voltage drop on the wires. About the voltage drop on the wires there was a shortened calculation (with the laws mentioned) on the attachment of post #35

View attachment 231139

 

[kiki_danc]

Just still keep in mind the local code.
Also, the previously linked document has some wiring/placement suggestions too.The linked picture is about the characteristics of the SPD: that Up is measured on the terminals of the SPD. But since you will use the SPD in an assembly, you have to care about the Up of the assembly (mentioned as 'installed Up'), what will consist of the Up of the SPD and the voltage drop on the wires. About the voltage drop on the wires there was a shortened calculation (with the laws mentioned) on the attachment of post #35

View attachment 231139

The attachment is very clear that "As a result, the voltage across the equipment terminals, installed Up, is: installed Up = Up + U1 + U2... " and "... the voltaqe across the equipment terminals will be Up + 500". So longer wires can result in high Up in the installed terminals and UL recommends using very short lead wires. Why do you keep saying the Up will be lower if longer wires or voltage drop??

 

[Dullard]

A geezer trick (from a geezer who designed TVSS equipment in the distant past, FWIW): I sometimes use the 'power strip' type protectors in my house. I always tie as tight a knot as physically possible in the supply cord.

 

[CWatters]

Many countries have standards that equipment must meet. For computers in Europe I think it's EN 50081. Many decades ago I got involved with testing equipment by sending spikes down the mains. It was usually easy to prevent damage ocuring but harder to stop the computer or microprocessor inside crashing or causing data corruption. Fitting filters or suppressors in the power supply isn't always the cure. Sometimes the spikes "couple" into cables or other interconnections.

Edit: that standard has been replaced by EN61000.

 

[kiki_danc]

Let me clarify something:

The above was describing the fact that longer wires cause greater Up or VPR. Yet Tom.G and Rive spoke of voltage drop in a third SPD about 10 meters away from it. Can they or others confirm that they were describing separate fact not being described in the above image? This is important to me because I may do both: Shorten the wires between SPD and breaker and add a second SPD 10 meters away right at equipment (but it's more expensive than the one I bought so need more hard facts). The following graphics showed that shorten lead wires between SPD and breaker can lessen the VPR. And I think this was also being described above (and not about this fact about voltage drop 10 meters away from the SPD which Tom. G and Rive may be confusing the two in the image intended for the VPR increase for longer lead wires between SPD and breaker (?). Another good illustration in the Schneider Electric page.

 

[kiki_danc]

To put those wires in context I believe this part of the previously linked document will be relevant:
View attachment 231139

Rive.. you omitted the left description in the attachment above.. the complete one is:

The left caption quoted: "Connections of a SPD to the loads should be as short as possible in order to reduce the value of the volage protection level (installed Up) on the terminals of the protected equipment."

This seems to be in conflict of your statement that the installed Up would be lower if longer wires (10 meters) are used. Even if you use an SPD type 3 beside the equipment that is 10 meters from the breaker.. won't the effect be like it's 10 meters distance between the SPD and breaker giving rise to huge increases in the Up?

I spent the last 1.5 hours googling all this but can't find the relevant information about this alleged decrease in the voltage with longer length instead of increase so please clarify more clearly. Thank you.

 

[kiki_danc]

As was stated by @Rive (https://www.physicsforums.com/goto/post?id=6062201#post-6062201), there is a voltage drop across the wires to the SPD. If you have a type 2 SPD at the circuit breakers, 10m of wire, and a type 3 SPD connected directly at the protected device, you get that voltage drop across those 10m wires when the type 3 SPD conducts. This decreases the current and voltage at the protected device, giving you better protection and less stress on the type 3 SPD.

That's how SPDs work, at high voltage they put a short circuit across the wires and count on the impedance of the conductors back to the source to drop the voltage. (or they die trying )

Cheers,
Tom

Reviewing about Impedance. It acts like resistance and only valid for high frequency in a straight wire. So you are saying that 10 meters between the equipment and the SPD type 2 install breaker can decrease the residual high frequency surge voltage. But what if you don't add a type 3 a the equipment and just make sure it's 10 meters between them. How much would the 1200 volts VPR output at the Spd type 2 at breaker decrease when it moves through the impedance of the 10 meter length to the equipment (without SPD type 3 present at equipment)?

Presently. The distance between my Type 2 SPD at breaker to equipment is only 5 meters. If I add another 5 meters to make it 10 meters. What would happen to the VPR at the equipment? Would it decrease from 1200 volts to 600 volts (even without type 3 spd installed).

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.

I asked the suppliers of SPDs in my place and they are not familiar with the technical. One of them doesn't even know the meaning of SCCR or In or about impedance mismatched. They just sell you the SPDs and install it (this is why the wiring in my installed SPD is very long because they ignore all this important technical detail). I even asked directly the manufacturer of Prosurge, the region sale head is not very familiar and asked me to ask my local supplier (who doesn't know the details).

 

[Rive]

This seems to be in conflict of your statement that the installed Up would be lower if longer wires (10 meters) are used.

There is no conflict at all. You just repeatedly mistaking the wires used to install the type2 SPD into the switchbox with wires connecting the switchbox to the protected equipment (which hopefully has a type3 SPD).

By the way the letter type of 10m wire was the contribution of @Tom.G in post #37.

Ps.: due 'omitting' and such I don't really feel like putting any more effort here.

 

[kiki_danc]

There is no conflict at all. You just repeatedly mistaking the wires used to install the type2 SPD into the switchbox with wires connecting the switchbox to the protected equipment (which hopefully has a type3 SPD).

By the way the letter type of 10m wire was the contribution of @Tom.G in post #37.

Ps.: due 'omitting' and such I don't really feel like putting any more effort here.

Googling further. I found the following text and image which seems to suggest that longer wires (whether between type 2 spd and switchbox or between switchbox to the protected equipment) can both lead to voltage increase (not decrease in the case of the latter)...

http://engineering.electrical-equip...ution/lv-coordination-2-surge-protectors.html

"If the length of cable between the “main” surge arrester and the equipment to be protected is too long, oscillations and wave reflections may lead to tensions in the equipment; these tensions can be above the Up level of the same surge protector (until doubled up)

Next figure is : Voltage curve at the end of the cable depending on length of cable (front voltage =4kV/µs)"

If one will still state that 10 meters can cause voltage drop from the impedance (Tom G).. please show proof or calculations or reference because I have googled a lot and I just can't find the reference the wires between the switchbox and equipment can cause voltage drop (the above shows there is voltage increase instead). This is important for sake of discussion and facts.