Understanding Surge Protector Specs for the Computer Age

[Tom.G]

They will be working in parallel, sharing the load of the surge; like a game of tug-of-war where you have several people pulling on opposite ends of a rope. The more people pulling together the more effective they are.

The type 3 specification (UL1449) says must be 10 meters of wire. Probably to limit the current thru the SPD. I haven't read the spec for type 2, but since they are intended for use in the breaker box they probably have a higher peak current capability, counting on the larger but longer service entrance wires for voltage drop. I think I gave the link to the UL page in an earlier post, why don't you read it and see what you can find out about type 2?

Cheers,
Tom

 

[kiki_danc]

They will be working in parallel, sharing the load of the surge; like a game of tug-of-war where you have several people pulling on opposite ends of a rope. The more people pulling together the more effective they are.

The type 3 specification (UL1449) says must be 10 meters of wire. Probably to limit the current thru the SPD. I haven't read the spec for type 2, but since they are intended for use in the breaker box they probably have a higher peak current capability, counting on the larger but longer service entrance wires for voltage drop. I think I gave the link to the UL page in an earlier post, why don't you read it and see what you can find out about type 2?

Cheers,
Tom

I have read it over and over. But remember my situation is i'll put a high surge capacity (50kA) Type 2 at the equipment 5 meters away. Since my SPD has high surge current capacity, then it's not sensitive to the current. But I'm concerned about impedance and planning to add 5 meters of wire in loop (see pic below) just to meet the 10 meters. And I'm asking to what extend can the SPD lower the voltage for 10 meters impedance versus just 1 inch wire (between 2 SPDs put side by side at breaker panel where the 2nd farther SPD 1 inch away would only see the 1 inch wire impedance and not see the longer service entrance wire). May I know the formula to relate voltage and impedance and why longer wires can bring the voltage down? Thank you.

https://standardscatalog.ul.com/standards/en/standard_1449

1 Scope
1.1 These requirements cover enclosed and open-type Surge Protective Devices (SPDs) designed for repeated limiting of transient voltage surges as specified in the standard on 50 or 60 Hz power circuits not exceeding 1000 V and for PV applications up to 1500 V dc and designated as follows:

Type 1 – One port, permanently connected SPDs, except for watt-hour meter socket enclosures, intended for installation between the secondary of the service transformer and the line side of the service equipment overcurrent device, as well as the load side, including watt-hour meter socket enclosures and Molded Case SPDs intended to be installed without an external overcurrent protective device. Type 1 SPDs for use in PV systems can be connected between the PV array and the main service disconnect.

Type 2 – Permanently connected SPDs intended for installation on the load side of the service equipment overcurrent device; including SPDs located at the branch panel and Molded Case SPDs.

Type 3 – Point of utilization SPDs, installed at a minimum conductor length of 10 meters (30 feet) from the electrical service panel to the point of utilization, for example cord connected, direct plug-in, receptacle type and SPDs installed at the utilization equipment being protected. See marking in 80.3. The distance (10 meters) is exclusive of conductors provided with or used to attach SPDs.

Type 4 Component Assemblies – Component assembly consisting of one or more Type 5 components together with a disconnect (integral or external) or a means of complying with the limited current tests in 44.4.

Type 1, 2, 3 Component Assemblies – Consists of a Type 4 component assembly with internal or external short circuit protection.

Type 5 – Discrete component surge suppressors, such as MOVs that may be mounted on a PWB, connected by its leads or provided within an enclosure with mounting means and wiring terminations.

1.2 Except as indicated in 1.3, the products covered by this Standard are rated and intended for connection to circuits or supply sources having nominal voltage ratings as specified in Table 44.1.

1.3 A product intended for connection to an ac circuit or supply source other than that specified in 1.2 may be examined and tested in accordance with the intent of the requirements in this standard and, if found to be substantially equivalent, may be judged to comply with this Standard.

1.4 These requirements cover cord-connected direct plug-in, and permanently connected SPDs intended for indoor and outdoor use in accordance with the National Electrical Code, ANSI/NFPA-70.

1.5 These requirements do not cover the interconnection of multiple field installed SPDs.

1.6 These requirements cover SPDs that may include components specifically intended to function as filters for conducted electromagnetic interference (EMI) or noise, in addition to limiting transient voltage surges. See Section 26.

1.7 These requirements cover SPDs employing circuit components intended to provide secondary protection for telephone communication circuits and circuit components intended to protect data communication or fire alarm circuits. See Section 27.

1.8 These requirements cover SPDs employing antenna connections for audio-video products. See Section 28.

1.9 An SPD that has a battery backup feature or other uninterruptible power supply equipment shall also comply with the applicable requirements in the Standard for Uninterruptible Power Supply Equipment, UL 1778. See Section 30.

1.10 These requirements cover SPDs/Panelboard Extension Modules. These products shall also comply with the Standard for Panelboards, UL 67. See Section 31.

1.11 These requirements do not evaluate the effect of SPDs on connected loads, the effect of SPDs on harmonic distortion of the supply voltage, the degree of attenuation provided by SPDs, nor the adequacy of the voltage protection rating of SPDs to protect specific connected equipment from upset or damage.

1.12 This standard does not cover cord connected or direct plug-in SPDs intended for use with medical equipment. Medical equipment is typically intended for use in General Patient Care Areas or Critical Patient Care Areas as defined by Article 517 of the National Electrical Code for Health Care Facilities. SPDs intended for such use shall comply with the requirements of the Standard for Safety of Medical Electrical Equipment, Part 1: General Requirements, UL 60601-1, and the Standard for Safety Requirements for Medical Electrical Systems, IEC 60601-1-1.

1.13 An SPD intended to serve as an outlet cover plate or outlet box hood shall comply with the requirement for faceplates in the Standard for Cover Plates for Flush Mounted Wiring Devices,UL 514D.

1.14 An SPD intended for use in a Lightning Protection System (LPS) shall comply with the Surge Protection requirements in the Standard for Installation Requirements for Lightning Protections Systems, UL 96A.

1.15 A Type 3 SPD may employ additional low voltage supplementary circuitry to power a USB charger.

1.16 A cord-connected or direct plug-in Type 3 SPD may employ a replaceable or non-replaceable rechargeable battery to power a USB output circuit.

1.17 A direct plug-in SPD employing more than two receptacles shall also comply with the applicable requirements in the Standard for Current Taps and Adapters, ANSI/UL 498A.

1.18 A cord-connected SPD employing more than two receptacles shall also comply with the applicable requirements in the requirements in the Standard for Relocatable Power Taps, UL 1363 or the Standard for Furniture Power Distribution Units, UL 962A.

 

[kiki_danc]

I have read it over and over. But remember my situation is i'll put a high surge capacity (50kA) Type 2 at the equipment 5 meters away. Since my SPD has high surge current capacity, then it's not sensitive to the current. But I'm concerned about impedance and planning to add 5 meters of wire in loop (see pic below) just to meet the 10 meters. And I'm asking to what extend can the SPD lower the voltage for 10 meters impedance versus just 1 inch wire (between 2 SPDs put side by side at breaker panel where the 2nd farther SPD 1 inch away would only see the 1 inch wire impedance and not see the longer service entrance wire). May I know the formula to relate voltage and impedance and why longer wires can bring the voltage down? Thank you.

View attachment 231595

https://standardscatalog.ul.com/standards/en/standard_1449

To reword my inquiry above in case you didn't get the central concern. For the 2 SPD put side by side with 1 inch distance between them in the main breaker panel. Would the 2nd SPD 1 inch away from the first SPD see the 1 inch wire or the entire service entrance wire for the impedance? If it can see the entire service entrance wire.. how come the SPD 5 meters away can't see the entire service entrance wire for the impedance? I'm preparing to add 5 meters but just wondering of the behavior of the SPD 1 inch away from first SPD and the SPD 5 meters away from first SPD.

 

[kiki_danc]

To reword my inquiry above in case you didn't get the central concern. For the 2 SPD put side by side with 1 inch distance between them in the main breaker panel. Would the 2nd SPD 1 inch away from the first SPD see the 1 inch wire or the entire service entrance wire for the impedance? If it can see the entire service entrance wire.. how come the SPD 5 meters away can't see the entire service entrance wire for the impedance? I'm preparing to add 5 meters but just wondering of the behavior of the SPD 1 inch away from first SPD and the SPD 5 meters away from first SPD.

View attachment 231596

Or if the rewording above is still confusing.. see the following illustration:

Assuming there is long service entrance wire and SPD 1 can see it... can SPD 2 one inch away from SPD 2 also see the long service entrance wire impedance? If yes.. how come the SPD 3 can't see the longer service entrance wire impedance?

 

[kiki_danc]

Here's a last question Tom (I promise last question because if we go on more and it will produce critical information not many know.. I'm afraid ignorant SPD suppliers may print all of these making them as quick manual for newbie technicians and my security would be compromised since I have many pictures (Most technicians and suppliers don't know this level of information.. for example my supplier told me he has never tried connecting it line to line and always line to ground since it's how they are commonly installed). So okay if you don't give detailed impedance computations. I'd ask this in separate message in other forums or website to dilute the information.

The last question concerns neutral and ground. I plan to purchase this Siemens 120/240V Split Phase 140,000 A surge protector to put line to line besides the prosurge 320Vac I already installed at breaker panel... but I saw at amazon this review: https://www.amazon.com/dp/B013WINMK6/?tag=pfamazon01-20

amazon review:
"Falsely reports ground to neutral problem By Mark M Harbaughon August 16, 2018
The SPD falsely reported a neutral to gnd problem when none existed. A replacement SPD functions properly and does not report a neutral to ground problem."

And in the product literature it is mentioned:

"The SPD is equipped with an audible alarm which will sound in the event of an alarm condition. This indicates a problem with the SPD which requires further evaluation. There is no test or silence switch. De-energizing the SPD will silence the alarm."

So I'm afraid the alarm may sound continuously if it detects something wrong with my ground.

Something is wrong in our ground or neutral because in my country compared to US, (to summarize briefly) we used your split phase 120/240V phase to phase power system to power our buildings with government complied 240 volts. We don't use phase to neutral 120 volts nor use neutral to ground bonding at panel. Therefore the neutral in the Open Delta transformer is connected to our breaker panel as ground (no separate ground). In most homes without Open Delta transformations. I have confirmed there is not even ground or neutral wires coming to the house. For the particular Open Delta supplied building like mine. Our ground is neutral wire connected to the transfomers. Now since we don't have separate neutral and ground. I'm afraid the Siemens device will keep sounding alarm (as well as all other brands of 120/240v split phase surge protectors at amazon). Any idea how to make proper neutral and ground so it can be connected to the proper Siemens leads without sounding fault alarm.. this is illustrated thus:

Again my transformer Neutral is used as Ground in our building without separate ground. If our aircon housing is connected to neutral in the transformers. What problem would this produce and what is meant by ground to neutral fault in the US that can cause problem with the Siemens Device.

btw.. does this user review makes any sense: https://shedheads.net/whole-house-surge-protectors
"Sizing a surge protector can be a challenge. The larger capacity models can protect against the largest surges, but let small ones pass. This means that some of your smallest, most delicate electronics can be damaged. Meanwhile, most of the smaller surge protectors aren’t sized to handle massive surges.
This siemens model is the exception. It has a “three stage” protection system that enables it to catch all surges, both large and small.
"

Do you believe it's true that Sizing a surge protector can be a challenge. That larger capacity models can protect against the largest surges, but let small ones pass? I haven't read this in surge literature.. is there a basis for it?

Again thanks very much and this is really my last inquiry for security concerns.

 

[Tom.G]

Would the 2nd SPD 1 inch away from the first SPD see the 1 inch wire or the entire service entrance wire for the impedance?

The second SPD will see the entire service entrance wire for the impedance. (plus a tiny bit from the extra 1 inch)

how come the SPD 5 meters away can't see the entire service entrance wire for the impedance?

It can. The problem arises due to the relatively low service entrance impedance and the lower current capability of the type 3 SPDs.

what is meant by ground to neutral fault in the US that can cause problem with the Siemens Device.

In the U.S., the Ground and Neutral are connected together. Apparently the Siemens SPD checks this connection and complains if they are not connected.

Any idea how to make proper neutral and ground so it can be connected to the proper Siemens leads without sounding fault alarm.

This refers to the SPDs in the breaker box. The type 3 at the equipment, if any, is addressed below.
1) CHECK WITH YOUR POWER COMPANY to see if this is both safe and legal before you do this step. This suggestion is based on the U.S. National Electrical Code (NEC) and may not be appropriate where you are located.
From a safety and effectiveness standpoint, drive an 8 foot ground rod into the Earth near the breaker panel. Then run a wire not smaller than the service entrance conductors from the ground rod to the breaker box. Make the wire run as straight as possible and any needed bends should be gentle (large bend radius), not sharp 'square corners'. The gentle bends present a better path for high current lightning strikes, sharp bends tend to induce any high voltages to jump to other nearby conductors.

• 
  Now you have two options:
  • Connect the new Ground wire to the Neutral in your breaker box AND to the ground wire of the SPD.
  • Connect the new Ground wire only to the ground wire of the SPD.

2) If the above is not possible/practicle, to disable the alarm on the SPD, connect the SPD ground wire to the same place the SPD neutral wire is connected. (not ideal, but better than nothing.)

That larger capacity models can protect against the largest surges, but let small ones pass? I haven't read this in surge literature.. is there a basis for it?

Look at the VPR and the maximum Amperage of type 1 or 2 SPDs versus the type 3 SPDs.

* to summarize: type 1 or 2 SPD at breaker box. Type 3 at the equipment with either a transformer or at least 10 meters of wire from the type 1 or 2. If there is a type 3 at the equipment, connect its ground wire to the new Ground wire from the 8 foot Ground rod referenced above for the breaker box.
Documentation for the FS140 (https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43434) states on page 2 (pg 4 of the .PDF) that the voltage drop of a surge pulse is 175V per foot (574V per meter). That means the 10 meters of wire can drop the surge voltage by 5,740V provided there is a surge suppressor at that 10 meter position.

Cheers,
Tom

 

[kiki_danc]

The second SPD will see the entire service entrance wire for the impedance. (plus a tiny bit from the extra 1 inch)

It can. The problem arises due to the relatively low service entrance impedance and the lower current capability of the type 3 SPDs.

I was asking this yesterday to possibly justify not adding 5 meters of wire to existing 5 meters to comply with UL minimum 10 meters to equipment.. but 2 hours before your reply before we already installed it with electrician:

It's Prosurge 50,000A surge capable Type 2 with 5 meters of wires in loop added to existing 5 meters making up 10 meters from main breaker panel and besides the equipments (the green wire is existing and I know I made wrong color choice years ago, the black wire is the additional 5 meters). This is pictured energized so all is well. Now this question is just to clarify above and academic (since I already installed it). You said type 3 can see the service entrance wires which has low impedance and type 3 supposedly have lower surge current capability. I don't get it. If it has type 3 with low surge current capability.. why can't low impedance be enough for it? Isn't it low current and low impedance go together? Because you seemed to be implying low surge current capability type 3 needs high impedance?

And for my actual implementation (temporary as I'm waiting for 150Vac SPD and 220V-110V transformer implementation hence the no wire clamp is just temporary), I didn't use low surge current capable type 3 but the samehigh 50,000A surge current which I now put both at breaker panel and 10 meters away from it near equipment. So how does this change your statement about "The problem arises due to the relatively low service entrance impedance and the lower current capability of the type 3 SPDs" as it pertains to whether the type 3 can see the service entrance wires. With my high current surge type 3.. what would it see? Should the 10 meters requirement be theoretically increased or decreased if high surge current type 3 is used?

Thanks.

In the U.S., the Ground and Neutral are connected together. Apparently the Siemens SPD checks this connection and complains if they are not connected.This refers to the SPDs in the breaker box. The type 3 at the equipment, if any, is addressed below.
1) CHECK WITH YOUR POWER COMPANY to see if this is both safe and legal before you do this step. This suggestion is based on the U.S. National Electrical Code (NEC) and may not be appropriate where you are located.
From a safety and effectiveness standpoint, drive an 8 foot ground rod into the Earth near the breaker panel. Then run a wire not smaller than the service entrance conductors from the ground rod to the breaker box. Make the wire run as straight as possible and any needed bends should be gentle (large bend radius), not sharp 'square corners'. The gentle bends present a better path for high current lightning strikes, sharp bends tend to induce any high voltages to jump to other nearby conductors.

• 
  Now you have two options:
  • Connect the new Ground wire to the Neutral in your breaker box AND to the ground wire of the SPD.
  • Connect the new Ground wire only to the ground wire of the SPD.

2) If the above is not possible/practicle, to disable the alarm on the SPD, connect the SPD ground wire to the same place the SPD neutral wire is connected. (not ideal, but better than nothing.)Look at the VPR and the maximum Amperage of type 1 or 2 SPDs versus the type 3 SPDs.

* to summarize: type 1 or 2 SPD at breaker box. Type 3 at the equipment with either a transformer or at least 10 meters of wire from the type 1 or 2. If there is a type 3 at the equipment, connect its ground wire to the new Ground wire from the 8 foot Ground rod referenced above for the breaker box.
Documentation for the FS140 (https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43434) states on page 2 (pg 4 of the .PDF) that the voltage drop of a surge pulse is 175V per foot (574V per meter). That means the 10 meters of wire can drop the surge voltage by 5,740V provided there is a surge suppressor at that 10 meter position.

Cheers,
Tom

 

[kiki_danc]

I was asking this yesterday to possibly justify not adding 5 meters of wire to existing 5 meters to comply with UL minimum 10 meters to equipment.. but 2 hours before your reply before we already installed it with electrician:

View attachment 231644

It's Prosurge 50,000A surge capable Type 2 with 5 meters of wires in loop added to existing 5 meters making up 10 meters from main breaker panel and besides the equipments (the green wire is existing and I know I made wrong color choice years ago, the black wire is the additional 5 meters). This is pictured energized so all is well. Now this question is just to clarify above and academic (since I already installed it). You said type 3 can see the service entrance wires which has low impedance and type 3 supposedly have lower surge current capability. I don't get it. If it has type 3 with low surge current capability.. why can't low impedance be enough for it? Isn't it low current and low impedance go together? Because you seemed to be implying low surge current capability type 3 needs high impedance?

And for my actual implementation (temporary as I'm waiting for 150Vac SPD and 220V-110V transformer implementation hence the no wire clamp is just temporary), I didn't use low surge current capable type 3 but the samehigh 50,000A surge current which I now put both at breaker panel and 10 meters away from it near equipment. So how does this change your statement about "The problem arises due to the relatively low service entrance impedance and the lower current capability of the type 3 SPDs" as it pertains to whether the type 3 can see the service entrance wires. With my high current surge type 3.. what would it see? Should the 10 meters requirement be theoretically increased or decreased if high surge current type 3 is used?

Thanks.

Let me reword this last inquiry about impedance as I'm quite confused by it and can't shake the feelings.

1. You said the service entrance has low impedance... this means the SPD 1 & 2 are not so effective in lowering the voltage because it needs high impedance?

2. You need 10 meters to SPD 3 at equipment so the SPD3 there can lower the voltage more effectively.. but can't the type 1 or 2 at breaker entrance sees the 10 meters wire from it to the SPD 3 or does it only see the low impedance at service entrance wire?

3. Does this mean service entrance wire should be long so it would become high impedance for the Spd 1 & 2 to decrease the voltage more effectively...

4. What's so confusing is why is impedance needed to lower voltage. If you have a stand alone SPD with high voltage introduced to it.. the mere fact the MOV conducts means the voltage difference is lowered.. why is impedance important? Wikipedia defines impedance as: Electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied. So I can't quite get why it is need to bring the voltage down. I'm quite dumb in this thing. Appreciate a million for your help Tom!

 

[kiki_danc]

The second SPD will see the entire service entrance wire for the impedance. (plus a tiny bit from the extra 1 inch)

It can. The problem arises due to the relatively low service entrance impedance and the lower current capability of the type 3 SPDs.

Googling has led me to electrical engineering section in stack exchange.. I think the details of the above is because if the wires are not 10 meters.. there is not enough inductance to limit the current. Not only this. But the clamping won't work well without the impedance in the wires. So I guess it has double purpose. I guess this answers my own questions in the message prior to this. I'll grill the electrical engineers there if I have more detail questions about the technical aspects of it.

About the transformer. You may make sense about lowering down 220 volts to 110 volts to get lower clamping voltage. I wonder if all those countries with 220 volts also use 110 step down transformer to get lower clamping voltage? Well. I have difficulty finding plug in SPDs made in USA (I don't want made in china anymore). Most are integrated. So I wonder what would happen if I used transformer and get 110 volts line to line.. Would the dozens of intergrated SPDs made in US able to distinguish between whether the 110 volts came from line to neutral (in the US power system) or came from line to line (in my country)? If not. Then I can get any products there.. if it can distinguish.. then I'm stuck to plug in stand alone SPDs. Your last answer here would help me decide whether to get the dozens of available integrated SPDs like the Siemens or others. As always thanks you so much Tom.

In the U.S., the Ground and Neutral are connected together. Apparently the Siemens SPD checks this connection and complains if they are not connected.This refers to the SPDs in the breaker box. The type 3 at the equipment, if any, is addressed below.
1) CHECK WITH YOUR POWER COMPANY to see if this is both safe and legal before you do this step. This suggestion is based on the U.S. National Electrical Code (NEC) and may not be appropriate where you are located.
From a safety and effectiveness standpoint, drive an 8 foot ground rod into the Earth near the breaker panel. Then run a wire not smaller than the service entrance conductors from the ground rod to the breaker box. Make the wire run as straight as possible and any needed bends should be gentle (large bend radius), not sharp 'square corners'. The gentle bends present a better path for high current lightning strikes, sharp bends tend to induce any high voltages to jump to other nearby conductors.

• 
  Now you have two options:
  • Connect the new Ground wire to the Neutral in your breaker box AND to the ground wire of the SPD.
  • Connect the new Ground wire only to the ground wire of the SPD.

2) If the above is not possible/practicle, to disable the alarm on the SPD, connect the SPD ground wire to the same place the SPD neutral wire is connected. (not ideal, but better than nothing.)Look at the VPR and the maximum Amperage of type 1 or 2 SPDs versus the type 3 SPDs.

* to summarize: type 1 or 2 SPD at breaker box. Type 3 at the equipment with either a transformer or at least 10 meters of wire from the type 1 or 2. If there is a type 3 at the equipment, connect its ground wire to the new Ground wire from the 8 foot Ground rod referenced above for the breaker box.
Documentation for the FS140 (https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43434) states on page 2 (pg 4 of the .PDF) that the voltage drop of a surge pulse is 175V per foot (574V per meter). That means the 10 meters of wire can drop the surge voltage by 5,740V provided there is a surge suppressor at that 10 meter position.

Cheers,
Tom

 

[kiki_danc]

Googling has led me to electrical engineering section in stack exchange.. I think the details of the above is because if the wires are not 10 meters.. there is not enough inductance to limit the current. Not only this. But the clamping won't work well without the impedance in the wires. So I guess it has double purpose. I guess this answers my own questions in the message prior to this. I'll grill the electrical engineers there if I have more detail questions about the technical aspects of it.

About the transformer. You may make sense about lowering down 220 volts to 110 volts to get lower clamping voltage. I wonder if all those countries with 220 volts also use 110 step down transformer to get lower clamping voltage? Well. I have difficulty finding plug in SPDs made in USA (I don't want made in china anymore). Most are integrated. So I wonder what would happen if I used transformer and get 110 volts line to line.. Would the dozens of intergrated SPDs made in US able to distinguish between whether the 110 volts came from line to neutral (in the US power system) or came from line to line (in my country)? If not. Then I can get any products there.. if it can distinguish.. then I'm stuck to plug in stand alone SPDs. Your last answer here would help me decide whether to get the dozens of available integrated SPDs like the Siemens or others. As always thanks you so much Tom.

or to rephrase the above in more US friendly language.. if you Americans use your phase to phase of 240 volts and use 240v to 120 volts transformers.. can your integrated SPD like the Siemens able to connect Phase to Neutral to your 120v line to line transformered ac system? Remember we have same power system only the usage is regulated (we can't use 120v to avoid inflating Trump pockets) so the answer to that applies exactly to my application. In the case of the Siemens, if you short ground to neutral so the alarm won't go off.. I wonder if this can work too in this transformered setup (your "connect the SPD ground wire to the same place the SPD neutral wire is connected" stuff for the normal case). If yes, I'd order two pieces of Siemens.. one to use at breaker entrance to add to existing and the 2nd as type 3 (because I can't find stand-alone US made SPDs like the Prosurge at amazon).

 

[jim mcnamara]

This thread is dragging on a bit. I'll try to help: let's move it to electrical engineering, which is really what 90% of the discussion is about. @jim hardy has discussed this before I think.

 

[Tom.G]

Googling has led me to electrical engineering section in stack exchange.. I think the details of the above is because if the wires are not 10 meters.. there is not enough inductance to limit the current. Not only this. But the clamping won't work well without the impedance in the wires. So I guess it has double purpose. I guess this answers my own questions in the message prior to this. I'll grill the electrical engineers there if I have more detail questions about the technical aspects of it.

Good! It sounds like you learned a bunch there. I started an rudimentary explanation last night... then the Internet went down in the neighborhood! Something about the Internet provider having a power outage. But you probably got a lot more background information on your stack exchange journey.

About the transformer. You may make sense about lowering down 220 volts to 110 volts to get lower clamping voltage. I wonder if all those countries with 220 volts also use 110 step down transformer to get lower clamping voltage? Well. I have difficulty finding plug in SPDs made in USA (I don't want made in china anymore). Most are integrated. So I wonder what would happen if I used transformer and get 110 volts line to line.. Would the dozens of intergrated SPDs made in US able to distinguish between whether the 110 volts came from line to neutral (in the US power system) or came from line to line (in my country)?

If you use a 240/120V transformer and an added physical Ground as in post #126 and repeated below, the US type 3 plug-in SPDs will see exactly what they need and will work fine. It will likely be difficult to find any that are actually made in the US though.

Remember we have same power system only the usage is regulated (we can't use 120v to avoid inflating Trump pockets) so the answer to that applies exactly to my application.

I disagree. If you had the same or even equivalent system, this discussion would have concluded many pages ago.

The difference is:

• The US has a Ground-referenced electrical system with an additional electrical Ground 'Safety Ground' at each outlet.
• Yours is NOT Ground referenced (as indicated by you getting a shock from the Neutral wire) and has NO 'Safety Ground'. (Green wire)

These differences make it difficult/impossible to get both maximum surge protection AND maximum protection to Humans and nearby equipment.

The Siemens FS140 seems a very good choice for a Ground referenced system with a Safety Ground. You can approach that maximum protection for your system by using a 240/120V transformer, adding a physical Ground connection as described in post #126, connecting one transformer secondary lead to the physical Ground connection, and using a Siemens FS140 SPD at the load with its ground wire connected your physical Ground as described in post #126. Anything less is wishful thinking and hoping 'It's good enough'. Nothing is perfect, even with unlimited time and funds, I'm trying to come up with 'best practices' solutions that fit in your constraints.

Now that this thread is in the Elecrical Engineering section maybe others can come up with better solutions.
(But of course by biased opinion is 'it's pretty darn good so far.' )

I think many of us learned a whole bunch of stuff throughout this project. I sure did!

Cheers,
Tom

 

[kiki_danc]

Good! It sounds like you learned a bunch there. I started an rudimentary explanation last night... then the Internet went down in the neighborhood! Something about the Internet provider having a power outage. But you probably got a lot more background information on your stack exchange journey.
If you use a 240/120V transformer and an added physical Ground as in post #126 and repeated below, the US type 3 plug-in SPDs will see exactly what they need and will work fine. It will likely be difficult to find any that are actually made in the US though.I disagree. If you had the same or even equivalent system, this discussion would have concluded many pages ago.

The difference is:

• The US has a Ground-referenced electrical system with an additional electrical Ground 'Safety Ground' at each outlet.
• Yours is NOT Ground referenced (as indicated by you getting a shock from the Neutral wire) and has NO 'Safety Ground'. (Green wire)

These differences make it difficult/impossible to get both maximum surge protection AND maximum protection to Humans and nearby equipment.

The Siemens FS140 seems a very good choice for a Ground referenced system with a Safety Ground. You can approach that maximum protection for your system by using a 240/120V transformer, adding a physical Ground connection as described in post #126, connecting one transformer secondary lead to the physical Ground connection, and using a Siemens FS140 SPD at the load with its ground wire connected your physical Ground as described in post #126. Anything less is wishful thinking and hoping 'It's good enough'. Nothing is perfect, even with unlimited time and funds, I'm trying to come up with 'best practices' solutions that fit in your constraints.

Ok. But what I was asking was the following. The line to neutral lead in the Siemens FS140 was supposed to be connected to your US based phase and neutral of 120 volts. But in my case. I will put a 220v-110v transformer in my phase to phase of 240 volts turning them 120 volts. So my 120 volts now would be line to line (or phase to phase in your US language). Now I'm asking if I can connect the Siemens FS140 line to neutral leads to these 120 volts line to line output from transformer? Remember the line to line leads in Seimens FS140 was supposed to be connected to each of your 120 volts phase to create 240 volts.. but my secondary transformer line to line is now 60 volts to 60 volts so I can't use the line to line leads in the Siemens but phase to line which was supposed to be connected to your US phase to line of 120 volts... Remember the MOV inside the Siemens is 150Vac phase to neutral.. and 300Vac if two in series.. their line to line leads automatically has 300Vac MOVs and you can't use this for 120v output because the clamping voltage would be too high or mismatched... hope you get this subtle difference..

Now that this thread is in the Elecrical Engineering section maybe others can come up with better solutions.
(But of course by biased opinion is 'it's pretty darn good so far.' )

I think many of us learned a whole bunch of stuff throughout this project. I sure did!

Cheers,
Tom

 

[jim hardy]

I've not yet digested the seven pages.

Lookimg fpr a sketch someplace of how OP's system is earthed , if at all .. And the manual for that surge suppressor.

 

[kiki_danc]

Ok. But what I was asking was the following. The line to neutral lead in the Siemens FS140 was supposed to be connected to your US based phase and neutral of 120 volts. But in my case. I will put a 220v-110v transformer in my phase to phase of 240 volts turning them 120 volts. So my 120 volts now would be line to line (or phase to phase in your US language). Now I'm asking if I can connect the Siemens FS140 line to neutral leads to these 120 volts line to line output from transformer? Remember the line to line leads in Seimens FS140 was supposed to be connected to each of your 120 volts phase to create 240 volts.. but my secondary transformer line to line is now 60 volts to 60 volts so I can't use the line to line leads in the Siemens but phase to line which was supposed to be connected to your US phase to line of 120 volts... Remember the MOV inside the Siemens is 150Vac phase to neutral.. and 300Vac if two in series.. their line to line leads automatically has 300Vac MOVs and you can't use this for 120v output because the clamping voltage would be too high or mismatched... hope you get this subtle difference..

If my description was vague since I'm not a native.. here's an illustration:

You are to connect the line 1 and line 2 leads of the Siemens to each of the 120 Vac power wire making up 240volts... but what if you put 220v-110v step down transformer in phase to phase ac supply wires turning it into 110 volts.. then you can't no longer use the same line 1 and line 2 leads in the transformer output of 120 volts because the MOV in series is rated at 300Vac.. you are supposed to connect now the Line 1 and neutral to the 120v output of the transformer (that has phase to phase input) right?

 

[Tom.G]

Now I'm asking if I can connect the Siemens FS140 line to neutral leads to these 120 volts line to line output from transformer? Remember the line to line leads in Seimens FS140 was supposed to be connected to each of your 120 volts phase to create 240 volts..

Yes. Connect the Neutral lead of the FS140 to the wire that goes to the Grounded secondary terminal of the transformer. The Line leads of the FS140 get connected together then to the wire that goes to the other transformer terminal. And of course the FS140 Ground wire goes to your newly installed Safety Ground.

Lookimg fpr a sketch someplace of how OP's system is earthed , if at all .. And the manual for that surge suppressor.

@jim hardy
There was only one sketch shown that indicated IF there was a Neutral (Center Tap) on a 240V line then that would be Grounded. The OPs experience relating to getting a shock when contacting the 'Neutral' and a concrete wall indicates no Ground reference of incoming power.

the manuals were found with: https://www.google.com/search?&q=siemens+fs140+manual
They are: https://w3.usa.siemens.com/us/internet-dms/btlv/PowerDistributionComm/PowerDistribution/docs_EABU%20docs/TPS3_09.pdf
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43430
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43434

Cheers,
Tom

 

[kiki_danc]

Yes. Connect the Neutral lead of the FS140 to the wire that goes to the Grounded secondary terminal of the transformer. The Line leads of the FS140 get connected together then to the wire that goes to the other transformer terminal. And of course the FS140 Ground wire goes to your newly installed Safety Ground.

If you connect line 1 and line 2 of the Siemens to the 2 output of the transformer.. then the MCOV would still be 300Vac.. it's too high for 120 volts output... to force it to use the 150Vac MCOV MOV... the line 1 and neutral must be connected to the output of the transformer.. why can't this be done? This is to make sure you only have 150Vac MCOV used...

@jim hardy
There was only one sketch shown that indicated IF there was a Neutral (Center Tap) on a 240V line then that would be Grounded. The OPs experience relating to getting a shock when contacting the 'Neutral' and a concrete wall indicates no Ground reference of incoming power.

the manuals were found with: https://www.google.com/search?&q=siemens+fs140+manual
They are: https://w3.usa.siemens.com/us/internet-dms/btlv/PowerDistributionComm/PowerDistribution/docs_EABU%20docs/TPS3_09.pdf
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43430
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_43434

Cheers,
Tom

 

[Tom.G]

The FS140 is a type 2 SPD, it doesn't clamp the voltages as low as a type 3 because it is rated at a higher current. Note the rated voltage L-N (MCOV) is 150V, for a 120V supply. Your 24VDC supply is rated for 300V for a 5 sec. surge.
I thought this was a temporary installation of the FS140 at the protected equipment while you were finding a type 3 you were happy with. It's still better than nothing until you get a type 3.

 

[kiki_danc]

The FS140 is a type 2 SPD, it doesn't clamp the voltages as low as a type 3 because it is rated at a higher current. Note the rated voltage L-N (MCOV) is 150V, for a 120V supply. Your 24VDC supply is rated for 300V for a 5 sec. surge.
I thought this was a temporary installation of the FS140 at the protected equipment while you were finding a type 3 you were happy with. It's still better than nothing until you get a type 3.

No. Transformer setup is supposed to be a permanent solution because clamping voltage of type 3 is same as type 2.. the lower figure of strip surge protector you saw at amazon is because it uses UL 1449 second edition test vector which uses 6000 volts and 500 ampere only while UL 1449 third edition use 3000 ampere... but if all will use same third edition, result is the same... clamping voltage is dependent on MCOV only and not the surge current rating.. the following is example of a type 3 that uses third edition test vector and it still has 1100 volts clamping voltage.

http://www.tslpro.com/en/ka-type--surge-arrestor-58.html

 

[kiki_danc]

No. Transformer setup is supposed to be a permanent solution because clamping voltage of type 3 is same as type 2.. the lower figure of strip surge protector you saw at amazon is because it uses UL 1449 second edition test vector which uses 6000 volts and 500 ampere only while UL 1449 third edition use 3000 ampere... but if all will use same third edition, result is the same... clamping voltage is dependent on MCOV only and not the surge current rating.. the following is example of a type 3 that uses third edition test vector and it still has 1100 volts clamping voltage.

http://www.tslpro.com/en/ka-type--surge-arrestor-58.html

View attachment 231683

I knew since 5 days ago that clamping voltage is dependent on MCOV only and not related to surge current rating. this was the reason why we discussed all these transformers options because it's supposed to be permanent.. the simplest would be to get the following 150Vac module and connect it to my transformer 110v output...

But I want to try other US brand (prosurge is made in china).. this was why I was asking how do you connect the Siemens to the transformer t to make use of the one 150Vac MOV only. if you will connect the line 1 and line 2 to the transformer output of 120 volts.. you will still have MCOV of 300Vac inside the Siemens.. any idea? Because if not possible then I have no choice but to get the above..

Of course if type 3 with lower surge current indeed have lower clamping voltage.. then of course i'll get a type 3...

 

[kiki_danc]

Can anyone prove that clamping voltage is related to surge current rating? I think it's primarily connected to MCOV only.. the following is a background brief about it from a GE SPD page:

http://apps.geindustrial.com/publibrary/checkout/DEQ-155?TNR=FAQs|DEQ-155|PDF&filename=DEQ-155 - SPD FAQs.pdf

"What are some of the pitfalls when comparing clamping
voltage ratings between SPD manufacturers?

A: The task of comparing clamping (let-thru) voltage ratings
between SPD manufacturers’ published data, may initially
be perceived as a routine process. However, clamping
voltage can be one of the more ambiguous of all SPD
ratings. In simplifi ed terms, SPD clamping voltage can be
defi ned as the peak let-through voltage the SPD will allow
for a given surge test wave. Most SPD manufacturers will
publish average clamping performance data for their
various design types, and almost all will publish this data
while referencing one or more of the surge test waves
that are defi ned in IEEE Standard C62.41. While the reference
to C62.41 is valid, it sometimes leads customers
and specifi ers to believe that IEEE 62.41 is a standard that
provides a defi nitive testing methodology for the purpose
of determining SPD performance ratings. Unfortunately,
this is not the case, as IEEE C62.41 only defi nes the
surge environment and suggested test waveforms for
the various surge risk locations. The absence of a uniform,
industry accepted test plan leads to a variety of testing
methods that can be as unique as the manufacturers
themselves. For instance, some manufacturers may
measure the clamping voltage directly at the connecting
terminals of the SPD, whereas others might measure
with 6” or even longer leads. Others may omit critical
components such as an integral disconnect or fusing.
Any one of these practices can dramatically affect test
results. When comparing clamping voltage data, it is
always a good idea to request certified reports that
describe the construction of the test samples and detailed
testing methodologies. This will provide a better understanding
of expected performance when comparing
SPD types."

Tom, what do you think? I was thinking of using the Line 1 and Neutral lead of the Siemens to connect to the transformer 120v output to make use of the 150Vac.. but I forgot the Line 2. If it would not be connected then the unit would keep alarming.. so I guess this option may not work. Is there no way to trick the unit into using Line 1 and neutral leads only?

But if I can find technical literature and proof that clamping voltage is dependent on surge current rating, then surely I'd just get the 5kV type 3 only but then transformer from 220v to 110v is still required isn't it?

Does this mean for those countries with 220volts.. they always use 110v step down transformers in the equipment to get lower clamping voltage?

 

[kiki_danc]

Tom and other EE. I have spent 1.5 hours googling for the reference that VPR is controlled by surge current rating but can't seem to find it.. for example the following are bonafide type 3 device:

https://www.leviton.com/en/docs/Q-655G_Surge_Protective_Devices_BR.pdf

You will notice that the VPR are all the same.. Notice the 36kA has even higher VPR of 700V compared to the 84kA 600V. This when pulsed with a surge of 6000Volts and 3000 ampere UL 1449 third edition test vector..

So I'll wait for your comment first about theoretical arguments why VPR may still be related to surge current capacity rating. Maybe if the pulse is only 2000 volts and 300 ampere, the clamping voltage of lower current surge capacity will be lowered? Is there proof for this?

This is the most important variable before I decide whether to get a low surge capacity type 3 or moderate surge capacity type 2 to be put at equipment. The reason I prefer type 2 at equipment is because only quality brands have type 2 SPD and thoroughly tested while most type 3 amazon power strips are not quality tested well enough.

 

[jim hardy]

So I'll wait for your comment first about theoretical arguments why VPR may still be related to surge current capacity rating. Maybe if the pulse is only 2000 volts and 300 ampere, the clamping voltage of lower current surge capacity will be lowered? Is there proof for this?

Surge testing in my day was done using a source with specific impedance that delivered a decaying sinewave voltage surge
about 1973 it was simply called IEEE SWC ---- probably it's what became ANSI C37.90 ?
anyow the surge voltage could force a calculable current through that impedance
so perhaps my basic understanding of the question at hand is warped by old prejudices.
Volts is Joules per Coulomb
so
to get from a Volt rating to the Joule rating of a suppressor
one would have to multiply Volts by Coulombs and he'd wind up with Volt-Amp-Seconds = Joules.

Amps will likely be not straightforward to calculate

Trying to relate a voltage rating to current i think would require some knowledge of the source impedance assumed, and I'm as yet unfamiliar with the present day standards and how they were derived.

I do know the 1970-ish IEEE SWC of my day came about when solid state first made its way into switchyard protective relaying.
As you can imagine, interrupting kiloamps makes large di/dt transients hence significant dΦ/dt transients,
and those dΦ/dt 's induce amazing transient voltages in the wires that interconnect protective relaying.
But since they're coupled through air the 'source impedance' is considerable.
So IEEE actually went out to some switchyards, measured some transients,
and came up with a "IEEE SWC Test Generator" that produced similar voltage and current waves typical of those they'd captured ..
Here's a description from my day

Control Technology International, Inc.
15468 East Hinsdale Circle
Centennial, Colorado 80112-4225 USA
Phone: (303)-400-0547 Fax: (303)-400-0571 Toll Free: 1-888-CTII-USA
WorldWideWeb: www.ctii-usa.com Email: ctii@ctii-usa.com

The Oscillatory and Fast Transient (SWC) Test Specifications2.2 Oscillatory (SWC) Test Wave Shape and Characteristics. The oscillatory SWC test wave is an oscillatory wave, frequency range of 1.0 MHz to 1.5 MHz, voltage range of 2.5kV to 3kV crest value of first peak, envelope decaying to 50% of the crest value of first peak in not less than 6 ms from the start of the wave. The source impedance shall be from 150 to 200W. The test wave is to be applied to a test specimen at a repetition rate of not less that 50 tests per second for a period of not less than 2.0 seconds. (All voltage and time values refer to the open circuit condition of the generator.)2.3 Fast Transient (SWC) Test Wave Shape and Characteristics. The fast transient SWC test wave is a unidirectional wave. Its rise time, from 10 to 90 % shall be 10 ns maximum. The crest duration above 90% shall be at least 50 ns. The decay time, from crest to 50% of crest value, shall be 150 ns +/- 50 ns. The crest voltage is between 4kV and 5kV, open circuit. The source impedance during the initial rise time is 80 ohms or less. The test wave is applied for not less than 2 seconds at a repetition rate of not less than 50 pulses per second. Pulses of both polarities are to be applied. (All voltage and time values refer to the open circuit condition of the generator

That's just me refreshing the old gray cells . I still have pages of your thread to digest.
Meantime i found and saved this presentation to get myself more current(no pun intended) on the subject
file:///C:/Users/Owner/Downloads/IEEE%20Surge%20Protection%20Presentation.pdf

EDIT SOURCE - beware, this stupid IEEE link doesn't open a page , it directly downloads the presentation to your C drive without asking !

perhaps some of you IEEE members can access the standards it references.
and tell IEEE for me
"Gentlemen do not write on other gentlemen's computers without permission!"

So while i know this post hasn't really contributed to the thread , and i apologize for that

thanks for tolerating an old guy trying to get himsellf up to where he can help. I've jotted down the links here for my own reference but if they help anybody else I'm overjoyed.

Been a lot of progress in the last fifty years, i'd say. I have miles to go before i speak on this topic...

http://apps.geindustrial.com/publibrary/checkout/DEQ-155?TNR=FAQs|DEQ-155|PDF&filename=DEQ-155 - SPD FAQs.pdf

emphasis mine - jh
Q: What are some of the pitfalls when comparing clamping voltage ratings between SPD manufacturers?
A: The task of comparing clamping (let-thru) voltage ratings between SPD manufacturers’ published data, may initially be perceived as a routine process.
However, clamping voltage can be one of the more ambiguous of all SPD ratings.
In simplified terms, SPD clamping voltage can be defined as the peak let-through voltage the SPD will allow for a given surge test wave.
Most SPD manufacturers will publish average clamping performance data for their various design types, and almost all will publish this data while referencing one or more of the surge test waves that are defined in IEEE Standard C62.41

What I'm taking away from this is the science of surge protection is still largely empirical.

 

[Tom.G]

Yes. Connect the Neutral lead of the FS140 to the wire that goes to the Grounded secondary terminal of the transformer. The Line leads of the FS140 get connected together then to the wire that goes to the other transformer terminal. And of course the FS140 Ground wire goes to your newly installed Safety Ground.

If you connect line 1 and line 2 of the Siemens to the 2 output of the transformer.. then the MCOV would still be 300Vac.. it's too high for 120 volts output... to force it to use the 150Vac MCOV MOV... the line 1 and neutral must be connected to the output of the transformer.. why can't this be done? This is to make sure you only have 150Vac MCOV used...

this was why I was asking how do you connect the Siemens to the transformer t to make use of the one 150Vac MOV only. if you will connect the line 1 and line 2 to the transformer output of 120 volts..

Read the bolded parts above. They all say the same thing.

Of course if type 3 with lower surge current indeed have lower clamping voltage.. then of course i'll get a type 3

Read the specs for the type 2 and the type 3 and compare the clamping voltages at the same currents, then make your decision.

Cheers,
Tom

 

[kiki_danc]

Read the bolded parts above. They all say the same thing.

Yesterday I was analyzing this sentence of your for half an hour "Yes. Connect the Neutral lead of the FS140 to the wire that goes to the Grounded secondary terminal of the transformer. The Line leads of the FS140 get connected together then to the wire that goes to the other transformer terminal."

So let me take this opportunity to clarify. When you said "The Line leads of the FS140 get connected together".. did you mean Line 1 and Line 2 are shorted together and connected to one lead of the secondary.. while the other lead is connected to neutral (and the center lead to ground)? But won't the Siemens sound fault alarm if line 1 and line 2 are shorted??

Read the specs for the type 2 and the type 3 and compare the clamping voltages at the same currents, then make your decision.

Cheers,
Tom

Clamping voltage seems to be the same for type 2 and type 3 given the same pulse of 6000V and 3000Ampere. I'm looking for a theoretical justification. Anyway I think the best power strip in amazon is this:

https://www.amazon.com/gp/product/B0009K66KY/?tag=pfamazon01-20

The spec is in the message earlier. It passed UL third edition test. So if the Siemens would detect fault if line 1 and line 2 is shorted like you asked, then I guess the solution would be this power strip to make use of the line to neutral MOV... the strip won't sound alarm. This is because I can't find individual MOV module like prosurge which is made in china.

 

[kiki_danc]

Yesterday I was analyzing this sentence of your for half an hour "Yes. Connect the Neutral lead of the FS140 to the wire that goes to the Grounded secondary terminal of the transformer. The Line leads of the FS140 get connected together then to the wire that goes to the other transformer terminal."

So let me take this opportunity to clarify. When you said "The Line leads of the FS140 get connected together".. did you mean Line 1 and Line 2 are shorted together and connected to one lead of the secondary.. while the other lead is connected to neutral (and the center lead to ground)? But won't the Siemens sound fault alarm if line 1 and line 2 are shorted??

Let me illustrate the above with the following image:

Maybe you meant connecting L1 and L2 of the Siemens to L1 and L2 of the transformer secondary and connecting the neutral to the center tap??

But then the MOV that would be engaged in the Siemens would be two 150Vac Mov making up 300Vac... so using it for 120 volts would produce too high clamping voltage.. I was asking if you could connect the L1 of the Siemens to the L1 of the transformer secondary and neutral of the Siemens to L1 of the transformer secondary?? That way you can engage only one 150Vac MOV of the siemens L-N connection.

Clamping voltage seems to be the same for type 2 and type 3 given the same pulse of 6000V and 3000Ampere. I'm looking for a theoretical justification. Anyway I think the best power strip in amazon is this:

https://www.amazon.com/gp/product/B0009K66KY/?tag=pfamazon01-20

The spec is in the message earlier. It passed UL third edition test. So if the Siemens would detect fault if line 1 and line 2 is shorted like you asked, then I guess the solution would be this power strip to make use of the line to neutral MOV... the strip won't sound alarm. This is because I can't find individual MOV module like prosurge which is made in china.

 

[kiki_danc]

Tom. Since you only surf a few moments in the evening.. let me ask this now so I can decide whether to get this:

If you really meant connecting L1 and L2 of the Siemens to L1 and L2 of the transformer secondary and connecting the neutral to the center tap (right?) as detailed in the message prior to this. Then there is this problem of using total of 150Vac+150Vac MOV since L1 to L2 in the siemens is 300Vac. I only want to use 150Vac MOV across L1 and L2 of the 220v to 110v step down transformer. Would the following work?

That is. The L(ine) of the Leviton power strip would be connected to L1 of the transformer secondary and the N(eutral) of the Leviton power strip would be connect to L2 of the transformer secondary (while the ground is either left hanging or connected to future ground line).. would this work?? Can this trick the L-N of the Leviton power strip to connect to L1 and L2 of the transformer secondary to limit it to 150Vac MOV across the 120 volts secondary transformer output? If yes. Then I'd buy this since the Siemens split phase circuit may not be tricked. Thank you.

 

[Tom.G]

did you mean Line 1 and Line 2 are shorted together and connected to one lead of the secondary.. while the other lead is connected to neutral

Yes.

(and the center lead to ground)?

What center lead?

But won't the Siemens sound fault alarm if line 1 and line 2 are shorted??

Unlikely from the product description

Regarding the Leviton 5100-PS you found at Amazon:
If you are comfortable with the 600V VPR its as good as any. If you are interested in 330V VPR look at the TSFA6A120V here: https://www.erico.com/part.asp?part=TSF6A120V
One reference I ran across (can't find it now) is the lowest UL rating is 330V, then in goes up 400, 500, 600...

Tom. Since you only surf a few moments in the evening..

Not quite so, more like 4+ hours; most of it lately looking up data for, or explaining to, you!

More to follow...

 

[kiki_danc]

Yes.What center lead?

.

The black wire in the center... but then if you short the L1&L2 of the Siemens leads and connect it to one of the blue leads.. then what do you connect to the 2nd blue lead? This was what I was trying to figure out yesterday for an hour.

Unlikely from the product description

Regarding the Leviton 5100-PS you found at Amazon:
If you are comfortable with the 600V VPR its as good as any. If you are interested in 330V VPR look at the TSFA6A120V here: https://www.erico.com/part.asp?part=TSF6A120V
One reference I ran across (can't find it now) is the lowest UL rating is 330V, then in goes up 400, 500, 600...

Oh.. I'd get the erico then.

Not quite so, more like 4+ hours; most of it lately looking up data for, or explaining to, you!

More to follow...

Thanks so much.

 

[jim hardy]

Edited source for that informative IEEE Surge presentation in post 143 , see cautionary note