Surge Protectors for panelboards

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jaggedben

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Solar and Energy Storage Installer
We are installing more and more residential energy storage, which is expensive equipment. We're thinking of installing surge protectors standard with our installations to protect this equipment. We've had a handful of solar inverters get knocked out by surges. Most practical seems to the surge protectors made by the panelboard manufacturers that just plug on like a breaker. (These are AC coupled systems.)

I'm curious what your general thoughts and experiences are with these, and also whether they are sufficiently rated. For <$100 They seem to be rated at 50,000 amps, which I guess I don't really understand the meaning of in terms of what the likelihood is of a surge that size. We are just looking to prevent say 90 percent of the possible damage from surges without spending too much. I suppose I'll probably get as many opinions as replies, but what say you, are these worth it?
 
The bigger the surge protector, the more surge it can protect against before being used up. The ones that plug into the panel are convenient, but small. I use them because we are required by local ordinance to put a surge protector (of any size) in a new panel. Since big surge protectors increase the price of the job, I don't use them since most clients could care less about the surge protector. Most of them think it's snake oil. If you are really concerned about surges, use the biggest one you can afford.
 
And get one that tells you when the protection is gone, i.e. after it takes a big hit and does its job. At some point they will sacrifice themselves in the line of duty, but if you don't know that happened, you may as well not have one.
 
2020 NEC requires SPDs on dwelling unit services.
Mike Holt once said "you get what you pay for, more is better", about SPDs.
For 30 years, every electrical service I installed had SPD, for 480v, 2, one on the 480, one on the 120/240. After installing SPDs, I noted the power supplies on the electronics wete no longer failing.
The Leviton 42,000 and 32,000 had alarm contacts to indicate if the protection fails.
 
I remember when the surge protectors were rated in joules but apparently they no longer do that.

The 2020 nec does not specify a minimum protection so anything goes, I guess
 
Although I am vehemently against the NFPA finally giving in to Schneider's repeated and consistent attempts to get a surge suppression requirement put in the code, I have been installing the breaker type ones for PV systems I do.
 
Electronics are everwhere, SPD is a necessity. SPDS have been required for emergency systems and seems like one other article.
I kind of agree with you on the Schneider issue.
 
Guys, thanks for all the replies, but I guess I'm looking for some more quantitative and specific feedback on SPD products. This is kind of like insurance for us, we want a good price for decent coverage. Damaging surges will probably be rare but they'll be costly when they happen. Budget is not unlimited. Do you think 18kA protection is worth anything? Any idea the point at which it becomes cost effective?
 
jaggedben said:
Guys, thanks for all the replies, but I guess I'm looking for some more quantitative and specific feedback on SPD products. This is kind of like insurance for us, we want a good price for decent coverage. Damaging surges will probably be rare but they'll be costly when they happen. Budget is not unlimited. Do you think 18kA protection is worth anything? Any idea the point at which it becomes cost effective?
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And that's the thing. Most all of us agree that surge suppression is good to have, very few of us have an in depth knowledge of how it works and when we do come across someone who seems to have that knowledge we are reluctant to to trust them because they are usually trying to sell us something.

In my house I put the breaker style in the main panel (that was 2005 and the green light is still on), a blue Leviton surge suppressor (which I notice they don't sell anymore) receptacle at my entertainment center, and plugged a surge suppressing power strip that my AV guy recommended into that.

Most of the cell sites I've worked on don't have any kind of surge suppression, but they do have about ninety-thousand dollars worth of earth grounding.

Who knows.

Pick a product from an established, reliable supplier in your area and make a note of the date it was installed and in five years report back if it failed or not.
 
Not sure what you're looking to protect but would doubt 18ka would do much if anything for lightning strike energy, typical strike would be near 100ka if not more. To get total 100% coverage may be impractical for cost on typical residential service, but I've found one that gets real close, and at a comparable cost to the Schneider and Eaton surge available at the big box stores, but with much better rating, and Mfg in Virginia. the 1 below offered $100,000 equipment repair replacement if surge gets through and it was active at time.
1598139163442.png
They have one listed for both generator and utility power also. They also have larger capacity ones too. I put one of their H100 on a customer's house who was consistantly having surge take out the refrigerator circuit board, after installing, he's had surge events that normally wipes out his fridge and he's had no issue.

PSP Products,
Hurricane 2000 Series
100,000 Surge Amp Capacity Single and 3 Phase Surge Protection

Industrial Surge Devices that protect facilities from power surges

Industrial Surge Devices specially designed to handle the highest levels of surge activity found in the most demanding commercial and industrial facilities
www.pspproducts.com www.pspproducts.com
 
Thanks.
Protection from lightning would be good, but I think the more likely instance around here would be from the utility. Any idea what the size of those surges is likely to be?
 
jaggedben said:
Thanks.
Protection from lightning would be good, but I think the more likely instance around here would be from the utility. Any idea what the size of those surges is likely to be?
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If there are voltage surges from the utility large enough that the SPD is conducting, then I think it's likely they could have a long enough time duration that they'll exceed the energy dissipation capability of the SPD.
Someone here with utility experience like Hv&Lv might be able to chip in on likely POCO overvoltage and transient characteristics.

As described on pg. 5 of the document from Eaton linked below:

"TVSS are designed to prevent high energy, short duration (typically two milliseconds or less) transient voltages from causing damage to an electrical installation. TVSS are not designed to sustain long-term overvoltages."


So I think assuming that a typical SPD will reliably clamp utility overvoltages on the bus of the service panel may be expecting too much.

That being said, I think there could be some value in having a fused disconnect feed a subpanel for the inverters that has an SPD in it. That way under some overvoltage scenarios a fast acting fuse might open quickly enough when the SPD starts clamping that both the SPD and inverters would survive. Also, the "let through" voltage of SPDs is lower when there's more wire resistance ahead of them, which would be the case if the SPD is in a subpanel for the inverter(s). But without knowing what level and duration the overvoltages could be it's hard to say whether this would be effective.
 
jaggedben said:
Thanks.
Protection from lightning would be good, but I think the more likely instance around here would be from the utility. Any idea what the size of those surges is likely to be?
Click to expand...

Spending money on surge suppression is, of course, a gamble. In my 20 year electrical career, I only recall two instances ofl "surge damage." One was a family friend that had three appliances/electronics knocked out from a nearby lighting strike. The other was I heard reports of a house in my county badly damages by lighting, but I did not verify or investigate. Of course I dont mean to subscribe to the fallacy that If I dont hear about it, then it doesnt happen, and also there is the possibility of a surge shortening life of equipment without destroying it outright, but the point is it is quite rare.

For PV, and granted without much scientific basis, I feel that induced surges from nearby lighting strikes damaging inverters are the main concern.
 
Thirty years ago, SPD selection was extremely difficult and there was a lot of snake oil being sold. The joule rating was not consistent between manufacturers, so it was not a reliable method of comparing performance. Eventually the industry (e.g. IEEE C62.41-2002) settled on some typical waveforms (like those from switching capacitors, or near by lightning strikes) and UL developed some standard testing methods. This gave us the Type 1 (installed at the service location) and Type 2 (installed downstream from the service location) protection we have now.

Over the years I have found that most service entrance SPD, not plug-in style, are mounted incorrectly. Lead length and routing are extremely important important.

I used to use SPD products from a company called Transtector (they also make coax and data protection).This is a link to one of their white papers, on suppressor technology.
 
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