[crknjk]

Long time lurker, 1st time poster.

Story Background. A client of mine lost a few appliances and TVs during an a storm a while ago. I suggested a whole house surge in the the panel. This is a patio home complex with one underground service feeding a four gang meter bank.
Each unit has a 100-amp disconnect on meter bank. Panel inside is a Siemens so i install a Siemens QSA2020SPD.

In October they call and said they are having issues with the SPD after a bad storm. Sure enough the SPD breakers won't reset. I remove the SPD and see that it toast. Has cracks in molding, residue on neutral wire. They lost a Keurig. The breakers on the SPD protect the small Appliance circuits. I explain the SPD did its job and they could have lost a lot more. Turns out a lot of people in the complex lost a lot of appliances during the storm. No one in their 4 unit complex lost anything except them. I end up installing 10 QSA2020SPD throughout the complex. utility states a tree fell on a line and there is nothing they can due.

Yesterday the area had a bad wind storm, no lightening The same client calls and says their SPD is not working. Check it out and its toast again and they lost another Keurig.

So now I am wondering are these SPD's junk and I need to install better ones?

Is it the fact that they are technically in a subpanel a problem even though there are no other circuits in any other panels?

Why is this client receiving the brunt of these surges?

Any thoughts?

 

[Dennis Alwon]

If the Keurig is part of a small appliance branch circuit then it is possible you have a sporadic problem with the neutral.

If this happens with wind then my guess is the power company has an issue with it's neutral somewhere along the lines-- especially if the wires are overhead.

 

[splatz]

I hadn't seen this device before, whole house surge and a breaker in one. Square D has a SPD that goes right on the bus but if I remember right you just wind up with a dead spot on the panel, it isn't a breaker too.

I partly like the idea of a SPD that goes right on the bus. You don't have to buy a breaker to connect it to. Can't get much easier to install. They say keeping the leads short with the SPD is important, they can't get any shorter than a direct attachment to the bus.

However on the other hand, since a bad surge can blow the SPD apart, I think I'd rather that thing melt down outside the panel. I don't want a device that saves my Keurig but destroys my panel.

It sounds like maybe the circuit you have connected to the breaker could be a shared neutral supplying the kitchen counter receps. I can't really connect the dots but I'd want to avoid a shared neutral circuit on this kind of combination breaker / SPD.

I'd actually rather not use the breaker on the SPD, I'd rather leave it unused, but if you are out of panel space and you have to, use that breaker for the circuits with the least used / least delicate / least valuable loads.

Looking at the specs for this device it starts clamping at 240V. I don't think the rise from 120V to 240V that comes from a loose / open neutral on the service or on a shared neutral circuit would get any response from the device.

The spec is for 360 joules line to N and 720 joules line to line which is pretty puny. A $20 point of use surge strip is usually 1000 joules and a $30 point of use is usually 3000+ joules.

As for why this unit is the only one that gets whacked - hard to say. Is there anything different about their ground electrode conductor / GES? Small differences in impedance could make them the sacrificial lamb. It could be something hard to pin down, their plumbing is different, they are closer to the pool, they are further from the pool, they are closer to the utility transformer, they are further from the utility transformer, marginal connection on the service conductors, etc. etc. etc.

 

[splatz]

If the Keurig is part of a small appliance branch circuit then it is possible you have a sporadic problem with the neutral.

If this happens with wind then my guess is the power company has an issue with it's neutral somewhere along the lines-- especially if the wires are overhead.

That makes sense especially since this SPD is also a two pole 20A breaker, but the rise to 240V (or 208V?) they'd see with an open neutral would barely make the SPD start to clamp down the surge ... but maybe with the sporadic neutral connection it would have a cumulative effect.

 

[Bird dog]

As for why this unit is the only one that gets whacked - hard to say. Is there anything different about their ground electrode conductor / GES? Small differences in impedance could make them the sacrificial lamb. It could be something hard to pin down, their plumbing is different, they are closer to the pool, they are further from the pool, they are closer to the utility transformer, they are further from the utility transformer, marginal connection on the service conductors, etc. etc. etc.

Also, are they near or at the end of the utility line?

 

[crknjk]

All services are underground. This was a pretty big wind storm. We have thousands of people without power, so I believe they may have been hit by a surge. Just wondering why they are so susceptible to them and how to help them out. I am thinking of talking to utility once things calm down and see if they will put a SPD on their meter. They have lost a lot of stuff while their neighbors on the same meter bank lose nothing. Unlucky I guess.

 

[Navyguy]

However on the other hand, since a bad surge can blow the SPD apart, I think I'd rather that thing melt down outside the panel. I don't want a device that saves my Keurig but destroys my panel.

I can't tell you how many times I have had this conversation... Sometimes I feel like a dummy because people just don't get it.

Cheers
John

 

[spaceman]

I think I'd rather that thing melt down outside the panel. I don't want a device that saves my Keurig but destroys my panel.

and

I can't tell you how many times I have had this conversation... Sometimes I feel like a dummy because people just don't get it.

I think you REALLY want that SPD to be INSIDE of the metal box that is your panel/load-center, so that in certain surge conditions, it reduces the risk of the house burning down. I nearly lost my home this way.

UL Labs even issued this warning after researching several house fires caused by whole-house SPDs:

We have researched the situation and have come to the conclusion that grounding is the issue. There has been potentially hazardous situations only in applications without proper grounding. Grounding is of utmost importance when it comes to surge protection. A high resistance to ground in a surge event, no matter the manufacturer or the application, can cause heat to build up in the surge device. We can not stress how important it is that upon installation of any surge device the ground be checked for quality.

Obviously, In the open-neutral condition, if the two poles are imbalanced, one side will be higher voltage and the other will be the complementary voltage (e.g. 185v on Red with 45v on Black). In this condition the SPD will blindly start dumping, dumping, dumping current on the high-side of the imbalance to the neutral bus (by way of a MOV or SASD component). The SPD isn't designed to carry high current for a long time, so they can overheat/melt, and even catch fire (as above). The main breaker won't trip (because that's an over-CURRENT device, not an over-VOLTAGE device). SPD fires happen, and the solution to surge protection (creating the risk of a house fire) is worse than the problem (having to buy new appliances/Keurig). It seems most sensible to least contain the hazard as much as possible in a closed steel box with restricted oxygen, NOT mounting on or near a flammable plywood backing board giving it plenty of fuel and oxygen.

 

[gpop]

I rent mine from poco and it comes with insurance that will replace any item damaged by lightning. They recently just upgraded or replaced it (tbh i did not really read the letter other then to tell the wife she would have to lock up the dogs on what ever date it was).
They also supplied smaller surge plugs for inside the house (not strips) that are still laying in a draw from 10-15 years ago.

I have taken many hits including one strong enough to blow the transformer and so far have not lost anything. To me personally $6 a month (fixed life time cost) was worth it for the insurance. As the suppressor is hidden behind the meter im not sure what it is or even if its working as long as they pay for replacements i don't really care.
Im not sure i would want a primary non-fused suppressor inside my home as i would rather deal with it on the shortest ground path and i believe a breaker is to dam slow to clear a mov once it goes terminal. As a second or third suppressor inline that probably would not be a problem.

 

[SWDweller]

I recommend the Soars Book on Grounding.

You must cover 2 of the 3 zones in your distribution. Service is fine, then one point of use.

When I worked for Eaton they freely admitted (internally) that the plug in models are not a robust as the exterior mounted models. Looking at the joules that each will handle makes it understandable. In this case more joules is better.
Most MFG's make or have made protectors, get the published data and make your choice.
Cheap is usually not the most protective.

Now for the really bad news, these devices are not forever. They are tested/listed for one punch.
There is no guarntee that the device you install will save the connected loads. It all depends on the surge. The how, and how close. Even if you have them installed at the service and the point of use the magic can be evaporated.
I have one on my service and another plug in one for my garage door opener, just ordered a new garage door opener and a new cable modem after the last monsoon we had roll through Southern Arizona.

 

[MikeFL]

Clamping voltage on a MOV is not going to clamp an imbalance due to bad neutral.

 

[spaceman]

The SPD isn't designed to carry high current for a long time, so they can overheat/melt, and even catch fire (as above). The main breaker won't trip (because that's an over-CURRENT device, not an over-VOLTAGE device). SPD fires happen, and the solution to surge protection (creating the risk of a house fire) is worse than the problem (having to buy new appliances/Keurig). It seems most sensible to least contain the hazard as much as possible in a closed steel box with restricted oxygen, NOT mounting on or near a flammable plywood backing board giving it plenty of fuel and oxygen.

I talked to Schneider / Square-D Level 3 Tech support today to inquire about the manner in which their SPDs fail in an over-voltage condition (such as the open-neutral or high resistance neutral). The agent stated that they're very aware that improperly made/un-fused SPDs can cause a fire when they dump (attempt to clamp) over-voltage to the neutral bus. He said that UL-1449 2nd Ed. SPD's are FUSED (e.g. the QO250PSPD and EPD80), effectively taking the SPD out of the circuit if it exceeds its current rating. The main idea being that a properly made, properly fused SPDs is at a decreased risk of causing a fire (compared to SPDs of the past). Thus, my concern about enclosing the SPD inside the panel (for increased fire safety) may be of minimal concern (for fused SPDs).