Generator causing AFCI's to trip ...?

[flatlander]

Power was restored today; customer called and said all the breakers are still tripping. Sounds like they got fried. The surge breaker is also out, and I was told two TV's let the smoke out. They're all on P&S TVSS receps also. I think they got a pretty bad surge.


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Did the smoke let out when the power was restored or the other day?

 

[peter d]

Generator waveform is being mistaken as an arc fault to the breakers. Nothing more into it.

:thumbsup:

Dirty power wreaks havoc with AFCI's. Anything that looks at waveforms is going to go nuts especially cheap garbage AFCI's.

 

[brantmacga]

Did the smoke let out when the power was restored or the other day?

He just told me today it happened during the storm.



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[brantmacga]

:thumbsup:

Dirty power wreaks havoc with AFCI's. Anything that looks at waveforms is going to go nuts especially cheap garbage AFCI's.

Are you saying the QO's are cheap or all AFCI's in general ?

I know a lot of people have issues with them; I just rarely do. This is the first time I've lost any to surge that I'm aware of. The replacement cost is the biggest downside. I did all I could to protect them though with the surge breakers, and I do extensive grounding with CCE's and additional electrodes.


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[peter d]

Are you saying the QO's are cheap or all AFCI's in general ?

I know a lot of people have issues with them; I just rarely do. This is the first time I've lost any to surge that I'm aware of. The replacement cost is the biggest downside. I did all I could to protect them though with the surge breakers, and I do extensive grounding with CCE's and additional electrodes.

I can't speak for QO as I don't use it. But I know that any kind of dirty power whether it's from a generator or other off-grid source, or any dirty power interference on the grid can and will cause nuisance tripping and damage to AFCI's.

 

[JFletcher]

What model and size generator? I've heard (but not confirmed) that some generators and inverters use like a 60-0-60 volt setup to get 120V; two 60V hot legs 180* apart to get 120V. Connecting appliances via extension cord works fine, but connecting to a panel would cause immediate and severe problems.

 

[GoldDigger]

What model and size generator? I've heard (but not confirmed) that some generators and inverters use like a 60-0-60 volt setup to get 120V; two 60V hot legs 180* apart to get 120V. Connecting appliances via extension cord works fine, but connecting to a panel would cause immediate and severe problems.

That is commonly done in cheap Modified Square Wave (MSW) inverters to minimize the voltage to ground that the output power elements have to withstand. Some power converters in RVs are also built that way.
Connecting "neutral" to EGC will lead to equipment chassis riding at 60V and/or letting out all the magic smoke.

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[mbrooke]

Are you saying the QO's are cheap or all AFCI's in general ?

I know a lot of people have issues with them; I just rarely do. This is the first time I've lost any to surge that I'm aware of. The replacement cost is the biggest downside. I did all I could to protect them though with the surge breakers, and I do extensive grounding with CCE's and additional electrodes.


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All resi grade AFCIs (BR, CH, QO, GE, Siemens, Murray, ect) lack the computing power necessary to discriminate wave forms.

 

[mbrooke]

Power was restored today; customer called and said all the breakers are still tripping. Sounds like they got fried. The surge breaker is also out, and I was told two TV's let the smoke out. They're all on P&S TVSS receps also. I think they got a pretty bad surge.


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Sounds like a power surge. During storms its not uncommon for high voltage lines to crash into low voltage ones, ie 7,200 volt primary crashing into a 120/240 secondary or a 69kv sub-transmission circuit falling into a 12.47kv distribution circuit causing some serious and sustained over voltage to all transformers connected to the 12.47kv circuit.

Also, Id megger a few circuits just in case. Inspect the breaker panel. I know this surge looks bad, but trust me, people have experienced far worse. In one case a 20kv ended up being placed on the home's wiring. In the end the whole home needed to be re-wired because it damaged the insulation on the NM and arced out the panel bus bar. Ever single appliance was also toast. Customer has it lucky on this one.

 

[Ragin Cajun]

Regarding surges, etc. I have found the most effective protection is an external surge arrestor. Mine is in a 4 x 6 10" box mounted on the service disconnect. The quality ones are expensive, but worth the cost. Keep the leads short.

RC

 

[brantmacga]

Here's an update guys ....

I went back out today; the AFI's are definitely damaged. And I have a couple of TVSS recep alarms going off, and two surge breakers are out.

I was told today that a tree fell on an REA distribution line and brought it down on top of their Georgia Power line.


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