GFI Caused a Fire!

[a]

My neighbor just suffered a serious fire. His house had an enclosed porch at the rear, with an open, roofed desk connected to the porch rear. He had several GFI breakers out there, including one on the rear porch wall. Around one AM, when he and family were asleep, a fire started at that GFI switch (according to Fire Marshall), and got going pretty good before their dog started barking. That saved their lives for sure. Almost killed their dog and cat, though. The fire badly burned the rear half of the house and sent black soot throughout the rest of the house. The house is pretty well totaled.

That's what happened. I have to wonder how a GFI could do that! I heard the Fire Marshall actually say that what happened was the GFI wires arced, but that was not a 'short' to the GFI. Hence it didn't trip. So, the GFI presented no protection did it! The arcing just continued until it started the fire!

All this makes me think that my GFIs are not providing me the protection I always thought they did. I'm not sleeping as well these days.

Anyone have an opinion about this?

Thanks

me

[RBM]

GFCI devices don't provide short circuit protection. They provide ground fault protection. The device that would have, should have prevented this is the circuit breaker, or better still, an arc fault circuit breaker

[thekmanrocks]

Now the question is, did that GFCI preclude the circuit breaker's ability to do its job?

[John Grabowski]

*I surmise that the GFI receptacle had loose connections and that there was a considerable load on the wiring. That would cause the arcing which would ignite any combustible materials in direct contact or in very close proximity.

As RBM pointed out the GFI is not designed for this type of protection, but an arc fault circuit breaker is.

Does this house have smoke detectors?

[Tomsic]

Right, the usual GFCI does not against electrical arcs. The National Electrical Code now requires arc fault circuit interrupters (AFCI) in certain rooms of homes to reduce such fires. Wikipedia has a good summary of what GFCIs can and cannot do at:

Arcing that results from loose connection at outlets and switches or broken wires are a major cause of house fires.

Tomsic

[micky]

So it seems like the ground fault is especially useful near water faucets and wet places.

But the arc fault seems especiallly useful everywhere, not just bedrooms. Does that mean every circuit breaker should be arc fault?

[bud--]

And if that is what happened the GFCI wasn't any more responsible for the fire than if the same thing happened with an ordinary receptacle.

I wonder how much of the GFCI was left for the fire marshal to determine what happened.

[DerbyDad03]

Now I'm really going to burst your bubble.

You know all those years you were sleeping well because you thought your GFCI's were protecting you against a short and/or a fire? Well, you shouldn't have been sleeping that well because a GFCI won't do either.

You really should read up on how GFCI's work and what they do and don't protect against so that you are not living under incorrect assumptions.

[a]

Yes. Though he never mentioned that one went off. Seems like a detector should have detected all that smoke. Maybe he had detector(s) in the house proper, but not on the porch enclosure on the rear. The smoke did not get into the house until he actually opened from the inside of the house one of the sliders from the house onto the porch, at which time the sliding doors actually exploded and blew into the house. At that point the black smoke inundated the house proper. So I'll bet he had no detector on the porch. I'll have to ask. Now that I think about that, I don't either. My enclosed sun porch was built after the house. As soon as I can, I am going to add one to my porch for sure.

me

[a]

It was there. I saw it - together with his written report hanging from it. I saw it too.

me

[recyclebinned]

1. Did the fire start inside the electrical box of the GFCI or a circuit coming or leaving it?
2. Was the electrical box metal or plastic and was it in a wet location and if so was it an outdoor box?
3. Was the line connected to the box Romex or was it inside a conduit and if it was inside a conduit was it a EMT or rigid or PVC and was it in a wet location?

[John Grabowski]

*Article 210.12 in the 2011 National Electrical Code requires them for almost every circuit in a home.

[The Daring Dufas]

Yep, the four legged type that barks. ^_^

TDD

[a]

That's great for new houses. But my house was built back in 1998.

me

[The Daring Dufas]

I believe arc fault circuit breakers could prevent fires in homes with aluminum Romex. I've heard sizzling inside many junction boxes in many homes wired with aluminum Romex. O_o

TDD

[a]

or leaving it?

I don't know

so was it an outdoor box?

plastic box not in a wet location (was on the wall between the porch addition and the roofed open deck behind it)

was inside a conduit was it a EMT or rigid or PVC and was it in a wet location?

I don't know. I'll bet Romex, not in conduit.

Your questions are all germane to the issue and certainly should be answered. Thanks for response. me

[Tony Hwang]

Hi, My first impression, where is fire/smoke detector? Poor install(stab wiring?) cheap GFCI product? Overloaded circuit? Thank the dog, it could be worse.

[RBM]

I don't advise trying to use current technology on older wiring systems. Aside from Edison circuits, you find anomalies caused by mixed neutrals and the like. You certainly could test each circuit with an AFCI, and if it holds, you're good to go

[bud--]

You can likely add them one way or another. If circuits are multiwire branch circuits with a common neutral that is a problem.

[micky]

Even after looking it up last year, I never did understand what an Edison circuit is or how it's different from any other circuit.

I know approximately what a mixed neutral is. I don't think my home described below is likely to have the anomalies you speak of.

My house is from 1979, has quite a bit of empty space in the breaker box, and there has only been one change, one added circuit, to the attic to power the attic ceiling light (with receptacle), the roof fan, and the outdooor floodlight. Along the way it goes by the far wall of the laundry room where it powers a ceiling light and 5 double receptacles (no more than 2 sockets are used at any one time, a lamp and one power tool or another.) The circuit breaker has never tripped.

Do you think it's likely I'll have problems changing to AFCI?