Fire Damage Procedure

[bjenks]

Does anyone know if there is code or a process to follow for replacement of equipment damaged by fire? I have a customer who had a fire in the bedroom. It burned the paint off the panel, but the wires are still in the breakers. I am thinking that even if the inside looks good the thermoplastic could have been compromised. Instead of running all new cables there might be a standard procedure to replace some length of all the cables. Any thoughts? GC is just wanting me to design a panel replacement, but I am thinking there is more to do.

 

[waross]

That's a hard call from a distance.
In North america I would consider calling in the local inspector for a ruling.
In most areas the inspectors are seasoned experienced professionals who quite possibly have seen and assessed fire damage many times over the years.
If you are left to your own devices, may I suggest a megger test of all conductors exiting the panel before any of them are removed. It may not take much heat for the older flavors of Romex to compromise the insulation inside a pressure connector.
respecfully

 

[waross]

Hi;
Another suggestion if you have to go with the existing wiring.
In the event of visible damage the wires must be replaced.
However there may be hidden damage inside the box connectors.
You may wish to insist on cutting back the outer sheath of the Romex an inch or two to look for hidden damage in the connector clamping area. Insulation damage in the clamp area may be repaired with tape or spagetti tubing. This assumes that you are able to pull one or two inches of slack on all the cables.
It is up to you or an inspector to decide whether there has been any heat damage to the wires. We can't make that call for you.
respectfully

 

[bjenks]

I am bringing a Megger MI420 out to test the insulation of each conductor. I am thinking that there has got to be a length at which a torch on a wire will only carry the heat a certain distance to damage the insulation. I am thinking something like 6ft (but I don't know, thus part of my question). If it is 6 feet and lets say half the conductors fail the megger test, is there such thing asputting a large tap box in the attic? I would specify that all the romex be cut six feed from the load center and have new conductors ran from the tap to the breaker. I would hate to have a new run of romex ran to a receptacle. Wouldn't be so back if it was THHN in a conduit, but romex stappled to studs....

 

[BJC]

Check with your insurance company as well. IF you don't and use the same wire and breakers the next fire may all be on your nickle.

 

[waross]

I would expect the following chain of events, but your visual inspection may take precedence.

1. The fire burns the paint off the surface of the panel, but the wall-board protects the Romex cables.
2. The fire heats the panel sufficiently that the box connectors get hot enough so that the conductor insulation is softened and displaced inside the box connectors. This damage may be repaired if you can pull a few inches of slack in each cable.
3. The fire and or heat visibly damages the cable near the panel. Replace the cable to the proposed pull box in the attic.
4. The heat is conducted down the cable for some distance and does further damage to the cable internally. First there will be more damage in the area of the panel than you describe. However, stripping the cable back and visually inspecting should get you into good cable that can be spliced in the proposed pull box.

If any cables fail the megger test, you may want to try stripping the outer covering off the Romex where it passes through the box connectors and inspecting for pressure displaced insulation. If the box connectors have been disturbed, a megger test may not show damage even though damage may be present. If any cables fail the megger test and inspection shows insulation displacement (squashed insulation) I would suggest repairing all of the cables. If the fire was localized on one side of the panel you may be able to repair only the cables on that side of the panel.
It would be well to protect your position by involving an electrical inspector and/or an insurance adjuster, as is suggested by BJC.
You must understand that we may suggest that you replace or repair everything but liability concerns and professionalism prevent us from declaring that an installation that we have not witnessed is safe to use.
This is free advice and is worth what you pay for it.
The final responsibility is yours and any local inspectors that may become involved.
It is my understanding that this forum is not for homeowners or do-it-yourselfers, but some moderators are quick to pull the trigger on any residential related problems even if professionals are involved. This thread may disappear Monday.
respectfully

 

[bjenks]

Good advice... I was hired by an insurance consultant for the electrical as I am a electrical PE. Already have a call into the local inspector. I would never hold anyone accountable for free advice. Thanks for your help.