Electrical Overload?

Old 12-18-18, 06:37 PM
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Electrical Overload?

I figured you guys might like to see this. I don't have any background other than what's stated with the pictures, but it sure looks like someone did something wrong. Goes to show that there's a reason for code requirements

(More pictures and commentary in the link)

Old 12-18-18, 07:08 PM
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I see 2 breakers with 3 wires attached. That breaker is designed for maximum of 2 wires.
But this was not the cause of fire.
My guess is same as what he is guessing.

Current to ground probably ran to whatever was plugged to receptacle at the bottom because the panel was never grounded.
There must have been some path to ground to whatever was plugged in the receptacle and burned that as well.

The home owner is lucky nobody got electrocuted (at least it wasn't mentioned).

This would have been prevented if the panel was grounded. It will still fail, but at least the breaker will trip.
Old 12-19-18, 09:57 AM
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Maybe even a lightning hit or a primary to secondary short.
Old 12-19-18, 11:01 AM
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Looking at it again, I can see why the panel heated up if it wasn't grounded. But why the burn marks at the receptacle closer to floor level? Curious.
Old 12-19-18, 01:32 PM
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Wondering if the lower receptacle was GFCI and the box and conduit at 120v. Maybe internally neutral and ground are on the same circuit board and heated up?
Ignore this - looking closer the bottom receptacle is standard duplex.

Last edited by Astuff; 12-19-18 at 02:50 PM.
Old 12-19-18, 02:07 PM
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Not your typical homeowner install...... too much EMT. Homeowners rarely use conduit.

The little sub panel to the right with NM in MC connectors.
I see a few mysteries.... electric heater connected with MC but wasn't connected at the panel but is now hanging.
Old 12-19-18, 02:37 PM
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My guess is the sooty plastic goop got blown down all the conduit openings when the fire really started going. Probably caused some residual burning in all the downstream boxes.

The fact that it's not completely melted to slag and didn't burn the building down, it seems like a slower process like oxidation on the aluminum feeders building up a lot of heat until the plastic flashed over. If the incoming main shorted out, that liquifies the metal and burns all through the wall.

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