Flooding Recovery Guidelines

Ravenvalor

Ravenvalor

Senior Member
Location
Triad region of NC
Occupation
Electrician
Good Morning,

I have a customer with a small business that received an unwelcome guest last Sunday, about 5' of water due to tropical storm Chantal here in Chapel Hill, NC.

The sheetrockers are removing the bottom 6' of sheetrock so that it can be replaced and the inner walls can be dried out.

I was wondering if anyone on this forum could give me some guidelines as to what electrical components should be replaced and what can just be allowed to dry?

The building is in a strip mall that was built in the 70s. However this little business was rewired in 2013 due to another flooding event.

If there is EMT or MC cable involved does that need to be replaced or can it be dried out? If drying is an option can I just point fans at the MC cable to speed up the drying? If it is EMT, can I use a vacuum cleaner to pull the water out of any horizontal sections?

If the EMT has THWN in it I should be able to verify that in the panel. But if the MC cable has THWN or something with a W in the name on it should I be able to see that in the panel?

I left a message with the electrical inspector late Friday for his advice but would like to go beyond what is just necessary.

Thanks for the great advice.
 
Following super storm Sandy which devastated parts of NJ we construction officials were given these guidelines by the state regarding flooded electrical systems.
Sandy Repairs.JPG
 
Our guidelines are pretty much the same as Rob's.

As far as the paper being wet, millions and millions of feet of NM has been in the back of open pick up trucks getting rained on and sitting in puddles before being installed, nothing to worry about.
 
Not sure how many have been involved with water damage remediation but I have seen many pieces of equipment and wiring that have been exposed to complete submersion or flooding from leaking pipe or roofs.
Seen complete submersion of residential panelboard that no breaker tripped energized the whole time while submerged.
Seen post submersion breakers as well as water intrusion non-submersion that while they may have eventually dried out internal failures was significant, rust, mechanical operation failures, corroded internal wire, etc. Seen "fully operational" (power still going trough) QO breakers that had water still present in the trip window, and rust stains coming out of the breaker seams.
Seen water intrusion in NM wicking more than 20ft uphill from the submerged end of the wire. Wire wet 5 years from the time of submersion, corroded grounds.
Flood water, fire suppression flooding, sewage flooding even fresh water burst pipe flooding present hazards of contaminant intrusion and corrosive implication. NEMA recommendations have valid considerations even "if" not "enforceable".
 
Fred B said:
Not sure how many have been involved with water damage remediation but I have seen many pieces of equipment and wiring that have been exposed to complete submersion or flooding from leaking pipe or roofs.
Seen complete submersion of residential panelboard that no breaker tripped energized the whole time while submerged.
Seen post submersion breakers as well as water intrusion non-submersion that while they may have eventually dried out internal failures was significant, rust, mechanical operation failures, corroded internal wire, etc. Seen "fully operational" (power still going trough) QO breakers that had water still present in the trip window, and rust stains coming out of the breaker seams.
Seen water intrusion in NM wicking more than 20ft uphill from the submerged end of the wire. Wire wet 5 years from the time of submersion, corroded grounds.
Flood water, fire suppression flooding, sewage flooding even fresh water burst pipe flooding present hazards of contaminant intrusion and corrosive implication. NEMA recommendations have valid considerations even "if" not "enforceable".
Click to expand...
I have been involved with flood restoration for years (look up Hurricanes Idalia and Helene for a couple recent examples) and as far as wire is concerned, I will say NEMA is looking out for manufacturers interest. With that said, I will say that Aluminum is not the same as Copper and should be addressed. I know of NM that was submerged more than 30 years ago and in service everyday with no problems.
 
One concern is whether the place has dried out before you get there. If you want to salvage some things, they're much easier to rinse out with clean water when they're still wet; once any muck is dry, it's much harder.

Also, figure in what insurance is willing to pay for - if they say "replace all the receptacles and switches", just do it.
 
The inspections department in Chapel Hill is making us replace the MC cable that was submerged.
Not a big deal for my customer, he only has 7 - receptacles that were submerged.

Thanks for the great input.
 
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