Flooded Insulated Electrical Wiring

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Old 04-30-19, 11:44 AM
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Flooded Insulated Electrical Wiring

OK. So I have a cottage on the Ottawa River and right now we are experiencing record flooding. As I speak, I have water in my crawl space right up to within 2 inches under my subfloor. The good news is they are forecasting that it has peaked. I will know if they are right in a few days and that would be very, very good news.

My question is about the electrical wiring in my crawlspace. The wiring for all the outlets and baseboard heaters, etc. moves along the joists and main beam holding up the joists, in the crawlspace. Of course, from what I have seen it is all insulated wiring. That wiring is currently submerged in water. The main power to that cottage was turned off days ago, long before any water was even in the crawlspace.

My question is would water that rose above insulated wire and then dropped back down, cause a problem with that wiring. This is an in general type question.

2ndly, if there was a wire that might have been spliced to another down there, that I never noticed, or a mouse ate away a little insulation, would it most likely just trigger a breaker, if it was still wet, or a fire. I am not planning on using any power until the water is way below that wiring but how dry it will be over the days after, will be a little uncertain.

The cottage is 24' x 36' with the center beam going down the 36' length. Wiring is on that beam and the joists above it. No outlets or appliances are in the crawlspace. I would believe all spliced wire would be above it all, inside the cottage, which hopefully receives no water. Fingers crossed.

Any help, suggestions or thoughts would be appreciated.
 
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Old 04-30-19, 12:11 PM
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There is an official standard for this: https://www.nema.org/Standards/Pages...Equipment.aspx

You have to create a free account to download the PDF.

The tl;dr version is that any "dry" type cabling (e.g. NM-B or NMD) cables should be replaced if they have been submerged. "Wet" and underground type cabling (e.g. USE, THWN, MNWU) can be re-used as long as the stripped ends were not submerged, otherwise replace. Breakers, switches, receptacles and similar devices should be replaced. Junction boxes should be replaced.
 
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Old 04-30-19, 07:52 PM
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Not sure if the same link as above or not.

https://www.doityourself.com/forum/e...equipment.html
 
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Old 05-01-19, 08:14 AM
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Thanks for that. I kind of thought the code approach would be "replace it all".

As we know, that statement is a lot easier to say then to do. Even if money was unlimited, in my case I have a couple of obstacles.

I would like to have power right away to get some fans going and to start drying things out. I think I have one outlet where the wire might be above the floor. The good news for my crawlspace is the opening for it is right near my breaker box. I can possibly create a few quick outlets to give me some new power for that.

The big problem is the crawlspace. It is not overly high. 2ft to 3ft at best. I cannot see me finding an electrician to go down there, crawl around and replace all that wiring. Most of their hourly rate will be used up crawling back and forth, if they were willing to do it at all, which I doubt. Add to that, right now it is a floor of wet mud that will probably not dry all that quickly.

I will need to lift this cottage up because we have now set a new flood plain level. So it would be nice to do that replacement job once it is about 3 feet higher. Unfortuneately I can't see that happening until the fall at the earliest and probably next year. I am far from alone with this flooding problem. The water levels were biblical.

Not sure how difficult it would be to re-wire the place all on the main floor. It is a bungalow structure, originally built in 1978. Most of the walls are panel board. There is insulation in the outer walls.

Any great ideas for me would be appreciated. Keep in mind, there is no insurance for river flooding, but that is my secondary concern to safety.
 
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Old 05-01-19, 08:49 AM
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It's really hard to say on the cable because they only test and certify that cable for dry use so we don't have data upon which to make a decision. If it's older NM with the silvered tar jacket it is certainly ruined. If it's modern NMD cable with a PVC jacket it would probably be fine assuming no breaks or rips in the jacket that would have allowed water into the cable. A detailed inspection would be a really good idea. If there is evidence of water having gotten through the outer jacket assume the whole length of cable is ruined - water wicks in and corrodes the metal from the inside out. Any devices that were submerged really must be replaced. Any cables where the cut ends were submerged must be replaced.

Be careful setting up and running your fans once the power comes back on. Use GFCI everywhere you can. Plenty of people have been shocked in receding floodwaters.

The crawlspace doesn't sound too bad once you get the mud mostly dried out. An electrician and a helper could probably get it done faster than you think. A 2-3' height isn't bad. A couple big tarps down there would be good enough to get the job done for a day.
 
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Old 05-01-19, 09:13 AM
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I might have been generous in some places, saying 2ft to 3 ft, but perhaps the re-wire could be done in a combination of crawlspace and main floor wiring.

It is definitely older wire. I suspect it would be original to 1978 or so. I noticed in a picture I have that it has a brown jacket with 12/2 NMD written on it. I am surprised that it would be 12 guage. I assumed 14 guage was inside wiring for the 15 amp circuits. Perhaps the guy who built it, over did it on the electrical or perhaps I am wrong on my codes. The wire I saw in my pictures, some was definitely just going to general outlets.

Would a "silver tar jacket" be the outside plastic or is that something would be behind my brown colored cover on the wire?
 
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Old 05-01-19, 09:47 AM
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I haven't seen brown jacket NM -- perhaps that's a Canadian brand I don't know. Older NM cable didn't have a plastic jacket, it was a tar impregnated fiber that had an overall silver gray color. At 1978 you're probably beyond that and into plastics, but you never know what somebody might have had on hand for building a cabin.
 
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Old 05-01-19, 10:52 AM
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Here is a picture of the wire I am talking about. Definitely Canadian. Those wires are moving along the main beam. It has become quite wonky over the years and the need to raise it up and fix it and the rotted sills was a job that was coming anyway. So doing it now because of the flood, is not really adding an additional cost from the flood, for that. Just wish I had done it before.

If they replace that main beam, which I think I would like, that wire has to come off anyway, but my urgent problem is getting power before that raising job could be done.
 
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Old 05-01-19, 11:40 AM
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That's definitely PVC plastic jacket on the cable. My personal opinion is that is it probably OK as long as the jacket was not cut or split to allow water in. Official position is that it would need to be replaced.

When the beam is replaced you can carefully pull those staples out, push the cables aside and re-staple them to the new beam once it's in place.
 
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Old 05-01-19, 12:31 PM
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The NMD cable is "Non-Metallic Dry" so it's not rated for wet conditions. But I agree it might be OK if the staples/clamps did not damage the plastic sheath and water never reached the ends of the cables.
If the wiring is redone under the cottage, you might consider using wiring methods and materials for wet (or even underground) conditions. And if there's an attic space perhaps distributing power from there would be an option that would eliminate the issue but it's more work.

​​​​​Something you could consider in the short term is to replace the breakers on the effected circuits with AFCI or even dual function AFCI/GFCI breakers. This would increase safety in case there's any damage that was missed, as well as in the future use of the cottage.
Those cables shown are 2-wire circuits on a single pole, so they would use single pole AFCI breakers which are more commonly available than 2-pole ones.
 
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Old 05-01-19, 01:10 PM
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OK. Thanks a lot for all the information. Your thoughts and suggestions are greatly appreciated.

My latest news is the water seems to be in a decline. Down 8 inches since my first post. My best guess is it did not make it into the main floor but she was darn close, so I will head down tomorrow to assess it better.

You see places in the world desperate for fresh water and it makes me think how much I would like to ship them some. If I could build a pipeline to California, the water would be on its way as we speak. I seem to have a little extra where I am.
 
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