Hypothetical

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Shaneyj

Shaneyj

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Location
Katy, Texas
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Project Engineer
Doing flood clean up here in Houston and an interesting question comes up.
What are the physics behind a 120v outlet being submerged in water... Assume a living room with several outlets submerged. Circuit stays energized.
Is there a standard voltage gradient for water? Is voltage 120v next to outlet, and dissipates as distance from outlet increases?
Think standing water, not clean(ish) rain water, but whatever is floating from what's picked up from streets, lawns, yards... Trash, sewage etc. Fairly decent conductor.
Thanks for the replies.

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Shaneyj said:
Doing flood clean up here in Houston and an interesting question comes up.
What are the physics behind a 120v outlet being submerged in water... Assume a living room with several outlets submerged. Circuit stays energized.
Is there a standard voltage gradient for water? Is voltage 120v next to outlet, and dissipates as distance from outlet increases?
Think standing water, not clean(ish) rain water, but whatever is floating from what's picked up from streets, lawns, yards... Trash, sewage etc. Fairly decent conductor.
Thanks for the replies.

Sent from my HTC6545LVW using Tapatalk
Click to expand...

Voltage gradient changes quite a bit for fresh vs saltwater. Dirty water, no telling where that falls. If possible, de-energize the house before entering. I do not know the proper protocol or safety measure one should take in entering a powered dwelling that's still underwater. istm to be premature at that point. If I had to do it, and I'm not recommending this at all, but if it were me, I'd have a set of rubber hipwaders on, rubber gloves, make my way to the panel and kill power. If the water around the house has receded, I'd pump out a basement with a portable gas powered pump before entering it.
 
A few ideas:

1) Something has sealed the outlets to prevent liquid from penetrating boxes.
Perhaps painted over outlets with attached cord & plugs, and/or Tamper-Resistant inserts?

2) HACR breaker(s) can hold inrush & sustained current, if below trip-curve limits.
Perhaps flood debris is not a reliable conductor above several amps?

3) Arcing not detected.
Perhaps arcing wiring burned up inside wall/boxes, before extinguished by liquid?
 
ramsy said:
A few ideas:

1) Something has sealed the outlets to prevent liquid from penetrating boxes.
Perhaps painted over outlets with attached cord & plugs, and/or Tamper-Resistant inserts?No. None of these keep water out of the junction box

2) HACR breaker(s) can hold inrush & sustained current, if below trip-curve limits.
Perhaps flood debris is not a reliable conductor above several amps?Maybe, sort of

3) Arcing not detected.
Perhaps arcing wiring burned up inside wall/boxes, before extinguished by liquid?No
Click to expand...

Fresh water, even when it's dirty, is not all that conductive.
 
JFletcher said:
Voltage gradient changes quite a bit for fresh vs saltwater. Dirty water, no telling where that falls. If possible, de-energize the house before entering. I do not know the proper protocol or safety measure one should take in entering a powered dwelling that's still underwater. istm to be premature at that point. If I had to do it, and I'm not recommending this at all, but if it were me, I'd have a set of rubber hipwaders on, rubber gloves, make my way to the panel and kill power. If the water around the house has receded, I'd pump out a basement with a portable gas powered pump before entering it.
Click to expand...
Thank you... This was more to satisfy curiosity... I have read a fair bit in the last week regarding electrical safety with flood damage.
To be clear, I've had the utility shut off service and will not call for a reconnect until I verify all circuits.
My plan was to use a megger to determine integrity of each circuit.

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Shaneyj said:
Is there a standard voltage gradient for water?
Click to expand...
for pure water, yes. anything else no. all depends how ionic the water is. salt water is a good carrier of e-trons, std tap water not too much.

a stagnate pool of dirty water may have some gradient, then when you move the water that gradient can change to better or worse, etc.

since garbage contains lots of chemicals, those chemicals leach out into the water and can make water very ionic, all depends on how much garbage, type, stagnate, etc etc.

however, from a shock perspective, i would rather be in salty/dirty water than clean water if electric was under the water.

replace replace replace, and dont be in the water with the juice on, that sour can bite.
 
JFletcher said:
Voltage gradient changes quite a bit for fresh vs saltwater. Dirty water, no telling where that falls. If possible, de-energize the house before entering. I do not know the proper protocol or safety measure one should take in entering a powered dwelling that's still underwater. istm to be premature at that point. If I had to do it, and I'm not recommending this at all, but if it were me, I'd have a set of rubber hipwaders on, rubber gloves, make my way to the panel and kill power. If the water around the house has receded, I'd pump out a basement with a portable gas powered pump before entering it.
Click to expand...

Residential basements are rare to nonexistent in Houston.
 
Shaneyj said:
Doing flood clean up here in Houston and an interesting question comes up.
What are the physics behind a 120v outlet being submerged in water... Assume a living room with several outlets submerged. Circuit stays energized.
Click to expand...
Jraef has kindly provided a link to procedures for refurbishing/replacing equipment that has been water damaged. None of the procedures are carried out live.

Personally, I wouldn't consider entering a building with live, submersed electrical equipment. I think many others wouldn't either so, to that extent it is a hypothetical and the question of how well the type of water conducts is an irrelevance. IMO.
 
Besoeker said:
Jraef has kindly provided a link to procedures for refurbishing/replacing equipment that has been water damaged. None of the procedures are carried out live.

Personally, I wouldn't consider entering a building with live, submersed electrical equipment. I think many others wouldn't either so, to that extent it is a hypothetical and the question of how well the type of water conducts is an irrelevance. IMO.
Click to expand...
The physics of the scenario is what intrigued me. If you read my other posts you would see that safety is my real world concern.
Nowhere in my post did I suggest I was gathering information in order to attempt the scenario you described.

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Shaneyj said:
The physics of the scenario is what intrigued me. If you read my other posts you would see that safety is my real world concern.
Nowhere in my post did I suggest I was gathering information in order to attempt the scenario you described.
Click to expand...
I described it as hypothetical. Which is agreeing with your take.
 
I don't think OP was necessarily asking how to enter the flooded house while circuits are energized, I think he was asking what goes on in submerged energized wiring.
 
kwired said:
just a general question of what happens when energized 120 volt item is submerged in water.
Click to expand...
Then he have simply asked that general question. Nothing hypothetical about it.

Somewhat related, I've been to quite a few different countries and have seen practices that many would have raised eyebrows at.
One was motor maintenance in the Far East. The motors were dismantled, the end bells and rotor removed. The stator was flushed out with water and then left to dry in the baking hot sun. Means and resources. So getting something soaked isn't the end of the world Operating it under such conditions is another matter.
 
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