If the socket that connects an extension cord to an appliance's cord rests on the floor of a flooding-prone basement, does this entail any increased risks (e.g. electrocution risk, if the basement floods and the water level goes above the plug's contacts)? If so, what exactly are these increased risks?
Water gets you two ways.
First it greatly increases conductivity. If you walked by the extension cord on dry floor, obviously it does not shock you. But if it's underwater, and your ankle is underwater, wet skin conducts better than dry skin and obviously water with any mineralization in it conducts. So now electricity has a straight shot to you.
Second, often electricity will stun you without killing you. Water adds a huge complication. If you fall such that your nose is underwater, you drown. This is called "electrical drownings" and it is the bane of freshwater docksides.
It'll kill other people, too.
So someone hears the thump and goes down and sees you. They urgently run over to lift your face out of the water, and guess what! They get stunned too. Either they didn't think to go to the main breaker and cut the power, did not know you could pull a meter, or they could not access the main breaker without going through the water and getting zapped! This is why
- GFCI is required now in basements
- "meter-mains" (outdoor main disconnect/breaker) are required now
So the 2nd rescuer comes up and sees 2 people face down. Will that person realize what is happening or will we have a third casualty?
The record for "consecutive rescuers" taken out is 3 + the original victim.
OK, in the past here I've been told that I'm not emphatic enough...just the nice guy in me. But on this question, I'm going to go to extremes: ARE YOU NUTS! That is EXTREMELY DANGEROUS. You may as well get into a bath tub with a plugged in toaster (think the scene in Ground Hogs Day with Bill Murray. )
A plug/socket immersed in water will WILL WILL energize the entire floor area. Electricity doesn't care where it goes, if someone walks in the flooded area, and the path of least resistance is up one leg and down the other, that's really really bad, to the point of muscle contractions so strong you can't move your legs anymore. So you'll be standing in the flooded basement, unable to move getting the begesus zapped out of you. And God forbid they'd touch a grounded appliance or device which would provide a direct path thru their body from hot to ground. Death would be likely.
Even if no one was affected, think about the corrosion the water would cause on the plug/socket. Eventually it would corrode enough to cause a poor connection, which could lead to lower voltages to the appliance, which can damage them, or WORSE: Poor connections tend to run hot, creating a fire hazard.
At an absolute minimum get that extension cord suspended along a ceiling or high up a wall. A much better solution would be to do the needed wiring so you don't need an extension cord.
From least serious to more so, in my experience, roughly comingling financial and personal effects:
- Nuisance GFCI outlet trips
- Nuisance breaker trips
- Appliance shutdown due to nuisance trips
- Scary pops and sparks
- Damage to appliances, cords, etc.
- Zingy tingling sensations
- Damage to house wiring and equipment
- Uncomfortable or painful muscle spasms
- Damage to home due to fire
- Unconsciousness and related fall trauma*
- Death and related fall trauma**
* No personal experience, but I saw it on an episode of House.
** No personal experience, but it's pretty gross from what I remember of that one scene in Tango & Cash.
It definitely increases the risk. Which is why code now requires GFCI for receptacles in an unfinished basement. (I am no code expert, but my hunch is that in a finished basement the risk of water on the floor is significantly lower simply because people try to deal with potential water problems before finishing a basement so that carpet, etc. doesn't get ruined.)
This is also one of the reasons (additionally: trip hazards, undersized extension cords, probably other reasons) why there are rules about maximum distances between receptacles, though the rules do vary depending on the type of room. If there are enough receptacles in the right places, you will not be as likely to use extension cords for unattended use of appliances.