What happens when it floods ??

[Chri5]

Just curious given the poor s.o.d.s who have houses under inches, feet or yards of water.

So if a part street was flooded, would the rest of the street have mains?

Does a head fuse drinking water just isolate the house or the street, given the system shock of dozens of houses getting wet at the same time?

What prevents sub and main stations from killing anyone in the water around them, if the station is still in service and the flood a flash?

Would there ever be a situation where an area flooded in a house had 'live' water?

If you have any facts, stories or points of note I'm sure given the current issues it would be very well received- cheers

 

[Steve]

water is not a very good conductor, and "live water" would not happen as the electric would flow to the earth that the water is sat on.

The DNO would not likely turn off supplies, but let them trip out instead.

 

[RF Lighting]

Contrary to popular beleif, water is not actually all that good a conductor.

This is the best picture I could find to demonstrate it, but supplies will often carry on running while submerged, providing there are not two shortable parts too close together.

I'm not sure about live water, but I suspect it is unlikely.

My local pubs cellar has been flooded a couple of times to above the cutout, and nothing has gone off

Notice the street lights are still lit despite being partially submerged.

 

[industryspark]

one of the factorys where i work was flooded in the recent drama....

one MEM switch fuse isolator (housing 300A fuses) which was powered from a busbar chamber was submerged well past the supply terminals on the bottom of the isolator.

no fuses or anything on our side blew which suprised me as the terminals are close-ish. as others have said, water isnt a brilliant conductor.

the only thing that did go was the red phase of the supply. as the supply transformer was on site i acompanied the YEDL guy who turned up to sort it out. He first replaced the fuse with a 'fusemate' device which is a carrier which instantly puts a fuse in when he tells it to by remote. the fuse held no problem, as he manually put a replacement one in there was an almighty bang and flash.

good job he had his full phase visor and gloves on!

he summised water had shorted the fuse to earth and the blast should have cleared/dry'd it. another fuse was put in and no problem.

not sure id fancy that job to be honest!

 

[just askin]

If water is such a poor conductor, then contrary to all the movies if someone throws the classic electric fire or hairdryer in the bath with you as long as you are not in direct contact with it (and assuming the bath is metal and is bonded) are we saying you won't be electrocuted?

Not that I am planning on experimenting I hasten to add

 

[Steve]

If water is such a poor conductor, then contrary to all the movies if someone throws the classic electric fire or hairdryer in the bath with you as long as you are not in direct contact with it (and assuming the bath is metal and is bonded) are we saying you won't be electrocuted?

Not that I am planning on experimenting I hasten to add

There was an episode of mythbusters where they tested this. IIRC, they had a 30mA RCD in the circuit and it didn't trip. Cool stuff.

 

[RF Lighting]

It depends. There are often impurities in the bath such as shampoo, bath salts, bits of skin etc which will substantially improve the conductance of water.

Having watched mythbusters on discovery channel, the fire in the bath scenario may work providing the circuit is not RCD protected.


Have you ever topped a car battery up? If so what did you top it up with?

 

[Adam_151]

It depends. There are often impurities in the bath such as shampoo, bath salts, bits of skin etc which will substantially improve the conductance of water.

Which in a lot of situations would be a good thing rather than a bad one

 

[FatGit]

Why pure or deionised water is a poor conductor, it can become a fair one if impurities such as salts are added. You may have seen the experiment at school in which a lamp was connected to a cell through a bucket of water. It fails to light untill common salt is added to the water, at which point it becomes a conductor and the lamp glows.