Flood damage immediate action procedures.

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Chippa Fate

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Hi I'm off to help out with the flooding recovery in Cumbria for a few days as a volunteer. Obviously most of the homes there have had their DB and ground floor systems under water for a while. I came across a suggestion for disaster recovery:-

For a DB with rewirable fuse, removal of flooded area ring main fuse, rinse with clean water to remove soil deposits from DB, etc visual inspection for impact damage and allow components to dry. After which partial system functionality can be restored pending return of mains supply.

Now obviously rcd's/mcb's etc are well goosed n full of silt but as a way to restore power to upstairs, I can't see a massive issues. Am i missing sommit?
 
I would quess the suppliers would want some paperwork beffore reinstating supply, we used to do smaller scale flood damage, and it wernt that easy to dry out, damp walls often gave low insulation resistance and sometimes small shocks when touched.
If power was on at the time, wet sockets etc often tracked across inside and even if dried were physically damaged internally.
Sometimes removal of clear circuits from the old db, total disconnection of the old db and putting in a temporary db to allow some power.
In extreme cases a temporay board and rcd protected sockets on a backboard just for worktools and humidifiers.
Well done for helping though.
 
If something is warm and filled with gas (assume that gas is air) and is submerged and cooled the air contracts and sucks in water to replace the space. To dry out it needs either a long time, weeks not days, or heating and placed in a very dry atmosphere possibly altering air pressure to try and suck/blow out the water. A mobile phone dropped in the loo for seconds can take a week to dry out in a rice pack.

So to regain power quickly only option is to renew many of the items. As already said power up while still damp and tracks are formed which are then nearly impossible to rectify. With distributor caps with old cars we often drilled holes through the track.

The only other method is to replace the water with something which will evaporate. Problem here is most items which evaporate also burn, so although washing the MCB in brandy will likely remove the water on power up it may well go bang. Switch cleaners are also a problem as often they will melt components may be devolve is a better word.

I am sure in lab conditions one could work out the safe time items need to dry for which will clearly vary from item to item after cleaning in industrial alcohol before reuse. But even then the alcohol will become more and more diluted when we used it to dry gas pipe lines we had to same it after cleaning to see how much water it had absorbed. Oil is no good as it will not mix with water.

Cleaning starters and alternators we used petrol, but a health and safety officer stopped us and insisted we use something less volatile so we moved to paraffin however it takes paraffin longer to evaporate so there was still paraffin deep in the windings when they were reassembled so first start was OK. However the heat of first start would evaporate the paraffin but now held in a closed starter motor. Next start and bang the whole starter exploded. Cure was to use special cleaning fluid.

So my method would be in light of my experience remove all sockets and MCB and RCD and bin them and then test each cable if clear then fit new sockets and MCB's and RCD's.

If the house is to be left until the summer before getting supply back then yes maybe you could clean out. But in the main time constraints means replace is the only safe way.
 
Chippa Fate said:
HFor a DB with rewirable fuse, removal of flooded area ring main fuse, rinse with clean water to remove soil deposits from DB,
Click to expand...
Even on old rewireable boards, the main switch will be full of dirt and rust (springs in the switch will be corroded), and flood water is filthy, containing substantial amounts of raw sewage etc.

If electrical equipment has been under water, it is scrap. Replacement is the only option.
 
Thanx for the reply, I had been told the "norm" is to pull suppliers fuse and disconnect meter, and notify supplier after the fact, but sorta hoped I could return some circuits with zero parts buy in, especially as I'm told most of the DB's are pre rcd. Apparently slit packed components are the main issue, shortly followed by earth loop faults due to corrosion.

Know what you mean about socket current tracking through damp walls had a reminder of that un not so long ago. But it's a good point to look out for, hopefully less of an issue on first floor and up. You never know I may get one or two homes safely back up if I hit lucky.

Allot of ppl on face book who were flooded are reporting rented/hotel accommodation shortage in the area so have to stay in their homes, so looks like I'm gona be giving lots o ppl some bad news about their electrical system over the next few days.
 
Your IR tester is your friend. You dont want to reconnect a circuit if it is going to fizz and pop inside some socket or JB.

I'm sure you know this but beware on entering a property if there is groundwater, or even soggy floors, if the power is still connected.

good luck, and well done for volunteering!
 
Yeh a under floor JB to upper floors could well be silted up n shorted out, good point, not gona find them easy. Looks like a new temp rcd DB and a couple of 2 gang sockets on a board is gona be the only real and quick solution. ty for reply.
 
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