strange question - flooding

gazdkw82 · Jun 16, 2016

We are having lots of flooding here in Leicester and it got me thinking. If your house was to flood to a serious height, lets say above 1 feet of water, the chances are the property's electrical supply cables will become submerged.

There is a good chance something is going to short at the supply end. My question is, what protection does the DNO have on the suppy entering the property? will it trip at the substation? how long would it take? is there a chance all that water could electrocute anybody in contact?

Bobster · Jun 16, 2016

gazdkw82 said:
We are having lots of flooding here in Leicester and it got me thinking. If your house was to flood to a serious height, lets say above 1 feet of water, the chances are the property's electrical supply cables will become submerged.

There is a good chance something is going to short at the supply end. My question is, what protection does the DNO have on the suppy entering the property? will it trip at the substation? how long would it take? is there a chance all that water could electrocute anybody in contact?

The DNO will have feeder pillars with fuses feeding say an individual street. The houses then have a fuse at the point of entry.

Questionable if the feeder fuse would blow, the fault wouldn't be a direct short and so the fault current may not be high enough. IIRC feeder pillar fuses are around 400A , or the ones I've seen are.

Regarding electrocution. Water isn't particularly conductive, (flood water will be more conductive than tap water as it will have more impurities) but yes there is a possibility of being electrocuted. The sphere of influence from the service head wouldn't be very big, you'd have to get fairly close.