Can you recommend ducting?

[ziggs21]

We need to run the mains cable under a concrete floor and suspended wooden floor. The power supplier has advised that we should put the ducting in ready for them to put the cables through. Rather than dig up the concrete we may put in a suspended floor as the floor level in that part of the house is below the level of the rest of the house anyway

Do we need any special sort of ducting to protect the cables from enthusiastic DIYing in the future? Wouldn't like to cut through a mains cable!

What would you recommend/use in these circumstances?

 

[Steve]

It is highly unusual for the suppliers to run their mains cables inside houses. Normally, they fit their stuff on an outside wall, keeping the unprotected cable on your premises to a minimum - their side is on 5000 amp fuses and the like at the local substation. Where it enters your home it is fused down to 100 amps or less, this is where your electrician takes over.

Are you sure they didnt think you meant an outside concrete floor?

 

[ricicle]

5000 Amp Crafty ????

 

[JohnD]

It is highly unusual for the suppliers to run their mains cables inside houses...

Might be unusual in Yorkshire! Quite common here. Mine runs in a plastic duct under the garage floor with the meter at the other end.

 

[Steve]

Maybe it is common in some areas, but i've never seen this.

I was guessing at the fuse ratings at the substation.

I'll go and hide in my corner now.

 

[Adam_151]

400A per phase would be a more normal figure, would you believe it, if you assume 1kw-2kw average load for a house, then you can have quite a few of them, the diversity works in practice becuase the thermal capacity of all that metal and oil allow the transformers to take quite big overloads (and I expect the fuses will have been chosen to have a fusing factor to match with this)

Still, if you drive a screw into a supply cable, expect the end of the screw to to disappear before the fuse blows...

 

[JohnD]

My uncle (ex-SWEB) told me that on one occasion he went to a transformer feeding a factory near Bristol, and found the oil had all boiled out from overheating due to overload. this was during wartime, so he and his buddy tipped a barrel of fresh transformer oil into the hatch and ran behind the nearest wall in case it blew up (it didn't).

 

[ziggs21]

Hi folks,

Definitely needs to be run inside the house. We want to put the consumer unit under the stairs. The engineer that visited said that we would also need to move the meter and that we should put the ducting in place under the floors ready for them to run their cables through. They will put a junction box on the outside of our house because next door looks like it might fall down any minute so it's unsafe to continue with what we have which is the supply cable attached to next door's render.

We will need an electrician on site to connect the new consumer unit to the meter once moved, otherwise everything else will be ScottishPower owned and maintained.

We shouldn't have anything left at the location where the meter and fuse boxes currently are as this will eventually become a part of the kitchen...not safe to have the meter there I would imagine.

So is plastic duct ok? Would we need to put a sheet of metal over the top to prevent damage? What diameter?