Cabling through external walls - above DPC or below?

[DIYLancer]

I am installing a 30 Amp power cable to provide electrical feed for my workshop and need to pass the armoured 3-core power cable through an external wall into the house. Should I go below the DPC or above it? In either case, what is the best way of sealing around the cable? Silicon? I know the drilling should run downhill towards the outside, but by how much?

To thwart obvious suggestions about getting a qualified electrician in, I have - I am simply installing the cable!

Grateful for good advice please. Thanks.

DIYL

 

[PrenticeBoyofDerry]

Although you would require an electrician to certify new circuit and commission using schedules of inspection and tests.
It would be wise to have one on board prior to you starting the work, as it is not quite as simple as just installing a cable. There are factors in to the design of the circuit to be taken in to consideration such as:
*Load demand
*The route of cable and method of installation
*Distance of cable for voltage drop.

This is required so you can safely install the correctly rated cable for desired load over the distance the cable is run and that the cable is securely and safely fitted in compliance to BS7671.

Other than that, I would install above DPC, a slight outward slope of 10mm over 300mm will be adequate to prevent water tracking back internally. If the cable is to go upwards (external wall), then forming a drip loop would also help prevent water ingress, Sealing the hole with a silicon suitable for external conditions will also be recommended.

 

[SimonH2]

I'd suggest the biggest factor is where the cable is going.

If it's buried outside, and is to go under the floor inside, then the natural place is below ground level. If it's to end up going up the wall (eg to reach the CU) inside then it makes sense to drill the hole at quite a steep angle so as to reduce the bend required (SWA is not very flexible).

So some more detail would elicit better answers for your particular situation.