Power supply questions

[steph57]

Hello, to cut a long story short, we need to sort out the power supply to our house and put it onto a proper basis. We have permission, wayleaves etc for a trench to run a Western Power Cable onto our property. The cable line passes by the site of the new detached garage we are having built and then has to somehow worm its way across existing waste and water pipe runs and into the house. We have had various people commenting on specific aspects of this but it is hard to get an overall view. My questions are;

1. What are the options/best practice for running a power cable directly across the existing drainage and water pipes serving the property. Do we need to excavate around the pipes and put the cable underneath?

2.Is there any merit or advantage in terminating the western Power cable at a meter box set in to the wall of the new garage with an isolation switch-fuse and then running one feed for the garage electrics and and a second feed for the house consumer unit? So that the cable running across the pipes around our house is our cable rather than the Western Power feed cable? At a push this could possibly go overhead between the new garage and the house although it would be a a long run of cable just to go up and down. The direct route to the consumer unit would be underground but as i say this means going across drain and pipe runs.

What I am looking for is some guidance on who to speak to and what questions to ask in order to move this project along.

Thanks Steve

 

[mfarrow]

Whether the cable goes above/below the services is dependant on the minimum depth WPD have asked for. This is typically 500-600 mm. There will be instruction as to what duct they expect also, and they may be able to supply this.

Cabling to your own box and out in armoured cables to house/garage will be fine but you'll still have to maintain the minimum depth of 500 mm to comply with IET best practice guides, which will help assure compliance with wiring regulations.

 

[bernardgreen]

Use a duct and go UNDER the water and soil pipes by 100mm. That way you can if necessary work in relatively safe conditions on the pipes without having to have the power disconnected. But put "electric cable" marker tape between duct and pipes.

Having the meter and wired fuses remote from the house is OK. Use wired fuses as they are not as fast acting as MCB so the MCB in the house will trip before the wire fuse ( that is protecting the cable ) blows

 

[westie101]

Cable depth for a DNO cable should be a minimum of .45m in that location, if it is single phase some 32mm duct would be a good idea as iot allows the trench to be backfilled before cable installation. As others say marker tape over the duct as well

 

[bernardgreen]

When installing the duct take photos with clear indication of the depth before back filling the trench so you can prove the depth was compliant with the DNO's requirement.