Outdoor Light

heffo500

Hi

I have a street light at the end of a small car park and the SWA cable in the ground from the building to light has multiple joints buried underground over the run.

One of these has failed as I have a large drop in voltage on the run.

Would it be bad practice to run 20mm steel conduit on the tarmac fixed with saddles beside the boundary wall to the light as an alternative to digging up ground and replacing the SWA run?

I thought running SWA with cleats in the same manner might not be a good idea even though it would be so tight to the boundary wall that a car couldn't damage it.

I can't mount anything on the boundary wall due to the render being very unstable.

Thanks

heffo500

Any one able to help?

Willywally

Your using the conduit as mechanical protection for a cable that has mechanical protection built in to it. So in effect your doubling up on the protection side of things. Mounting it directly to the ground has more risks from accidental damage than mounting it six inches up the wall for example. Bear in mind the saddle will hold the conduit out an inch from the wall to the center of the conduit so you might be better off with a “P” clip if you want it dead tight to the wall. Another note to mention is that a 3 x 1.5 mm2 SWA will be tight in a 20mm conduit so it would only be suitable for straight runs. You might want to slide the lengths over the cable before you screw them together and fix it in place with clips or saddles.
Another option is to cut a track in the tarmac 2 inches out from the base of the wall and bury the SWA

heffo500

thanks for the response, I should have been clearer I intended to use 1.5mm twin and earth in the conduit instead of SWA.

Willywally

For t&e the condiut will have to be completely sealed from end to end. Meaning that no water can get in to the conduit. Unless you have all the gear ie: bending machine, stocks and dies etc and are competent doing conduit bends , off sets etc you might be aswell get a spark in

heffo500

I have all the stuff, Hilmor conduit bender and Rigid Stock and Dies and have done conduit work before so comfortable in my abilities.

My main concern was there an regs making this method illegal.