Cross-section of a three-phase electricity cable.
At the end of last year we were down on site supervising the installation of our electricity mains cable. The logistics required careful planning as we had to coordinate between Wiston Lodge, the man digging the trench for us, and ScottishPower. The electricity cable has to run from the distribution point behind the Lodge, across the front of the Lodge and its parking area, along a track, down the side of a ravine, under a burn, and up the other side to our plot. From the perspective of Wiston Lodge, the key things was to schedule this at a time when they weren’t busy with lots of groups and guests given that an open trench was going to cut across the front.
Part of a long trench
In the end it all went fairly smoothly. Our contractor, S, arrived on Tuesday 27 November and dug the trench from near the distribution point to the end of the track at the top of the ravine. On Wednesday he dug the rest of the trench, including a 2 metre square hole near the plot. This is for the jointers to join the three-phase (used for most of the length to maintain the voltage) and single-phase (to connect to the house) cables. The one issue was that the ducting placed in the trench under the burn filled with water, as did the trench on either side of the burn some way up. S managed to drain the trench and push much of the water out, but the short days the failing light meant he had to return the following morning to finish the job.
On Thursday, bright and cold again, S arrived early and cleared the water out from the ducting under the burn. ScottishPower then arrived to lay the cables. It was quite an operation, but after some hesitation on their part regarding the distance of the end of our trench from the electricity pole, everything proceeded smoothly. (They wanted it 6 metres away, but the gap was 11 metres, based on my conversation with the ScottishPower woman handling the administration of our connection. The first of several experiences with big utilities where the office and the people on the ground are working to different specifications!)
By the evening, the cables were all laid. S returned the next day and backfilled everything except the jointing box. The jointers came along the following week, connected the three-phase and single-phase cables, and then connected the three-phase at the other end to the live mains at the distribution point. The last of the backfilling was completed and there we were – electricity to our plot. What we didn’t have was a meter. That was installed without fuss in February, and we will soon have an electrician hook up some sockets and run power to the site cabin.