Electrics

Issues with original wiring

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Some of the wires in the roof had been damaged by water and/or heat.

More generally, it made to sense to upgrade the wiring to better quality while it was accessible. This old stuff was:

• only 1mm² copper wire, which has significant voltage drop over the 20m distance;
• solid core, which is susceptible to breaking;
• sheathed with an old plastic not up to modern standards of robustness.

Rewiring

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Here is where the wires leave the main house and enter a trench. There were 3 circuits — power, lighting, and hot water — each a pair of 1mm² wires, plus a single earth wire.

My amazing electrician managed to pull through 3 new circuits — power + lighting combined, hot water, and air conditioner — each three wires of 2.5mm², 2.5mm², and 4mm² respectively. This involved carefully taping the wires to avoid twisting inside the conduit… and a lot of dishwashing detergent as lubricant. It is important to use a fat wire for the air conditioner circuit to minimise voltage drop as this can damage the motor.

Wiring up the power and lighting was a first for me. My dad prepared a wiring plan:

It is mostly straightforward. There are 5 double power points, 5 lights with simple switches, and an exhaust fan. The only complication is the outdoor lighting (L1) because it is a two-way switch, controlling 3 lights.

The wires all run through the ceiling. And since the ceiling will be packed with insulation, I put the wires inside conduit: this gives them an airgap to prevent overheating (and is standard practice with hempcrete construction).

Remember that new beams sit across the front and back walls. I did not want to drill holes all the way down through those, so instead the wires just enter the wall through a hole in the edge of the ceiling. I guess it’s a feature now.

Nightmare switch

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The switch box by the door was the worst. It is a triple switch box: two switches control single lights, and the other is a two-way switch for the 3 outdoor lights. That’s a lot of wires.

My biggest was physically fitting the wires inside. I hadn’t planned ahead to have the wires easily push back into the wall cavity, and the 2.5mm² wires were quite thick and stiff. That meant I had to cut the wires short enough to fit the cover plate on, but not so short that I couldn’t secure them to their terminals.