This is a story of how I ignored some basic good practices for electrical wiring and could have burned down my coach. The takeaways are 1) regularly inspect your transfer switch and visually ensure your wiring is good, 2) don’t take shortcuts as “temporary” ‘git ‘er done’ fixes have a tendency to become permanent and can become a liability later. The issue was entirely my fault due to the poor execution of the physical wiring job.
So two Christmases ago I decided to install a Progressive 30amp surge. (I had contacted Progressive earlier to ensure it would be Ok to wire it in my transfer switch after the transfer point; due to difficulties of the wiring layout of my coach, any other config would have been a major rewiring headache. They said their recommended install was to put it only inline with shore power before the actual transfer to protect the switch itself, but it was OK to have it after the gennie too. They just felt it was redundant there as the gennie should have its own voltage protection. This is an entirely separate discussion from the meltdown- I only mention it if anyone is curious about how I wired this in the transfer switch.)
It was a quiet day in a quiet campground where I had the entire section to myself. I decided to take up the job, as I thought I had everything I needed. Turns out I didn’t have a new twist nut rated high enough for the switch, and I also brought the wrong size romex knockout clamp. Since the stores were closed I just reused the old twist nut and went without the clamp for the time being, planning on returning later to fix. I used Wago clamps for all the solid copper to solid copper connections, but the main pigtail wire on the transfer switch was a twisted wire that I was marrying to a solid copper- so a nut was needed. I never did go back and clean up either of these workarounds. So what happened? I was exercising my gennie last weekend when all AC power unexpectedly went out- gennie was still happily plugging along. I checked the outlets and no voltage, gfci wasn’t tripped, so I went down to the electrical bay. Progressive unit was dark. I opened the transfer switch cover, jostling the romex cable and the progressive came to life, along with a sparking connection on the power line in the transfer switch. The loose connection had pushed through some serious amps and completely melted the wiring nut, and had begun melting the side of the transfer switch box. Progressive now showed a PE-4 code (previous error low voltage). I shut everything down and fixed it, like I should have the first time.
Lessons reinforced:
1) don’t reuse twist nuts- particularly the large cheap ones ones you’ll find in your coach.
2) Tape your twist nuts with a crisscross to the wires. I actually did that here, but it didn’t hold because I didn’t .....
3) properly anchor wires in and out of connection boxes. This protects connections from working loose.
A perfect storm of sloppy work, although it could have ended much worse. Maybe someone can learn from my poor decisions; I know I have!
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