Diary Of A Camper Conversion
It’s simultaneously a great thing, knowing in that moment you’ve learnt something. And a depressing thing knowing that it had to come from a mistake. A mistake that means you’ve got to rip out what you’ve already done and do it again.
I made the mistake of setting up my smart switches to switch the negative side of my circuits. I thought I was so smart avoiding a load of individual positive cables running up to the smart switches from all individual fuses. And I’d avoid loads of ground cables going back to the chassis by combining them locally at the switch. But I inadvertently created new problems and actually didn’t save myself the extra wiring I thought I had.
This setup means not only do i have to run my fused positive wire from the basin fuse board, to the appliance. But i have to run all my appliance negative cables back to my main fuseboard where I’ve located the smart switch. If i set up to switch the positive side, I could run one cable to the appliance and then locally, ground to the chassis. This means I have to run half as many cables.
I think i knew this when i was planning the system out. I’ve been putting in local grounds around the van, but then got carried away with the electrical install and went down a dead end road, so to speak.
The other and more worrying problem I’ve created (and the one that is the real electrical reason) is that if you switch the negative side, the appliance is always live with 12v. There is no way to remove the 12v when installing it working on the appliance. It’s actually a safety nightmare especially if there is a short to ground or fault in the appliance. For example of there was a short to ground on the electric water pump and it always had live 12v, then the electric pump would just start pumping. This pressure, sustained for a long time or when it’s cold enough to freeze pipes could cause a leak and then it would empty the entire water tank, even if the switch said the pump was off. It wasn’t off, it just wasn’t a functionally closed circuit, it was a fault closed circuit allowing it to run.
Not what I want happening…
So realisation is great. It’s going to save me from horrendous problems in future. But right now, I’m staring at additional work redoing what I thought I’d already done.
Such is life.