Van Gogh· Registered
Hey Neal, thanks for the props. The heat trace cable should be wired exactly the same way as the Facon heat pad -- negative to ground, positive to your self-installed nearby 12V fuse block.Really great posts I am learning a lot and applying to my van. I installed a Facon heat mat on a undermount water tank I use for a recirculating shower. I also picked up some self-regulating heat trace cable from OEM heaters very similar to ultraheat to protect the input and output water lines. I have a simple question, how did you connect the heat cable to the 12v power feed? The cable I have has two conducting copper cables (or they call bas bars) and a ground sleeve. The ground to negative is clear, the positive side is my question how to wire? Any help you can offer would be greatly appreciated.
Because I'm not entirely clearly which part of the power distribution process you're asking about, some of this may seem obvious, but I'll try to offer a brief overview if you don't have fuse blocks throughout the van. Generally speaking most RV/van builds have either a connection to the vehicle's 12V AGM batteries (and thereby the alternator when the vehicle is running) via CCP1 (always hot) or CCP2 (engine-on/accessory), or they have a house power system with lithium batteries, or both with a selector switch.
Then they have a positive line running to each fuse block throughout the van, then finally their 12V appliances have positive and negative wires running to the fuse block. Some fuse blocks have negative terminals too, so you just need to make one nearby ground to the fuse block, then wire a handful of devices to its negative terminals. That's the type I used, and a temporary install (first of four total) is briefly discussed in this post.
That fuse block distributes power from my CCP1 or house lithium power system, and it's where the positive and negative wires from my heat pad and my heat trace are ultimately connected. I actually ran one negative from the fuse block under the van and connected both the heat trace and heat pad negatives to that, then ran both positives inside the van and combined them before running them through the lighted switch on my water tank monitoring system, and finally wired that switch to the fuse block with a fuse large enough for both the pad and heat trace (generally add up the max amps and multiply by 1.5 or even 2).
If you're looking for connectors, I recommend getting a set like this (or buy 50 or 100 count of the Glarks brand on Amazon in the exact sizes you need) and a ratcheting heat shrink crimp tool. I had mixed luck with this one. Only one side crimps hard so the wire must always extend out the dot side and crimp tube should always be under the better crimping blank side. I had to adjust it a few times to get a tighter crimp, and I often use two or more passes, and/or flip the tool over and re-crimp depending on the situation. For the smallest pink heat shrink connectors that don't crimp well in any ratcheting tool, I use this little champ of a crimp tool that I bought for the molex connectors under the driver's seat for tapping the vehicle's IGN and RUN signals. It also has a spot for heat shrink, and it makes solid connections with the pink or even the blue ones, although it sometimes tears the shrink tube, which heating usually fixes or I just add a little electrical tape when it doesn't. Then you just need a heat gun, and this one is fantastic. I use it many times a day on all sorts of things, like getting labels off, stuck bolts, you name it.
For wiring, I tend to oversize (e.g. 12 AWG) because the copper content may be a bit low on it, but stranded tinned copper silicone jacketed wire available on Amazon from many resellers (e.g. Plusivo) is my go-to for most small DC appliances. It appears to all come from the same manufacturer in China. Silicone won't melt under the heat gun, and while it's a bit hard to stick tape to it and it does collect dust, the incredible flexibility and jacket strength are worth it. For the primary run to the fuse blocks (and their nearby ground) I use 6 AWG Ancor or other high quality marine wire with more copper content and fewer strands. Those wires rarely move, are firmly secured inside conduit, and need to conduct a lot of current. But for that you need a larger crimp tool. For signaling, 18 AWG tinned copper silicone from Plusivo on Amazon is fantastic. I've gone through many rolls of it. Will buy again.
I hope that helps.