DIY - Build and install a Bussmann RTMR Fuse/Relay Block

I think custom connector kits. com has those mounting plugs for various connectors.

 

Trying to make this panel as small of a footprint as possible. Anyone think this is too sharp of a bend for the main power feed? It doesn’t seem to be terribly kinked but then again I don’t usually deal with such short wire runs.

 

@kmorgan3 how about a pass through terminal and some super short jumpers?

 

I thought about that but decided against it as it would just require more holes in the panel that might not be necessary. The bend I have isn’t severe enough to damage any of the strands (I don’t think), but I’m unsure whether it will introduce enough resistance to be considered a hazard.

 

I’ll try to read up on resistance w copper stranded cable bends. Can you measure it with an Ohmmeter?

 

I think first order principles say that unless you’re changing the effective surface area of the wire, then conductivity doesn’t change. It’s possible that stressing a wire severely might cause some sort of surface change? Second order effects such as inductive resistance..... I couldn’t say without pulling out some of my really old school material.

 

Found some online stuff suggesting a radius of 6-10 times the wire diameter.... but that seems to be for high voltage stuff... >5kV.

 

Yes exactly — reducing surface area increases resistance through a conductor (assuming all other values remain constant). Bending can cause a reduction in surface area but just wasn’t sure how far we can go before we choke it (esp. larger gauge wire handling higher amperage — although our voltage is super low at 12). Multimeter test came back with nominal resistance (0.2 Ohm) so I guess that’s good, but would the resistance scale with load? Physics was a long time ago.

 

Yeah gut says low Voltage and large gauge means no problems at all.

 

I don’t believe resistance varies with voltage or amperage. Induction, though, may well vary.

 

Sounds like TW (and your meter) say you’re good to go.

 

The bend is ok but I’d make a semicircular notch to give it clearance. That’s one wire you can’t allow to rub since the panel is grounded to the chassis.

 

Awesome; I’ll make a little notch there. It’s not touching but I’m sure it will when I hit washboards.

 

Make it like an inch deep and you can turn that kink into a smooth curl and still have some clearance.

 

I would drill in a 1/2" hole - put on a thick 1/2" rubber stop-tube (looks like a piece of rubber pipe with a hard plastic washer on the end) around the middle and pass it through the hole and then re-connect it.

 

What about a 1/2” rubber grommet?

 

That’s what I used when further from the edge but you could do that just as well. Go much beyond the edge and the cable will end up with kinks top and bottom instead of just the one. Which is why I recommend a short notch. You could make the notch fit the grommet though. Once connected it shouldn’t be able to slide out.

 

I would place a piece of rubber tubing on that edge.

 

Here’s a link to the Digikey page for the JAE connectors, the 5-pin green ones commonly used with aftermarket switches. lots more choices than just 5-pin and cheaper than molex.
https://www.digikey.com/en/products...OwAMIAugL54wAsUoyk62ehkJYpAZgCcAVhB5+w8rTqygA

 

Maybe this could be pinned to the install/build page(s) to help others in the future?