XJlimitedx99

So I'm in the process of wiring roof lights and I ran into a snag. I am running five 55w lights, which would equal about 20 amps (275/14). My plan was to reuse my old 8awg subwoofer wire which would be plenty to handle that current but I'm curious about how to safely go about connecting it to the relay. When I ordered the relay I bought one of those fancy connecters that plug into it to try to keep everything clean but the connector only has 18awg wire!? I know that there's no way it's safe to splice the 8awg to the 18awg, plus the inline fuse in the 8awg wire is wayyy oversized for 18awg wire. So, do I ditch the relay plug and just use spade terminals? Even with that how would I get a spade terminal to fit the 8awg wire?



I know the 8awg is probably overkill, but I don't know if I feel comfortable using 18awg to power 5 lights.

salad

Yeah 8 is huge lol. Voltage drop is a function of distance and conductor size. If you use 12 AWG onto a crimp-on spade connector and transitioned to 10 AWG or 2x 12 AWG after just a couple of inches you'll be fine.

I gotta ask, what kind of relay only has 18 AWG on the load side? I bought some 30/40A relays that came with sockets with 12 AWG tails

5-90

8AWG is overkill - I'd probably use 12AWG.

As far as wiring up the relays? You may use 1/4" spade-style quick-disconnects (select for gage, I think the ones for 12AWG will have yellow butt sleeves,) or you can check my site - I have unassembled relay block kits for DIN relays that will accept wire up to 12AWG (loose terminals - you'd crimp them yourself, and insert them into the block. That way, no splicing.)

Oh - when you're figuring current requirement for automotive wiring, you can either add a 10% safety factor to what you get [(275/14)x1.10] or use the nominal 12VDC (275/12) and, since actual operating voltage tends to run 13.2-14.0VDC, you'll have an inbuilt safety factor without even trying. I tend to prefer the latter method - it's fewer steps (so you don't forget one,) and the number you get is more useful, from a safety standpoint.

XJlimitedx99

Thanks for the help guys, I bought the relay and connectors online, I don't remember where. I ended up ditching the connectors because they were junk, and apparently the relays are too! After wiring everything up yesterday I flip the switch for the first time annddddd nothing. Had power going in and power on the trigger wire but nothing coming out.

XJlimitedx99

Well turns out it wasn't the relay, dummy here just had two pins in the wrong place!

5-90

Lemme guess - Song Chang Chinese crap?

Bosch, Omron, or something similar - if you're going to do it, do it right. I know Chinese people who don't trust Chinese parts, that has got to tell you something...

5-90

Oh. Still, if they're Song Chang parts, plan on sourcing replacements soonest. Worst relays I've ever seen for service...