Light switch circuit breaker - keep?

I'm installing an EZ - 21 circuit wire harness. Since the fuse block has a 30A fused circuit for the headlights and I'm using relays for the high and low beam lighting, should I keep the circuit breaker on the switch or remove? :? I'm thinking it won't hurt to leave the breaker, but want your opinions and/or reasoning.

Thanks,

 

if its a automatic reset breaker then i would defenitaly keep it, ever lost your head lights at the wrong time? i have... tractor trailer first trip out for me... skinny long bridge.... they will come back on after it cools and resets, may go back out but at least it gives you a chance, that first time it trips you arent expecting it,but if they come back on even for just a few seconds it will give you a chance to get it to a safe spot, i would make sure that the fuse is a greater amp than the breaker,that way the breaker will go first,if the fuse goes first they arent coming back on

 

Since you have installed relays, you have a different issue than Kaiser-willys is talking about. The latching coils of the relays take very small current (amps) to operate them, hence smaller fuse. The contacts carry the heavy load for the lights. If you continue to use headlight CB to operate relays it's just another thing that can go bad. (your option). If your headlight wires short to ground, it's going to toast your relay contacts unless your fused less than contact rating.

 

I'm not sure I follow the question but I would think that the power would go through the fuse panel to the switch then on to the primary (low current) side of the relay. Wouldn't this take very few amps? - like way less than the 30 amp fuse and probably way less than the CB in the switch? Just something to think about. I think your question was about having the fuse and circuit breaker in series but my question is the rating.

I assume you have protection on the secondary (high current) side of the relay.

Sorry if I'm off base, just throwing a few things out there.

 

may be way off base myself, but i like the idea of a automatic reset circut breaker on headlioghts especially,i would hate to think that when they went out thats it

 

Yeah, I've had the lights go out on two different rigs. Both times it was the switch.

So, remember to try and wiggle the switch or change from/to low/high beams if it ever happens.

 

Well, I sat down and did a little thinking about what kind of load I'd have on the circuit and have decided to remove the circuit breaker and go with just the 30A fuse that's standard for the headlight circuit.

This is my load on the headlight circuit:
2 ea. headlight switching relays @ 0.08A = 1.92W
2 ea. front parking lights @ 27W= 54W
2 ea. rear tail lights @ 27W = 54W
2 ea. trailer lights @ 27W = 54W
2 ea. trailer side marker lights @ 3.36W = 6.72W
2 ea. instrument lights @ 3.36W = 6.72W
2 ea. add-on dash lights @ 3.36W = 6.72W

Total wattage = 184.08W / 12V = 15.34A
30A fuse should do just fine!

Did I miss anything??

AKCJ - You're right about the original question - I asked if both fuse and circuit breaker were needed. I decided to have only the fuse to protect the circuit to make troubleshooting easier if a problem develops.
kaiser_willys - the circuit breaker may have an automatic reset feature, but if there is a short in the circuit, I'd rather have the fuse blow than a wire burned. I noticed on the existing wiring a couple of places that have overheated (melted plastic). I suspect a properly sized fuse would have prevented that.
Walt Couch - the headlights are protected by a fusible link on the switched circuit. My setup is very similar to Mike Boyink's wiring. I followed the "New System" approach shown on www.madelectrical.com website.

I appreciate the responses and suggestions from all of you.

 

I kept mine. Blowing a headlight bulb could cause a momentary short circuit, blowing your fuse where a CB would trip and reset. Same as a water crossing, and getting water/dirt in a socket. I agree with Kaiser Willys.

I think I'm missing something, what actually feeds your headlights?

I don't think I'd fuse a 15 amp load at 30A, maybe 20 or 25A. There is no start up current so it won't draw more than 15A. You'd be leaving yourself open to feeding a 16 or 18 guage wire up to 30A. Magic smoke time. I have lots of experience there after putting the 4.3 in the Jeepster last year, had an unused efi fuel pump wire touching the exhaust manifold, and believe it or not it would almost disintegrate the 16G feed. I was in the middle of nowhere and had to get out of there, so I jumpered in a piece of 10G and kept the sidecutters in my hand, I could reach the spliced in piece from the drivers seat. Not recommended. I actually wheeled it all day like that. Tore the whole harness apart to find the problem.

I'm not sure I was clear there, if you put a 30A fuse in for your signals, dash lights, relays, etc. what are you putting in on the high side of the headlights for a fuse?

 

I thought about a lower amp fuse as you suggest and will probably go with a 20A - good idea! It probably wouldn't be good to use a 20A fuse with a 30A circuit breaker, so the breaker is out.
I'm curious why the wire harness mfg uses 16 or 18 ga. wire on a 30A circuit?? :?

You ask "what feeds the headlights" - I have a terminal block fed from BAT + that is the source of power for the headlights. An 18 ga. fusible link connects to the wire feeding each high beam and low beam circuits that go to the # 30 post on each relay and will protect the rest of the harness in the event of a short.

 

Gotcha, I think I missed that part.