Wiring Question

I worked on rewiring my 1952 Chevy this weekend. Engine compartment done, dash 95% done. Still need dome light and rear harness. But while pulling ALL the old wire out, I noticed that there isn't one fuse in the entire car. Normal? It already has be switched over to 12v, so I am just installing new wires, and making them look pretty.

I am a motorcycle guy and have built a few choppers. So when I do my wiring on a bike, it's a circuit breaker between the key and the battery. But nothing else. Can I get away with that on a BASIC wiring job on a car? Headlights, tail lights, heater fan, wiper motor, dash/interior lights, aftermarket blinker switch on steering column, horn, radio (future addition). Or do I need to have a fuse block powered by the ACC on Key to all of these?

Thanks.

Also, I have done all of this from scratch, no "harness". Ran all my own wires, installed terminals and heatshrink.

Right now, I have dash/interior lights and running lights on headlight switch. Coil, heater fan, wiper motor, horn, blinker switch being powered from ACC on Key. No fuses besides 40amp circuit breaker between Batt and Key.

 

I'd run a fuse a box, you don't want to stall out on the highway cause your heater motor shorted out.

 

I would recommend a fuse box of some sort. 40amps is a lot too. Should something happen to one of your components you would almost have to short it to ground to get your CB to open. I would think your car would burn down before that would happen.

 

Looks like I am running a fuse block now. Battery power into Key, ACC to fuse block? And then everything off of there?

 

originally the light switch has breakers/fuses, if it has been replaced with an aftermarket universal switch they might have been removed. The radio/heater should have inline fuses.

I'm chicken, I put a fusible link in the main power feed wire where it connects to the starter or battery

 

at swap meets you can usually find fuse boxes cheap

 

Gonna use the block you can get from the local autoparts store. They have the tabs so you can mount a few together.

 

I fuse every + wire. No two wires off one fuse. That way you will know what one is causing you a problem and you only have to wring out one wire.

 

I would take squirrels advice on the fusible link.

You won't be able to turn anything on without the key being on first your way. You will need battery power to light the rail in your fuse box for your lights, dome light, etc.

 

You really don't want to run your main electrical loads thru the key switch. The ignition and start function, maybe a low amp draw radio would be enough. The rest of the loads can be put through relays that are triggered by the ign switch. The relays draw very little current and can carry pretty heavy amp loads. There capacity will be marked on them. Still should have fuses between the relays and the loads however.
An salvage yard fuse box or an aftermarket unit like Ron Francis supplies will provide all that already ***embled. You could just tie in your new wiring and have a safe, reliable system.

Ray

 

That's how I, one circuit at a time, wire all of mine. I ditched the voltage regulator circuits and opted for one-wire alternator. Main wire from starter post through 60 amp slowblow up to Ammeter(internal shunt 60 amp capacity). Off the other terminal of the Ammeter to the 'accessory' terminal on the ignition switch, then through inline fuse to the unit. I put the inline fuse where it's easily accessed. Lights, horn, etc(anything I want hot even when ignition is off), direct from ammeter terminal thru inline fuse to unit. Simple, Safe, reliable, idiot proof.

 

That brings up another question. Ammeter? Wire it up before key? After Key, before fuse box?

 

Fusible links are where it's at. I do one in the charging line from the alternator. One in the main harness feed.

When making my own harness not from a kit, I use those 4 place fuse holders you can get from any autoparts store.

One for constant feed circuits. Radio memory, clock, heater fan relay feed (30 amps, sometimes this is a circuit breaker from one of the kit manufacuters) Headlights, brake lights, Horn.

One for accessories.Radio and whatever else I want on when the key is in the acc position. My personal preferance is that I don't like my gauges and heater, wipers and everything else on when I'm sitting somewhere and just want to listen to the radio.

In the on position I use relays and a fuse block.
My reasoning is that the aftermarket simple ignition switch with a key only has three positions and start. acc, off, on. These switches in each position only have one set of contacts. These contacts were never intended to carry much current, most are 30 amp max switches. You can easily see the potential for failure if you have more than a few on at a time. So I use the switch as just that, a switch to trigger relays to carry the current instead.

A relay (or two, depending on the load) for ignition fed accessories. Wipers, heater control(usually this is a purple wire from one of the kit manufactures), charging system field, electric choke,electric gauges etc.. These also go through the accessories fuse block(s) after the relay before the accessory itself. This is it's own mess.

Another separate relay for the ignition system itself. In order to eliminate feed back.

If I have an electric fuel pump it gets it's own relay. Same for the cooling fan.

Over engineering makes sense to me.

Brant