In-line fuse for Cigarette Lighter

[samkost]

For a back up safety measure, I want to add an inline fuse for the always hot cigarette lighter connection to the fuse box (red wire).
After reviewing past forum posts, some said 20A to 30A.

Would a 30A size inline fuse be correct for the after market cig lighter harness?


Thanks everyone,
Sam

[HotWheelsFan]

Fuse needs to be rated for the wiring before the fuse...

The weakest link before the fuse could be connectors as well as the wiring, thus using a higher amp fuse if the wiring can't handle the load would heat the weak point until burning or blowing the fuse.

You could use the rating GM allows the lighter spec to supply, if the wiring is good with no poor connections or wire a new power supply with the rating you want.

Bob

I looked at my wiring documents and it appears the wiring to the cig lighter could be fused from the fuse block from the hazard fuse.

Also, fuses are best placed closest to the power source for most situations.

[PbFut]

You are primarily attempting to avoid a catastrophic issue with a short and not likely worried about over taxing the original wire give those lighters pulled a fair amount of current. I would experiment a little. Don't go very high unless the devices your are attempting to power are pretty heavy. Start with a 15. If you are using the lighter, then move up some. Fuses don't limit power, they simply blow. Work up to a fuse that meets your needs. I bet the lighter will pull more amps than any device you intend to use. Hence the logic that most devices can run off a lighter plug.

[samkost]

Thanks PbFut and HotWheelsFan, great advice!
I don’t smoke and I will probably won’t need to use the lighter if ever.
Just wanted a functional accessory and a fail safe connection.

So the inline fuse closest to the cig terminal on the fuse box will weaken the connection wire load on I believe to be a 12 gauge wire for these repo lighter wire harnesses?
I can jump off the hazard fuse? How should this be done and tied into that panel circuit?
If I decide to use the inline fuse, start with a 15A and see what happens after testing the lighter?
I appreciate your replies and any more advice.

Thanks all,
Sam

[dmjlambert]

If you're not using the GL BOX & SPOT LP terminal of the fuse box, you can simply plug the cig lighter wire in there, and it'll be fused.

[samkost]

dmjlambert,
I installed a glove box light/harness already.
I assume adding both accessories to that 15A Glove Box/Spot LP circuit wouldn’t be feasible/safe?
Thanks Sam

[dmjlambert]

I think it would be just fine.

[Accelo]

The amperage of a car cigarette lighter can vary depending on the make and model of the car. However, most car cigarette lighters are designed for a maximum of 10 amps.
Many Fords use a 15A fuse and in general GM uses a 10A, when they are fused.

[samkost]

Thanks Accelo,
A wealth of great info from all the replies.
I still find it odd that the original cigarette terminal location at the fuse panel is unfused on our trucks and that it is grounded to the dash.
One thing emphasized from this forum is you can never have enough grounds.
I have read many posts from years past about many different electrical configurations.
I just learned about this fuse tab for an extra fused terminal connection.
Still learning to better understand the amperage’s and wire gauges of accessories on these C10’s.
Thanks again everyone.
Sam

[Accelo]

Many of the 60's Chevrolet's didn't have a fused glove box lamps either.
Guess it was considered unnecessary by GM. If GM could save a nickel they did.
Cheers

[dmjlambert]

In theory most of the wire in the truck is protected from burning up due to a short. There is the circuit breaker built into the headlight switch for the headlight wires, fuses for most of the wires that are smaller than 12 gauge, and the wires that are unfused are mostly 12 gauge and protected by the 16 gauge fusible link at the battery. The 12 gauge wires that are protected by the fusible link include the brown accessory-position wire and pink key-on wire that come from the key switch, and red always-hot wire, the A/C high-fan-speed wire, and the cigarette lighter wire. It's probably OK to be unfused, but it's also probably not a bad idea to use a fuse for some things.

[samkost]

dmjlambert,
Again that’s some great information.
I have learned a lot.
Thanks

[samkost]

dmjlambert ,
You posted and I just learned that the headlight switch has an internal circuit breaker.
Does this trip and reset itself or does this permanently damage the headlight switch needing replacement?

Keep the information coming! I’m learning a lot!
Thanks Sam

[dmjlambert]

I have heard there is an internal circuit breaker that automatically resets, but I have not experienced it myself. And now that I go looking, I can't find any definitive information about the existence of the internal circuit breaker. There is only forum mentions of it but no hard evidence that I can find. I think a good condition switch could be tested using 12 gauge wires and a 16 gauge fusible link, preferably when it is removed from the truck. Or somebody could take a switch apart and examine it. Or somebody who has deeper knowledge of the supposed internal circuit breaker could chime in here on this thread.