Circuit Breaker Amperage on L-110?


IHC in the early to mid-fifties.

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Post Thu Jan 31, 2019 7:10 pm

Circuit Breaker Amperage on L-110?

Does anyone know what the amperage rating is for the circuit breakers and terminal blocks on an l-110?

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Post Thu Jan 31, 2019 10:30 pm

Re: Circuit Breaker Amperage on L-110?

I did search and this is what I found. If you are using 12 volts, the breaker could be about 25 amps. If you are staying with 6 volts. the breaker rating will have to be about 50 amps.
I have several OEM IHC Cole Hersey headlight switches with the breaker. I am not going back to the shop this evening. If I remember I will take a picture and try go get some amperage information tomorrow.
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Post Fri Feb 01, 2019 8:24 am

Re: Circuit Breaker Amperage on L-110?

Great, thank you! I am staying with the 6 volt system.

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Post Fri Feb 01, 2019 10:53 am

Re: Circuit Breaker Amperage on L-110?

[quote="EmanM18"I am staying with the 6 volt system.[/quote]

Me too and I'll be adding a few inline fuses in the circuits. A one circuit breaker system is kind of scary. Lesser circuits shorting out can do a lot of damage before they will blow a 50 amp fuse or breaker!. For anybody using the one breaker original system I would say keep a fire extinguisher in the truck.
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Post Sun Feb 03, 2019 11:03 pm

Re: Circuit Breaker Amperage on L-110?

Binder Mike wrote:[quote="EmanM18"I am staying with the 6 volt system.


Me too and I'll be adding a few inline fuses in the circuits. A one circuit breaker system is kind of scary. Lesser circuits shorting out can do a lot of damage before they will blow a 50 amp fuse or breaker!. For anybody using the one breaker original system I would say keep a fire extinguisher in the truck.[/quote]
So what amp in line fuses are you going to use ?

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Post Mon Feb 04, 2019 4:17 am

Re: Circuit Breaker Amperage on L-110?

Off the top of my head 15 amp fuses for the tail lights and signals a bit higher for the heater blower motor and windshield wiper motor. Really to do it right I need to sit down and figure the current draw for the circuits I want to protect. Also keep in mind for any given gauge of wire it can only carry x amount of current safely before it overheats so wire size for a given circuit will also be an indicator of fuse amperage. If you have the shop manual the wiring diagram lists the gauge wire used in each circuit which is helpful.
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Post Mon Feb 04, 2019 9:11 pm

Re: Circuit Breaker Amperage on L-110?

Keep in mind that fuses or breakers are rated to protect the wire, not the load. As a result they are generally higher than the load, especially motors, to withstand starting current.

That said, it’s easy to calculate the load based on the formula Watts = Current x Voltage. Rearranging for a known wattage, Current = Watts / Voltage. So if you have a 30W light at 6V, it draws 5 amps. The actual operating voltage is around 7.1V, but you get the idea.

The shop manual unfortunately doesn’t include circuit breaker values, but this is what I did:

20A for high beams and low beams
15A for brake, tail and park lights
10A for the horn

Shop manual says the 6V wiper motor draws 4A on low and 3A on high. 12V draws half that. If the heater motor is more than that I’d be surprised. A 10A breaker should do for either.
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Post Tue Feb 05, 2019 4:43 pm

Re: Circuit Breaker Amperage on L-110?

Thanks everyone for the help.

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