who is correct ?

Cuddles · PETERBOROUGH, ONT

who is correct ?

jarvis1 · COBBLE HILL, BC

LGKustoms is out here on the Island.
They do some nice work.

123pugsy · MARKHAM, ONT

A circuit breaker's job is to protect a wire from overload.
A 10 ga wire is rated to 30 amps. If a feller's electrical items are more than 30 and less than 40, the 10 ga wire can overheat without a 40 amp breaker popping. A 100 amp won't pop for sure.

It's not likely though, as everything is usually not on at the same time.

Wire size is key to any circuit breaker or fuse.
So, you figure out how many amps you want to run through a certain sized wire, going thru an oversized breaker, that may not trip until the wires get so hot, they melt and short to ground.

Automotive may be different a bit, but that's the theory on breakers. (same as fuses)
They are both over current protection devices.

Cuddles · PETERBOROUGH, ONT

So the 100 amp breaker he instals in the video is definitely incorrect if I understand you right. Wire size is crucial and wire length helps determine wire size. I think I get that ok. But this guy teaches wiring in a video on youtube and he is wrong to use a 100 amp breaker. For a novice like me, he is dangerous. I bought the 100 amp breaker and now I have a 40 too. I am glad I learned in time. Thank you pugsy.

Lightspeed Mike · BELLEVILLE, ONT

Pugsy is correct. His whole wiring harness will melt before that 100A breaker pops.

shag766 · FOXBORO, ONT

Lightspeed Mike wrote:

Pugsy is correct. His whole wiring harness will melt before that 100A breaker pops.

-X2

123pugsy · MARKHAM, ONT

Wire size is determined by amperage draw of what is running.
Wire length does not determine it, by it does add to it like a trunk mounted battery and wire running all the way to the front of the car will bump it up a gauge.
Small wires like for taillights and stuff are already over sized, so not something like them.

shag766 · FOXBORO, ONT

You really don't see anything much over a 30amp fuse or breaker in any form of 12 volt automotive use.

Cuddles · PETERBOROUGH, ONT

And yet the guy making the video is well regarded by many on the west coast. Apart from the breaker issue, he makes a great series of videos to learn about wiring a car from scratch.
Thank you guys. I listen to what you advise. Should I buy another breaker and get 30 amp this time ?

123pugsy · MARKHAM, ONT

I would run a 10 ga wire to a 40 amp breaker.
Like I said, not everything runs at the same time. Bigger is better as you don't want it tripping out while you're driving.

The guy doing the video could have calculated all his current draws and been well within the 10 ga wire's amperage limit.
In that case, he's not "wrong" as there wouldn't be enough amperage draw to melt his 10 gauge feeder.
So, there's that too.

Now, if a guy sold a car like that, and someone else added a bunch of stuff to it, thinking he had the same power a 1960's bungalow had, there could be some melt down happening.

Cuddles · PETERBOROUGH, ONT

Thank you Pugsy. I ran a 10 gauge wire and put in the 40 amp breaker and the battery is only about a foot from the fuse panel. Trying to make everything correct.