What Size Circuit Breakers Can be Used on a Trailer for Electric Jack and Brake Functions

Question

Question:

I have two circuit breakers mounted on my trailer frame near my battery box. They are wired in series output lug of breaker #1 wired to input lug of breaker #2 and each breaker has another wire on the output lug. I assume that one breaker is for the electric brakes and the other is for my electric tongue jack I have not traced the wires yet. The problem is that I need to replace the existing breakers because the housing on both is broken and being held together with a zip tie, but I have no way of telling what size they are. I have looked closely and I do not see any amp rating. The only number visible is on the metal contact plate, inside the breaker between the terminals that has U-21 stamped on it. How can I tell what size they are so I can order replacements?

asked by: Jim

0

Expert Reply:

If those circuit breakers are indeed for the jack and the trailer brakes then they are likely redundant since the 12 volt circuit and brake circuit are already circuit protected on the vehicle side. Electric trailer jacks also usually have an internal circuit breaker and/or in line fuse. If you want to replace them you can.

If you can verify what they go to as the jack and brakes then jack the specs on the jack to determine its amperage draw. Usually electric jacks on trailers are rated to pull up to 30 amps so you can use a 30 amp circuit breaker # PK54530. For the brakes, since most brake controllers will use either a 20 amp or 30 amp circuit breaker (depending on how many brake assemblies there are) you can just go with another 30 amp breaker.

It is also possible that the circuit breakers were there for some kind of winch. The way you describe it sort of sounds like the circuit breaker sets winches use such as # SW87-22873-16 for example. I anticipate that the mystery of the breaker functions will be solved once you can verify where the wires from them lead.

expert reply by: Michael H

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Answer 1

That will depend on the amount of brake axles your trailer has. . The 20 amp breaker like #9506P is for 1 and 2 axle brakes, and the 30 amp like part #38630 is for 3 and 4 axle brakes

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Answer 2

Circuit breakers can have current run through them in either direction. The #9506P just needs be wired between the battery and the 12 volt power circuit of your brake controller. The basically you would run from the black wire on your controller to…

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Answer 3

The 12V feed from your tow vehicle's 7-Way connector carries enough current to maintain a charge on your trailer mounted battery, but it does not have enough to actually charge up a depleted battery. Since the battery will really only get a…

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Answer 4

On GM vehicles of that vintage, the 12-V pin should be hot regardless of whether the ignition is on or not. If it isn't showing voltage even with the ignition on, you're almost certainly on the right track thinking it's a…

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Answer 5

Yes, 14 gauge wire seems too small. I would go with 10 or 12 gauge. For 10 gauge you can use #10-1-1 and for 12 gauge use #12-1-1. These wires are sold in increments of 1 foot. So if you needed 20 feet of wire you would enter 20 in the quantity box.…

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Answer 6

We definitely know about the issue you are referring to. We have just the part for you! Furrion recently came out with a brand new adapter for your 2022 GMC Sierra 1500 Limited to work with your camera system. The part you need is the 7-Way Vehicle…

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Answer 7

According to the Lippert Service Manual for the Lippert Electric Trailer Jack #LC285318. "Maintenance 1. Before each use, inspect the Power Tongue Jack and replace if bent or damaged. 2. If wiring is connected to battery terminal, inspect at…

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Answer 8

Discovering why the trailer brakes are not getting power will be a process of elimination. I am not aware of what you have and have not checked, so I will describe the whole troubleshoot process. Start with the brake controller itself. Is it properly…

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Answer 9

The first error code, SH, you are seeing on the Prodigy Brake Controller (instructions linked below) means the brake wire sees a short circuit during idle condition. The second code, OL, indicates an overload condition during operation. For the first…

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Answer 10

If the brake controller is connected to the 2003 Chevy Silverado tow package port (to the left of the brake pedal, second port from the left, top row) using Tekonsha Wire Replacement, #3015-P, or a similar harness, and the truck came with a factory…

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Answer 11

There are several ways that you can cut off the power to your trailer brakes. The easiest option would be to simply unplug your brake controller. If the brake controller is disconnected, the brakes will not receive power. If your brake controller was…

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Answer 12

If you are using the Wiring Kit #5506 to install the Tekonsha Prodigy P2 #90885 then you will want to use the 30A breaker on the power wire for the brake controller. I have attached a helpful article and a picture that you can use for the…

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