Amperage of Brake Magnets and Size of Wire Used To Connect 7-Way Trailer Plug To Electric Brakes
Question:
How much much amperage does each electric brake magnet require? I am trying to figure out what size wire to run from the trailer plug to the electric brakes. Thanks
asked by: Tom H
Expert Reply:
On each individual electric brake magnet the amperage draw would be 3.0 to 3.2 max amps at 12 to 13 volts on 7-inch brake magnets and 3.2 to 4.0 max amps at 12 to 13 volts on 10 and 12-inch brake magnets.
The max amperage draw for the brake magnets on a single axle trailer (2 brakes) would be 6.3 to 6.8 max amps on a 7-inch brake system and 7.5 to 8.2 max amps on 10 and 12-inch brake system. The amps will be higher if using a tandem axle or triple axle trailer.
I am including a link to a FAQ page on Electric Trailer Brake Magnets that will show you how to test them and list the numbers I mentioned above.
On a 7-Way connector the suggested minimum wire gauge for the White (ground) wire, the Red or Black (power) wire, and the Blue (brake power) wire is 12 gauge. The minimum wire gauge for the remaining Green (right turn/brake) wire, the Yellow (left turn/brake) wire, the Brown (tail lights) wire, and the Purple (reverse light) wire is 16 gauge.

Product Page this Question was Asked From
Electric Trailer Brake Assembly - 10" - Left Hand - 3,500 lbs
- Accessories and Parts
- Trailer Brakes
- Electric Drum Brakes
- LH
- 3500 lbs
- Brake Assembly
- Manual Adjust
- 10 x 2-1/4 Inch Drum
- etrailer
more information >
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Jody P.
7/10/2020
I just put a brake controller on my Mercedes suv and curious how much current the controls require. Do I need an amplifier/booster or will this drive a two axel brake system?