Trailer Brake Output Circuit Gauge Wire Recommendation to Prevent Amperage Drop

Question:

My LQ horse trailer harness is 14 gauge and about 45 ft long to the brakes. The measured current is 13 Amps. What I am finding is the voltage drops to about 9 volts. Is this normal. Should my brakes work ok as they are drawing 13 Amps. 4 magnets?

asked by: Charlie

Expert Reply:

A small voltage drop is normal for long runs of wiring but if you are seeing a drop of 4 volts that would be an indicator your wiring has too much resistance. So what you'd want to do is replace all of the brake output circuit on your trailer wiring with 10 gauge wire like part # 10-1-1 (sold by the foot) as the heavier gauge wire will carry the amperage and voltage better with a considerably lower voltage drop.

14 gauge wire is too light for the brake output circuit. Especially at that long of a length.

expert reply by: Jameson C