Troubleshooting Voltage Drop to Second Trailer's Brake Assemblies

Updated 04/11/2024 | Published 04/10/2024

Question:

We have two trailers that hook together so together the total length is approximately 50. Each unit has two axles so thats 8 brakes all together. We used 8 gauge wiring from the receptacles to a junction box and then one 10 gauge wire down to each axle for the brakes. With 13 volts at the front of the lead trailer we have 4.5 volts at the rear of the second trailer. Was the 8 gauge wiring the proper gauge wire from the receptacle? Instead of one 10 gauge wire to the axle should we have run one 10 gauge wire to each brake from the junction box. Need the help of some experts!

asked by: Eric F

Expert Reply:

Hey Eric, with that much voltage drop the issue is that the wire length added way too much resistance. The only solution is heavier gauge wire everywhere most likely. I would think that 8 gauge wire would be pretty close if wired everywhere but you might be looking at needing 6 gauge since there's just so much wire. You also need to make sure the ground wires are of an equal gauge too.

expert reply by: Jameson C