Thread: Trailer Brake Wire Size

I fitted a 12 pin "flat" plug and receiver for the camper (from Jaycar IIRC) which has several pins of a larger diameter for heavy current draw (i.e. electric brakes). I think I used 10 gauge for the braking circuit, including the cable from the (P3) controller under the dash to the rear bumper mounted socket. Probably overspecc'd but it was handy and certainly does the job!

around 5-6amps per brake

Originally Posted by Pedro_The_Swift

around 5-6amps per brake

That what I would have thought - there is no way the standard offering in trailer electrical cable is going to carry that at a full 12v when required over the distance.

Garry

I'm pretty sure the BSL is running on the edge cable wise,,

I'm not even sure the 12 pin plug is rated to 20A
must check that one day

Trailer cable comes in different ratings, Narva 5874 cable is nominal 4mm 7 core cable rated at 15 amps, should be available from a decent sparkie shop or truck parts place. Or you could add a 4mm 2 core to your el cheapo 5 core using spiral wrap.

Originally Posted by bee utey

Trailer cable comes in different ratings, Narva 5874 cable is nominal 4mm 7 core cable rated at 15 amps, should be available from a decent sparkie shop or truck parts place. Or you could add a 4mm 2 core to your el cheapo 5 core using spiral wrap.

For sure there are ways around it - but the basic cable supplied and plugs etc on most trailers are really not up to scratch - makes me wonder how many trailers are not getting full braking capacity in emergency stops where a full 12v+ should be getting to the brakes.

Garry

Originally Posted by garrycol

For sure there are ways around it - but the basic cable supplied and plugs etc on most trailers are really not up to scratch - makes me wonder how many trailers are not getting full braking capacity in emergency stops where a full 12v+ should be betting to the brakes.

Garry

I suppose you could rig a volt meter to the brake controller to see what the full braking output voltage actually is, allowing for battery voltage being as high as 14V.

I agree many brake wiring cable sizes are undersized but the brakes come on anyway. Is there any roadworthy checking of trailer braking efficiency?

We just went through a 1st van rego (not renewel ) and I was hoping there is some form of brake test,, but no.
not even a handbrake check,, i know cos the handbrake doesnt work on ours. All they do is measure the van.

edit; The actual rego inspection is done by private company, in our case Trailaway here in Toowoomba,
a gas valve was replaced,
did they drive test the brakes? who knows,, and how do you test ALL 4 are working?
apart from physically seeing all 4 wheels lock up?