Electric brake wiring question

[dward51]

Replacing whimpy 14ga Lippert wiring to the brakes with brand new tinned marine grade 10 gauge wiring. Current setup is one brake line that splits at the axles. Will be replacing with 4 independent "home run" brake lines for both the positive and return ground (no frame grounds for the brakes - all hard wired back to distribution bus terminals at the front of the trailer). This is on a 24 1/2' trailer so the run is not long to start with. Brake backing assembly is brand new Dexter self-adjusting, so basically everything is new on all 4 brakes.

So my question is, does it matter if each run from my brake distribution terminal strips at the front of the trailer to each brake assembly is not the exact same length? With the overkill in wire size at 10ga, the voltage loss should be virtually 0, and the amperage per magnet is only around 3 amps max (10 ga wire is rated for 30 amps). So if one home run is say 8' total and another is 14' total does it matter with that setup?

If I try to make them all the same physical length, somewhere I'm going to have to loop up a good bit of wire for the front axle as compared to the rear. That just seemed like a waste of wire since the gauge is larger than needed already. With the cushion in wire size vs the low amperage on each line (one set of lines per brake hub), it just seems more practical to me to just run them the length they need to be with a little extra in the underbelly for future maintenance if I need to replace a magnet or brake assembly later on.

Just wanted to see what the group thought.

[clr]

I would say that the different length of runs with that gauge of wire would not make any difference. I know when I had electric drum brakes on my unit that will max breaking by the manual lever I would measure 4 amps at the brake. I know that Prime Time ran two 14 gauge wires with return to only one side of the axles, they then used the wire inside the axle to cross to the other side brakes. With your home run of the brake wires I see no problems with what you are planning.

[SlowrideHD]

You could have one wire at 90 feet and others at 5 feet with that gauge and it wouldn't make any difference.
Overkill much?

[babock]

Not one bit. The brake magnets only draw around 4A each.

[dward51]

That's what I thought. I'll just run the lengths I need and save the extra.

Thanks

[lorenc]

FYI the “3M” brand crimp -on brake wire connectors that FR uses at each wheel are not water proof. My 2014 Surveyor Pilot had some intermittent brake failures this winter in Florida and after two days of testing wires and connections and integrated brake controller I finally hired a mobile RV repair man and $720.00 later the last thing he checked were those connectors and found they had dirt and moisture inside causing the problem. Snip snip and a few waterproof butt connectors and I was on the road.

[babock]

Originally Posted by lorenc

FYI the “3M” brand crimp -on brake wire connectors that FR uses at each wheel are not water proof. My 2014 Surveyor Pilot had some intermittent brake failures this winter in Florida and after two days of testing wires and connections and integrated brake controller I finally hired a mobile RV repair man and $720.00 later the last thing he checked were those connectors and found they had dirt and moisture inside causing the problem. Snip snip and a few waterproof butt connectors and I was on the road.

Yep. Those things are worthless.

[pdqparalegal1]

Originally Posted by SlowrideHD

You could have one wire at 90 feet and others at 5 feet with that gauge and it wouldn't make any difference.
Overkill much?

Agree. This isn’t rocket surgery. 🙄

[dward51]

I'm not using those crimp lock connectors.

I'm using marine style crimp connectors with adhesive lined heat shrink built in (from Genuinedealz.com), and the proper heat shrink connector crimping tool. I'm then sleeving the wire in split wire loom for extra protection. Outside the underbelly the wire loom will also be wrapped in 3M exterior electrical tape for an added measure of protection. I'm also sleeving all the wiring in the under belly with wire loom to protect it from any potential vibration chafing, as well as securing it to the steel cross framing with tie wraps.

[madatme]

i agree with everyone else, What I do want to know is with the bigger gauge wiring being used and better current/voltage capability did you half to turn down your brake controller setting or is it the same?

[dward51]

Originally Posted by madatme

i agree with everyone else, What I do want to know is with the bigger gauge wiring being used and better current/voltage capability did you half to turn down your brake controller setting or is it the same?

I would think not, but I will find out. Still working on other things and the trailer is up on jacks in the driveway.

One of the reasons for the rewire is I was having an intermittent brake problem. It was not the ground, and I suspect the flaky scotch-lock connectors (which are not dirt or water proof). It ended up being a "might as well" thing to upgrade the wire gauge along with replacing the brake backing assembly with self-adjusting units. I even considered EOH, but the upgrade was a lot less than converting to EOH which was also overkill for this size trailer.

That's the problem with projects, one "might as well" leads to a half dozen others, and it never seems to end. Going to be a damn fine trailer setup when I finish.

[exscream]

The voltage drop on 10 feet of 14 gauge wire, at 3 Amps is 0.08 volts. This would have no effect on any of the brake performances. Other factors, like friction, adjustments, varying coil resistances or bad connections, would more likely make a difference.

[dieselguy]

I've been down this road before ... I may even have the T shirt. I understand your thoughts on going with a larger gauge wire, but going to 12 or on up to 10 gauge wire itself will provide no noticeable difference. You'll find with using better wire connectors, or soldering the joints, making sure there is no issue with the wire running inside each axle tube, making sure you have a good solid ground, and carefully checking out your pigtail going to the TV ... the 14 gauge wire that comes on tens of thousands of TT's and fivers will prove adequate.

[rsdata]

10 gauge is stiff and hard to work with ( maybe you are using multi-strand), and unless it is FREE I would use more then adequate 12 gauge...

[babock]

Originally Posted by rsdata

10 gauge is stiff and hard to work with ( maybe you are using multi-strand), and unless it is FREE I would use more then adequate 12 gauge...

Me too. The reason to use a heavier gauge is to help limit damage instead of the smaller wire.


I know the OP is doing homeruns which is way more important. No splices along the way is the best improvement even if sticking with 14 gauge.

[TitanMike]

All this work and yet the wires from the tow vehicle to trailer (7-wire cord) are no larger. The blue trailer wire is #12 and the white "ground/negative" is #10.

I'd focus on the connectors and if the factory wiring is actually #14 maybe then upsize to #12.

Most issues regarding lack of braking on trailers are mechanical in nature. New brakes that haven't seated, old brakes that are out of adjustment, grease contamination, and sometimes just plain wet from driving in the rain.

On that last point, drum brakes become very ineffective when wet and since most motor vehicles now use disc brakes people tend to forget this. Problem can be mitigated some by manually applying the trailer brakes lightly when going through large puddles and if driving on rain covered roads apply the brakes several times manually as you are approaching a known stop.