Best method for connecting brake wiring - Tips

[Yoda]

I thought I would ask the question separately.

On my new axles non of the brake wiring is connected. Wiring does go through the tubes, but non of the backing plate wiring is connected up.


The wiring appears to be 14 gauge. For the curb side I was going to use heat shrink Butt connectors with additional heat shrink over the connection when done. I have not checked if the wiring is color coded or any indication of a positive/negative wire. Are the coded?

Now for the street side where the trailer wiring is connected I wanted possibly a way to disconnect, in case I need to drop the coroplast belly. I was thinking of using a Delphi connector above or below the coroplast. Somewhere I have these stored away.



I would do the 3 way splice using butt connectors and heat shrink tubing as described before. Again do I need to match up the wiring to be the same as the other side (color or wire rib)? My existing wiring is connected using bulb connectors I believe


Existing wiring

Now I have read the wiring in the brake is just to the electromagnet and the polarity is not critical (closed loop, no ground), but wonder if the polarity across the magnets (both sides) and between axles should match up. Also should I pull better wire between the brakes (through the tube) or is the Dexter wiring good enough - its all open and easy to get to right now.

All thoughts are welcome here as I want to get this right the first time.

Thanks Keith

[TedS]

There is no polarity to the electo magnets. Pick one way and stay consistent. You could use blade and spade connectors for disconnects.

[Yoda]

There is no polarity to the electo magnets. Pick one way and stay consistent. You could use blade and spade connectors for disconnects.

Thanks Ted.
Blade and spade would make it easy. Hadn't thought of that I can also cover with heat shrink so they can't come apart unless I take them apart.

Keith

[Yoda]

Ok Huston we may have a problem brake wiring size. I was reading up on the proper wiring and connectors used and ran across the Dexter service manual.

Dexter brake manual indicates I should have a minimum of 12awg wiring ( Page 11 here; https://www.dexteraxle.com/user_area...ice_manual.pdf) I know the trailer wiring is not that big - probably 14 awg. I need to look once the snow melts. However per the blue sea chart http://assets.bluesea.com/files/reso...on_chartlg.jpg 14 is OK if the 10% voltage drop is allowable as all 4 brakes should draw less then 15A - more like 12A if I remember correctly, Dexters 12 awg is more fitting within the critical 3%.

Does anyone know for sure what I have as far as the brake wiring GD used. Now I will say the wiring on the new axles is thicker than what I have now, I guess I need to look and see if there are any markings. It looks to be 14 awg from the magnets and the cross over, but again I need to look closer. HMMM I am wondering if my new bore scope might help with magnifying the marks so I can actually see them.

Thoughts - or is this really a non issue?

Thanks
Keith

[TedS]

Each magnet will draw only about 3 amps, max.

[TedS]

From etrailer :

[TedS]

From Dexter:

Dexter122.pdf

[Yoda]

Each magnet will draw only about 3 amps, max.

Correct - found that on page 21 of the PDF
Whats interesting is it appears GD ran the ground wire forward and tied into the bundle up front. Ill need to check that and size. E-trailer says to just ground that wire to the frame. I also read an e-trailer answer to use 10 awg wire for brakes with a link to thier wire.

Iron Bear confirmed the axle/magnet wiring is 14 awg and to use butt connectors and heat shrink tubing (that what they do) I will confirm when I get a chance.

More to learn

Thanks for the help Ted
Keith

[Country Campers]

I would not ground the brakes to the frame. I do not like any 12 v dc ground to be on anything other than the battery. Back in the olden days trailers use to get their ground thru the hitch and ball, remember those blinky lights going down the road. Especially with trailer brakes return the ground back to the battery or ground post that is connected directly to the battery.

Brian

[Yoda]

From Dexter:

[ATTACH]n108693[/ATTACH]

Thanks looks the same as what I found
Soooooooo
Using the blue sea chart at 12 amp (3% critical) and with the total wire run about 25 to 30 feet to the brakes from the truck connection, the main wire run and ground wire should be 10awg - 12awg if I allow the 10% voltage drop. In looking, most 7 way RV cords have a 12 awg blue brake wire in the bundle. Hmmmmm Makes me wonder if the 3 axle trailers have larger wiring in the 7 way cable and if they are all the same with the trailer wiring pulling up to 18 amps. BTW looking at Dexters wiring chart (page 11) it matches the blue sear chart if you use the 10% table. Rob Cate&Rob do you remember the wire sizing you found when doing your disk break change?

Keith

[Yoda]

I would not ground the brakes to the frame. I do not like any 12 v dc ground to be on anything other than the battery. Back in the olden days trailers use to get their ground thru the hitch and ball, remember those blinky lights going down the road. Especially with trailer brakes return the ground back to the battery or ground post that is connected directly to the battery.

Brian

Good thought Brian - I agree. The ground (return path wire) currently runs to the front and is now connected to a ground bus bar that is attached to the frame and also attached to the negative battery cable. What I don't know is if GD up sized the wire for the brakes - need to check

Keith

[Country Campers]

I believe that the wiring from the front to the brakes is 14 ga. The wire that goes from side to side on the axel is the same. I have thought about running 12 or 10 gage back to the brakes and upsizing going side to side but have not done that yet. From a recent visit to GD I did ask a Tech about the brakes amps, he stated between 3-5 amps per wheel with 3 being the most common number seen.

Brian

[TedS]

Just a reminder that the wire circuit length includes both the out and back for total wire length. Source to load and back to the source. So 10% voltage drop from 12 volts is 1.2 volts, 0.6 volts drop to the load(magnets) and 0.6 volts drop from load back to source. That allows 10.8 volts drop across the magnets, so they will not each draw max 3amp current.

[Yoda]

Just a reminder that the wire circuit length includes both the out and back for total wire length. Source to load and back to the source. So 10% voltage drop from 12 volts is 1.2 volts, 0.6 volts drop to the load(magnets) and 0.6 volts drop from load back to source. That allows 10.8 volts drop across the magnets, so they will not each draw max 3amp current.

Ted
I agree. Its about 15' from the plug to the rear axle so using 30': total run I should probably upgrade to 10 awg. However the plug cord is 12 awg for the blue wire. There is a 10 awg (positive battery feed) in it. The question is do I leave the plug wiring alone and just go to 10 awg from the junction box to the axles and stay withe 14 awg installed in the axles, or upgrade the cross wires to 12 awg or just do 12 awg everywhere. I think I need to sleep on it and do some checking on exactly what I have and the actual distances. It a good time to wire in my new 7 pin cord anyway that a got a few years back.

The cans of worms I keep opening up - Does it ever end? This does explain why I need such a high initial gain on my existing brakes. At lease everything is exposed and easy to get to.

More to ponder - at least I know the answer to life the universe and everything - 42

Keith

[Cate&Rob]

Hi Keith,

The original brake wiring is considerably smaller gauge than 14. I would guess maybe 18. See the attached picture where I cut the wires going to the electric brakes to re-route the signal to the EoH actuator. BTW, those Weather Pack connectors are a far better choice for any electrical connection that is in the weather, than spades even if they are covered with heat shrink.

Rob