Simple wiring question.

[Mollysdad]

Power to the tongue jack.
The positive side is connected via the 10 ga. lead to the battery on the yellow crimp connector.
The negative lead is through the frame.

Where does the frame meet the negative battery connection?
I'm assuming there's a junction block where a battery lead meets the frame.

Since the only battery leads are the inverter and the converter, which lead is grounded to the chassis?

[uncle_bob]

Hi

Battery meets chassis back by the main thermal breaker bus. There's a black and a red wire off the typical battery box that heads into the trailer. So one pair for the inverter and one pair for "everything else.

Fairly close to the front of the trailer (exactly where depends on the model / layout) there is a DC power junction. The 7 pin umbilical comes in there and various DC loads fan out from there. Part of the setup is a ground bus bar. It has a wire heading off to the frame. The other part is a set of thermal breakers to protect this and that.

Usual disclaimers apply .... it's AS so who knows what they have done on this or that trailer "back in the day". The setup above is what they seem to have been doing for the last couple decades.

Bob

[Mollysdad]

Originally Posted by uncle_bob

Fairly close to the front of the trailer (exactly where depends on the model / layout) there is a DC power junction. The 7 pin umbilical comes in there and various DC loads fan out from there. Part of the setup is a ground bus bar. It has a wire heading off to the frame.

To put a finer point on my question, does the chassis ground buss get it's battery ground from the inverter pair or the converter pair?

I'm asking because I want to see what side leads to the jack.

[Mollysdad]

After staring at the wiring diagram for a while, it appears that the red and black pair that go to the converter is where the chassis ground happens.
The red goes into the converter, while the black first goes to the ground buss and then is distributed. One of the grounds is a white which then continues to the converter.
It matters to me because if you put a disconnect on the battery, I still want the jack to work. So to use the jack, reconnect the battery switch at the converter side. ( my disconnects use the black or negative lead.)
Make sense?

[Al and Missy]

Originally Posted by Mollysdad

After staring at the wiring diagram for a while, it appears that the red and black pair that go to the converter is where the chassis ground happens.
The red goes into the converter, while the black first goes to the ground buss and then is distributed. One of the grounds is a white which then continues to the converter.
It matters to me because if you put a disconnect on the battery, I still want the jack to work. So to use the jack, reconnect the battery switch at the converter side. ( my disconnects use the black or negative lead.)
Make sense?

Disconnecting the negative side makes sense from a safety standpoint, but perhaps not from an operational one. IF the battery negative(s) are disconnected, even a slip of a wrench on the positive terminal which contacts the frame is safe. It does, however, kill everything.

Careful with the use of color codes on wires. Part of the trailer wiring uses the AC standard where white is ground/neutral, as you discovered with the white wire to the converter ground. Black is often used a +12 in some of the trailers but I would have thought they would have converted to a DC standard by now.

I have a different philosophy. My jack does not work with the disconnect turned off. That makes it difficult for anyone to mess with the trailer while it is in storage. I didn't modify it, it came that way.

Al

[Mollysdad]

Originally Posted by Al and Missy

Disconnecting the negative side makes sense from a safety standpoint, but perhaps not from an operational one.
My jack does not work with the disconnect turned off. That makes it difficult for anyone to mess with the trailer while it is in storage. I didn't modify it, it came that way.

Thanks.
Without going too far into the weeds, I disconnected the black negatives instead of the red positives because they are longer and reached my switch without splicing in another section of cable.
However, this requires for me to pay attention to things like the breakaway switch and the jack power. In general, it will be my policy to have the switch "ON" any time I'm towing or using the trailer. "OFF" is for storage.

[UnklJoe]

The nice thing about standards is: There are so many of them to choose from!!!

[Mollysdad]

Originally Posted by UnklJoe

The nice thing about standards is: There are so many of them to choose from!!!

Ba-dum-pa.

I'm still thinking the switch on the negative side is best because it will force me to turn the switch on to use the jack. No jack, no towing. It also assures me the breakaway switch will have juice if needed.

Straight to the battery will be the Zamp connector which I'm using to provide power to the TPMS repeater. I'll still have to remember to unplug that one while parked.

[Al and Missy]

Originally Posted by Mollysdad

Ba-dum-pa.

I'm still thinking the switch on the negative side is best because it will force me to turn the switch on to use the jack. No jack, no towing. It also assures me the breakaway switch will have juice if needed.

Straight to the battery will be the Zamp connector which I'm using to provide power to the TPMS repeater. I'll still have to remember to unplug that one while parked.

I had similar thoughts about where to connect the power lead to the hydraulic actuator I added for my disc brakes. I decided to put it on the trailer side of the disconnect switch, since the jack doesn't work with it off I'll be forced to turn it on when I hook up.


Al