What are these electrical things

[JeffreyG]

Sorting out my electrical system to add solar and move the batteries. I was looking at where I need to add breakers and fuses and located these boxes. These are where the main positive line comes from the battery and then goes to the convertor and the power distribution.


Are these fuses? I'd just pull one off and look but they are in a tight spot so I'm taking the easy path and asking.

[Centex]

Those are type-1 auto-reset thermal breakers. They will eventually trip on overload or fault then continuously reset/trip until the overload or fault is removed.

Personally I don't care for their lack of fault indication and continuous re-activation of the circuit if there's a fault, but they do have their place.

You may need to unscrew them to find the amp-rating printed on the side, but yep it's there

[tdf-texas]

Originally Posted by JeffreyG

Sorting out my electrical system to add solar and move the batteries. I was looking at where I need to add breakers and fuses and located these boxes. These are where the main positive line comes from the battery and then goes to the convertor and the power distribution.


Are these fuses? I'd just pull one off and look but they are in a tight spot so I'm taking the easy path and asking.

Auto reset DC circuit breakers.
https://www.amazon.com/MonkeyJack-Au.../dp/B077P9HJZ9

[7Gentex]

And the one on the right appears to be "bridged / bypassed" due to the manner in which the connections appear to be touching?

[rubicon327]

Originally Posted by 7Gentex

And the one on the right appears to be "bridged / bypassed" due to the manner in which the connections appear to be touching?

Good catch.

[JeffreyG]

Originally Posted by 7Gentex

And the one on the right appears to be "bridged / bypassed" due to the manner in which the connections appear to be touching?

Yeah, that's what I saw. Thanks for the comments all.

Since I have your attention, here is another question. ETI ran two cables to the negative terminal of the battery. One 2AWG cable direct to the inverter. The other one a 6AWG line to a bolt on the frame.

The converter and power distribution are also connected via their own grounds to the frame. But this means ETI is using the frame as an active conductor in the ground system. Does that strike you all as a best practice, vs. just directly connecting the battery negative terminal to the negative posts on the converter etc.?

[rubicon327]

Originally Posted by JeffreyG

Since I have your attention, here is another question. ETI ran two cables to the negative terminal of the battery. One 2AWG cable direct to the inverter. The other one a 6AWG line to a bolt on the frame.

The converter and power distribution are also connected via their own grounds to the frame. But this means ETI is using the frame as an active conductor in the ground system. Does that strike you all as a best practice, vs. just directly connecting the battery negative terminal to the negative posts on the converter etc.?

Hopefully the real electrical gurus will weigh in but in the rewiring of our 2010 trailer I found the main ground landed in a metal junction box (with 7 pin wiring) that was grounded to the frame. I thought Escape had changed this practice of using the frame as a conductor. The best practice as I learned from Tdf-Texas is for the 6AWG ground wire to go direct from the battery negative to the ground stud on the back of the power center. All DC grounds collect there including the main negative from the WFCO DC distribution board. This stud then has a single ground to the frame.

[7Gentex]

My head is hurting from trying to figure out what is what in that pic above.

And why are there basically what appears to be 2 breakers in "series"? (one after another) Different ratings?

Appears main line comes into the top right terminal (darker red big guy, though shorted), then off the bottom right and goes to the bottom left of another breaker, with 2 lines coming off that terminal, then a line comes off the top left terminal........

Or is the main feed the top left?

[CharlesinGA]

All of the crimps on the terminal ends are horrible. One appears to almost not be crimped. They all should have heat shrink on the crimped area, and yes that one is touching the other terminal.

No RV manufacturer is immune from poor workmanship.

Charles

[Brian B-P]

Originally Posted by JeffreyG

... But this means ETI is using the frame as an active conductor in the ground system. Does that strike you all as a best practice, vs. just directly connecting the battery negative terminal to the negative posts on the converter etc.?

If the electrical connections to the frame are done well, as they are in a typical car, this is standard automotive practice and works well. The way RV manufacturers typically do this, including Escape, it's an invitation to problems as the connections corrode.

[JeffreyG]

Originally Posted by Brian B-P

If the electrical connections to the frame are done well, as they are in a typical car, this is standard automotive practice and works well. The way RV manufacturers typically do this, including Escape, it's an invitation to problems as the connections corrode.

That was my feeling. Why ground to the frame outside the trailer where it will corrode when there is a ground terminal on the converter/distribution box?

Is there any problem with running a ground from the battery to the distribution box, and also running another ground to the frame? I note that the tongue jack is probably grounded to frame along with other items, so I need to maintain that ground connection to the battery, I figure.

There is a ground cable running from the converter/distribution box to the frame already as well. That's how the original ground was done.


I have a lot of questions, because I'm a mechanical engineer. I know enough about electrical engineering to be dangerous.

[TTMartin]

Originally Posted by Centex

Those are type-1 auto-reset thermal breakers. They will eventually trip on overload or fault then continuously reset/trip until the overload or fault is removed.

Personally I don't care for their lack of fault indication and continuous re-activation of the circuit if there's a fault, but they do have their place.

You may need to unscrew them to find the amp-rating printed on the side, but yep it's there

The one I added in place of the fuse for my Sprinter cigarette / power port has a Modified Reset Design. It stays tripped as long as there is power to the circuit. You reset it by turning off the circuit, or by turning off the ignition switch.

Bussmann CB1921-25 Type II MAXI Footprint Automotive Circuit Breaker (25 Amp)

[rubicon327]

Originally Posted by JeffreyG

That was my feeling. Why ground to the frame outside the trailer where it will corrode when there is a ground terminal on the converter/distribution box?

Is there any problem with running a ground from the battery to the distribution box, and also running another ground to the frame? I note that the tongue jack is probably grounded to frame along with other items, so I need to maintain that ground connection to the battery, I figure.

There is a ground cable running from the converter/distribution box to the frame already as well. That's how the original ground was done.

I have a lot of questions, because I'm a mechanical engineer. I know enough about electrical engineering to be dangerous.

You ideally want to get a direct connection of all your grounds to the battery negative via the ground post on the back of the power center as I described above. This post then has a single ground to the frame. I would eliminate the ground connection from the battery direct to the frame as it is unnecessary and could present future issues. Your tongue jack will still be grounded via your common ground point at the power center. It is more important in the A/V world than this application but you generally want a point of common potential for all devices and avoid multiple ground loops.

[Centex]

In the case of the original equipment DC electrical system on all Escape trailers, the frame is the negative return (aka 'ground') path for:

• Power jack(s)
• The charging (aka '+12V') feed from the tow vehicle 7-pin connector (the 'ground pin' on the vehicle 7-pin connector is wired via the umbilical to the junction box on the trailer with a short 'jumper' from that terminal in the junction box to the nearby trailer frame)
• The electric brakes (in both 'normal' and 'breakaway' operation)

Is that a correct and complete list?

[tdf-texas]

Originally Posted by JeffreyG

That was my feeling. Why ground to the frame outside the trailer where it will corrode when there is a ground terminal on the converter/distribution box?

Is there any problem with running a ground from the battery to the distribution box, and also running another ground to the frame? I note that the tongue jack is probably grounded to frame along with other items, so I need to maintain that ground connection to the battery, I figure.

There is a ground cable running from the converter/distribution box to the frame already as well. That's how the original ground was done.


I have a lot of questions, because I'm a mechanical engineer. I know enough about electrical engineering to be dangerous.

Best practice is to have one and only one ground connection to the battery. On an Escape, that is usually done at the ground stud on the back of the converter which is grounded to the frame. The ground wires that I find on the 19 and the 17 to the battery is a bad practice for the reasons both Brian B-P and rubicon327 gave - corrosion issues and ground loops. On a car, there is ONE ground wire from the battery to the frame - any additional grounds would create ground loops so it's not done.

The ground in the 7 pin box is for the trailer running lights, the brake lights, the brakes, and charging current from the TV. All of these circuits are powered from the TV - not the trailer and have a negative wire run spliced into each device wiring back to the 7-pin JB and the TV negative. The negative terminal in the 7-pin is also tied to trailer/TV ground.

Everything else in the trailer that is 12v references back to the converter fuse panel which is powered by either the converter power supply/solar/battery. As such, the only ground connection for these circuits should be the converter ground lug located on the back of the converter.

A 6 ga negative wire run from the battery to the converter ground stud and removal of the ground wire to frame attached to the battery would be the way to go.

[JeffreyG]

Originally Posted by tdf-texas

Best practice is to have one and only one ground connection to the battery.
A 6 ga negative wire run from the battery to the converter ground stud and removal of the ground wire to frame attached to the battery would be the way to go.

Thanks much, that is what I'm going to do.


Incidentally, I found one of the four nuts on that dual breaker set in the picture I posted was stripped.

[MVA]

Originally Posted by Centex

In the case of the original equipment DC electrical system on all Escape trailers, the frame is the negative return (aka 'ground') path for:

• Power jack(s)
• The charging (aka '+12V') feed from the tow vehicle 7-pin connector (the 'ground pin' on the vehicle 7-pin connector is wired via the umbilical to the junction box on the trailer with a short 'jumper' from that terminal in the junction box to the nearby trailer frame)
• The electric brakes (in both 'normal' and 'breakaway' operation)

Is that a correct and complete list?

Alan,

I believe the trailer exterior lights (running lights, brake lights) also use the frame as a return back to the ground on the 7-pin.

[Centex]

Originally Posted by tdf-texas

.... A 6 ga negative wire run from the battery to the converter ground stud and removal of the ground wire to frame attached to the battery would be the way to go.

Tom, in that scenario should the 'ground' wire from the converter ground stud to the frame also be upgraded to 6AWG?

Maybe not since that 'ground to frame' is really only a negative return path to the battery from the tow-vehicle charger, jacks, and breakaway brakes, not actually a protective low-resistance path-to-'earth' in case of human body fault?

EDIT - deleted paragraph based on new info learned in post #23. Thank You, tdf-texas yet again!

[Centex]

Originally Posted by MVA

Alan,

I believe the trailer exterior lights (running lights, brake lights) also use the frame as a return back to the ground on the 7-pin.

Perhaps, I've not investigated the 'DOT lighting' circuits on mine. That would mean each of those lights must have a jumper wire from the fixture installed in fiberglass shell to the frame local to them in some manner.

Now I'm curious and will have to search-out the return path for those 'DOT lights'.

(DOT = Dept of Transportation; 'DOT lighting' being my catch-all term for those lights you mention, maybe there's a better term?)

[rubicon327]

Originally Posted by MVA

Alan,

I believe the trailer exterior lights (running lights, brake lights) also use the frame as a return back to the ground on the 7-pin.

Originally Posted by Centex

Perhaps, I've not investigated the 'DOT lighting' circuits on mine. That would mean each of those lights must have a jumper wire from the fixture installed in fiberglass shell to the frame local to them in some manner.

Now I'm curious and will have to search-out the return path for those 'DOT lights'.

(DOT = Dept of Transportation; 'DOT lighting' being my catch-all term for those lights you mention, maybe there's a better term?)

I don’t think this is the case. Older trailer with some rewiring but you can see a ground (white) in the lower right comes back on the stop/turn/tail harness in the trailer. Most trailers have the junction box outside now but the concept is the same. This is an easier and much preferred way to handle it. Otherwise every light would need a penetration near the fixture through the floor to the frame.