Where is the Negative Bus Bar?

[CampingProf]

I'm trying to hook up a new 12V DC fan in my Sunline RV with a Magnetek 6300 Series 6332 (newly upgraded with the PD4600 converter and DC distribution panel). It's pretty clear where to hook up the positive wire on the distribution panel. But where does the negative wire go?!

I've attached an image of everything totally taken apart in my quest for a negative bus bar. Can anyone help?

[JohnB]

I do not know about yours exactly, but your pic helps show that Sunline did about the same 12 VDC buss bar thing on yours that they do on the newer campers.

Here is what I see and how Sunline did the newer campers.

The 120 AC neutral uses sold white wires. They used solid-wire Romex cable for the 120 AC. That AC neutral buss bar is in your picture at the bottom of the power center. NOTE: heads up, do not tie the bare earth ground wires OR 12 VDC negative white wires to that AC neutral buss bar. Earth ground and AC neutral in a camper have to be separate. The EE Code treats a camper like a big appliance. If this gets mixed up by accident, you will trip any GFIC you plug the camper shoreline cable into.

The 12 VDC Negative wires use "stranded" single white wires. The 12 VDC negative is common on purpose with trailer chassis and earth ground. Just do not mix 12 VDC negative with AC neutral, as they are not common to each other. Now, where the heck did they put the 121 VDC negative buss bar?

Pull out the power center a little more; look behind it in the wall compartment cavity, and you should see an aluminum bus bar with white stranded wires and a bare solid copper wire heading to tie the trailer frame to create chassis ground. Odds are, they screwed the DC negative buss bar to the floor or a wall. There is just one heavy white wire from that bus bar to the DC fuse block where the power converter negative wire ties in. All the internal to the camper DC negative wires do come back to the power center "area", just not inside the power center, but outside the power center.

Under the camper, upfront by the frame header, there "may" be another 12 DC negative buss bar to tie the DOT lighting negative wires to the LP gas line and the battery heavy white negative wires. They also tie the chassis frame to the battery 12 VDC negative there.

If you can't find the inside 12 VDC buss bar, take more pics behind the power center enclosure in the wall cavity and we can hunt with you.

Hope this helps

John

[CampingProf]

This is on the floor of the camper, vaguely behind the electronics panel. Did I find it?

[JohnB]

Originally Posted by CampingProf

This is on the floor of the camper, vaguely behind the electronics panel. Did I find it?

Yes, you did! Good hunting. .

You can see the bare solid copper wire that, if you follow it, goes between the earth ground bus bar the shoreline cable connects to, goes through one lug of the 12 VDC bus bar, and then heads outside the camper to attach to the steel trailer frame. And the big heavy white wire would return to the converter power supply DC negative/common and the battery negative. The smaller white single-stranded wires are DC commons from the fused DC circuits.

Since you are upgrading, consider replacing that totally filled buss bar with a larger one so you are not doubling up on screw terminals. Home Depot and other stores that sell electrical supplies have them.

Here are some that will work.
https://www.homedepot.com/s/bare%20buss%20bar?NCNI-5

You are doing great work, good for you.

John

[CampingProf]

Thank you John for all your help! I really appreciate it.
And, yes, I'll order the replacement bus bar. Thanks for the suggestion — they're already double or tripled up. And I'm adding a new wire.

Thanks again. I couldn't have done it without your advice.

[JohnB]

Hi CampingProf,

You are very welcome. We are here to help as we can.

Your pictures and posts about this will help many others in the future. Thank you for passing this along.

Thanks

John

[CampingProf]

I ran into a problem trying to replace the bus bar. There's a dark green wire that passes through the bus bar. It seems to be stripped a little where it contacts the bar. Can I cut that wire and attach both ends to this new bus bar? Also, one of the white wires is twice as thick as the others. Should I do anything different with that wire? Maybe place it in the "block" thing on the top?

[JohnB]

Originally Posted by CampingProf

I ran into a problem trying to replace the bus bar. There's a dark green wire that passes through the bus bar. It seems to be stripped a little where it contacts the bar.

Can I cut that wire and attach both ends to this new bus bar?

Also, one of the white wires is twice as thick as the others. Should I do anything different with that wire? Maybe place it in the "block" thing on the top?

Great pics! we can see exactly what you are talking about.

In this pic,


Yes, a solid copper wire passes through the bus bar is a ground wire. The end that goes down through the floor bolts to the trailer metal frame. The other end goes up into the power center on the incoming earth ground buss bar.

From what I know, in a camper, Yes, you can cut the solid wire and insert each end under a separate screw in your new buss bar since you have lots of extra terminal spaces. I would clean up the tarnish on the wire ends before putting them into the terminal strip to make better contact. In this case, of a camper that has DC negative and earth ground common with each other, I do not know of an EE code that requires a continuous wire between the chassis frame and the incoming earth ground buss bar. If someone else has some input on this, please chime in.

If you want to keep the bare wire continuous, then unhook the bare wire on the incoming shoreline cord ground wire buss bar, pull the wire back enough to get the bare wire out of the old buss bar, and slide the new buss bar down the wire and hook the wire back up to the incoming ground buss bar.

The heavy white wire is the DC (-) negative wire that runs to the negative wire on the power converter board. Now, does that larger white wire go into the large lug on top of the bus bar? The answer I have is, it depends. That large lug is made for a large wire. The OD of the wire hole circle is big for a big wire. Sometimes, they stamp in the side of the block the awg size of the wire that will adequately clamp under the large screw. If it is not stamped, it is in the manufacturer's spec sheet. You do not want to put too small a wire in that large hole as the screw may not tighten against the wire correctly, the screw may hit the side of the hole circle and not clamp the small wire. So, yes it depends if you can use that large lug.

But, there is something else that needs to be looked at and you may need to increase the awg rating of that large white wire.

You stated this

I'm trying to hook up a new 12V DC fan in my Sunline RV with a Magnetek 6300 Series 6332 (newly upgraded with the PD4600 converter and DC distribution panel).

I looked up the 6332 Magnetek converter, and it was listed as 32 amps of DC power. The larger white wire Sunline used from the power converter negative to the buss bar would handle the 32 amps.

You are upgrading to an excellent PD 4600 series power converter and DC distribution panel. But, the 4600 series is made:

Model PD4635 (35 Amp)

Model PD4645 (45 Amp)

Model PD4655 (55 Amp)

We do not know what amperage power converter you have. The reason for bringing this up is that the large white wire we are talking about needs to have an AWG and class of insulation rating to handle the full load of the power converter, whatever it is. Sunline put in a large enough wire for the power converter at the time, but your new converter may be larger, which is OK, but you need to check the size you have now and then determine if it will handle the new power converter. If it does not, you need to get a larger AWG wire with the correct temperature class of insulation, which may fit OK in the larger lug on top of the bus bar. Again, the new wire needs to be OK to work with the larger lug.

If this comes out that the large lug rating will still not clamp on your new wire, then put the DC negative wire under one of the green lugs on the bar.

Does this make sense to you now?

Hope this helps.

Johh

[CampingProf]

Extremely helpful (as always)! Here's a few pictures of the upgraded bus bar and finished electrical upgrade.







I bought the 35 Amp model so I wouldn't have to worry about being too high powered for any of the existing wiring. Was that a safe bet?

I've got two outstanding issues:
One, when I'm near the converter (while plugged in) there's a quiet, high pitched sound. I can put it into storage mode (low trickle charge) and it goes away. And I can't really hear it if I'm not near the converter. Is that normal? Should I just live with it? Or is that a cause for concern? (I had to replace one of the same model already because of a very loud highpitch noise. I'm told that noise was a sign of a failing capacitor. But I really don't want to install this whole system a third time).

Two, I installed a new USB port and ceiling fan on the DC side. And both work great. I also installed a propane detector the exact same way... and it just doesn't work at all. Any idea where I should start trouble shooting?

Thanks John for all your help. I literally couldn't have done this without you. Working the old bus bar up the ground wire and then the new one back down was a pain in the butt, but I'm glad I did that rather than cutting it.

Cheers!

[JohnB]

Your handy work looks great! . Good job.

And thanks for the good words; I'm always glad to help.

The DC negative white wire size with the insulation rating Sunline used, should be OK with your new converter.

The converter noise, h'mm, the noise you are reporting, I have not run into with the Progressive Dynamics converters. I have been using them since 2008 and have not heard of that issue. In our T310SR camper, we camp in all the time; I have the deck mount 9260. https://www.sunlineclub.com/forums/f...rade-8888.html

I have installed several 4600 series in friends' campers as they are a drop-in for the WFCO brand when they go bad. All of my changeouts have been 55 amp or 60 amp, The 9600 or 4600 series. I wonder if the amp ratings matter. I have not camped in the 4600 one I replaced, but I do not recall a high-pitched noise during testing. They hardly make any noise. But again, these were all 55-60 amp ones, so they were not generating near full capacity. Did you get a chance to call PD directly and ask?

To this

I also installed a propane detector the exact same way... and it just doesn't work at all. Any idea where I should start trouble shooting?

Well, OK, what brand and model propane detector? I would start with a volt meter test on the + & - wire where you connect the LP detector. On DC circuits, if the ground wire (negative) is not getting a good connection, the hot wire can be fine, and the circuit will not work. If you have no voltage at the hookup connection, then test the hot wire to a lengthy test wire back to the DC negative to confirm you have power on the hot wire. If the hot wire is good, then do an ohm test for continuity on the LP negative wire with your long DC negative test wire. If there was no power, one of them have an issue.

If you have power to the LP detector, ensure the detector is wired on the correct polarity. If that comes up good to its wiring diagram, you may have a dud. Again what brand/model?

Hope this helps

John

[Tinstaafl]

I'd be interested in a definition of "quiet, high pitched sound" before hazarding a guess whether it's a cause for concern. A lot of electrical/electronic devices do emit sounds caused by minute vibration of the components (most often transformers), usually louder when the load is heavier. The vibration is caused by fluctuating magnetic fields.

Switching power supplies are fairly notorious for that, but I have no idea whether your converter uses one. Older converters never did, but who knows these days?

Normally it's not much of a concern unless it's just too obnoxious to tolerate. Agree with John; probably best to contact the manufacturer and see what they have to say about it.

[JohnB]

Hi CampingProf,

I just saw something in your excellent pic here. . We can clearly see what you have when we zoom in.



On the top left-hand side between the 3rd and 4th screw counting up from the bottom of the AC neutral bus bar (the one with the solid white wires on it), there is a bare solid earth-ground wire that is very close to the buss bar. That bare wire may not be touching the buss bar now, but bouncing down the road towing, it may get more nudged towards the bar and touch. If it does touch the buss bar, when you plug in the shore power, it will trip any working GFIC outlet.

Consider moving that one bare wire more to the right, like the other bare earth-ground wires, to get more separation.

John