6x12 RC Workshop/Cargo Trailer Build

[orcadigital]

No picture updates, but have all of the outlets on the left wall installed, and roughing in the wiring. Need to get some different grommets for the holes between the side walls and the upper curve where the wiring runs.

I have spent some time reading about grounding and different thoughts on trailers. The existing wiring for the exterior running lights (brakes, signals, etc) all grounds to the frame. I plan on running the grounding bar in the WFCO out to the frame as well for the AC power. I also bought another grounding bar to run for the DC negative side. I will be running dual wires to all of the DC lights, and grounding through the bar to the frame in one place. All that being said, is there any issues with grounding 2 different DC systems and 1 AC system all to the same frame? Do I need to disconnect the TV (wiring or everything) when plugging in shore power as a safety measure? In general, all of the topics on this seem to get overly technical without answering the basic question of it being ok to ground the AC and DC system through the frame together. The wrinkle (possibly) is that I will not have a battery initially (if ever) and so I obviously cannot take the negative of the DC side back to the negative on the battery. The WFCO appears to take the negative on the DC side to the ground on the AC side, which makes me think I need to ground the DC wiring back to the AC ground (frame in this case).

Any ideas would be awesome.

Thanks!

[OverTheTopCargoTrailer]

You need to pray to BRUCE - he is the electric GOD on this forum.

BRUCE ...... HELP WE NEED YOU HERE !!


I'm only a newbie with 2100 watts solar .....
All my ac junk is grounded back to a single point Ground bus , Where it would attach to a ground rod next if I had one.
My dc all goes to the battery negative & panels go to ground bus.

elec panel.JPG (103.73 KiB) Viewed 2014 times

found a better picture

DSCN9185.jpg (62.07 KiB) Viewed 2011 times

from the outside

DSCN9184.jpg (51.77 KiB) Viewed 2010 times

Damn I see a loose wire or 2 or 3 in my cabinet,
NOW I will need to visit Bruce for sure before i energize my Lasers

Double damn - on the bottom right are my 2 ground bus bars - I better install them

[orcadigital]

So does the battery negative ever get grounded to the chassis on yours?

On some of the other threads, people kept saying that they do not ground the DC, and run double wires to each device, but the negative wires still seem to collect back to a central point which seems to eventually get connected to the frame.

The negative terminal on the DC side of the WFCO is connected currently to a wire coming out of the convertor part of the box (that converts from AC to DC). That is a shared point that a battery negative would come back to. The positive from the convertor also connects to the DC panel, but has a separate connector for the battery positive connection (I assume due to the charging circuit). As the AC>DC convertor grounds to the grounding bar inside the unit (on the AC side), which is supposed to be grounded back to the frame, I assume that the logical method would be to take the DC ground (on the DC side of the convertor) also back to the frame.

Attached is the wiring diagram. You can see the "to DC branch circuits" on the right, but there is no "from" or negative side and that is what leads to my confusion.

[OverTheTopCargoTrailer]

Personally I do all my DC with 2 wires from the battery.

I only run an dc equipment ground back to a main elec bus bar I installed on the trailer exterior.
I don't like to ground JACK to the frame as there is corrosion & rust that can develop.
I like to run single wires and tap - splice from those, so only one light not 10 go out.

Generally my understanding is just to have a single ground location for both ac & DC.


But Bruce is the main Electric God on the Forum

Jerry

[AZ_Desert_Rat]

I agree with Earnest -- Any PROGRESS is great!! I am continuing to watch to see if I can pick up any ideas from your build!

[MtnDon]

It is preferable, for reliability, to use two wires to any DC device.

[orcadigital]

So still a bit confused on the DC wiring. I am running 2 wires to everything, that was never in question. The question is what the negative wire connects back to. I do not have a battery, so do I connect the negatives to a grounding bar and then to the frame or grounding bar and to the negative battery terminal connection on the WFCO?

I did make some progress this weekend. In general, it sure does not seem like a lot when I describe it, but it involved a lot of hours of work. I finished up the wiring on the left side, installed the insulation and the plywood. Wired in the new fender lights, and installed the inside outlet on the right side and outside outlet on the same side. I also temporarily installed 2 of the 4 LED light bars for general lighting. They are dimmer then I was expecting, but I think for the .4W they pull each and to be able to see when packing up, it should be plenty. Sure does not sound like much progress for about 12 hours of work over 2 days... Anyway, pictures included.

I have been following the insulation thread as well, and as this is a light use, low budget build, I am content with what I am doing. I understand it is R3 and there are many many places where the air is flowing past. This is to help in whatever marginal way it does with air conditioning and sound deadening. The walls also feel sturdier with something filling the gap between the inner plywood and outer sheet metal.

[MtnDon]

I do not have a battery, so do I connect the negatives to a grounding bar and then to the frame or grounding bar and to the negative battery terminal connection on the WFCO?

I would connect the negatives all to a common point; a buss bar. Then a connection from there to the power source.
Sort of ditto on the positives, except they would go to a fuse or breaker for however many circuits you would divide things into and then positive lead to the power source.

Hope that helps.

[Rainier70]

I used a BlueSea Fuse Box with ground bar for my DC circuits.

http://www.amazon.com/s/ref=nb_sb_ss_sc ... fuse%20box

[orcadigital]

I do not have a battery, so do I connect the negatives to a grounding bar and then to the frame or grounding bar and to the negative battery terminal connection on the WFCO?

I would connect the negatives all to a common point; a buss bar. Then a connection from there to the power source.
Sort of ditto on the positives, except they would go to a fuse or breaker for however many circuits you would divide things into and then positive lead to the power source.

Hope that helps.

I posted an image of the wiring diagram of the WFCO unit a few posts back. It has the fused outputs on the DC side, and will be running a couple of those out to a switch panel I picked up. The positives all go out from the convertor (master fuses coming in for reverse polarity protection @ 40A) and then individually fused at 15A or 20A depending on the channel. There are larger connection points for the positive and negative battery terminals (which currently have wire going to them for the charging circuit, and a spot on each for wiring to the battery), and a +VCC which has power supplying the DC board. A battery would connect to the positive and negative, and the assumption is I would connect the negatives into that negative line (through a grounding bar/buss and a wire from there to the negative terminal). It sounds like I should run everything back to that negative battery terminal connection. The outstanding question would be if I ever add a battery, do I run the wires directly to the convertor, or ground the battery negative also. Question for a later date though.

At this point, will be using 2 DC circuits going to 1 switch panel (with 4 switches), 1 circuit for the outside light, another for the inside LED's, which will go to 3 of the switches. I will run wiring for the 2x 20A circuits, that I will use later for powering DC chargers for the RC car batteries.

Thank you for all the help!

[MtnDon]

The outstanding question would be if I ever add a battery, do I run the wires directly to the convertor, or ground the battery negative also. Question for a later date though.

Thank you for all the help!

If you add a battery to the system at some point I believe it helps the thought process to divide the system up into components.

A battery should have a disconnect switch, something like this... It should also have a fuse like a class T fuse, which is a very fast blow type, to protect against any catastrophic dead short. The fuse would be between the switch and the battery. Let's call the switch terminal that connects to the battery or battery fuse Terminal B.

The converter DC output positive would then connect to the other terminal of the master switch, call that Terminal C.

The positive wire that would then carry current to the fuse box input would also connect to Terminal C.

That's one way to do it.

Hope that helps

[orcadigital]

Some weekend updates.

• Built out the cabinet that is not a cabinet on the left side, including a shelf to hold the convertor box
• Leveled the top of it to be the same as the cabinet on the right
• Installed a horizontal board under the upper cabinets to support the backsplash
• Installed 2 gang boxes and wired in the outlets including 2 GFCI’s (one for the left, one for the right circuit) and a specialty outlet with 2 USB ports
• Roughed in a DC circuit to the left side of the trailer for future use.
• Roughed in the remaining DC for the lights
• Finished the clamping wire control on the left side of the trailer
• Installed the left upper cabinet, leveled both and centered off the lower cabinet
• Built in left and right side trim to fill in the gaps and give a surface to mount the sides of the backsplash
• Test fit the counter
• Wired all of the AC into the convertor box
• Tested all AC outlets – All working as intended including the outside outlet, powered through the 30A main shore power inlet on the front of the trailer

Biggest win, and my goal for the weekend was getting the AC wiring finished and tested. All of the outlets work and GFCI's work without a hitch. Sadly it took until 5pm Sunday before I even got to start wiring the converter, as I had not realized everything that had to be done in the front before I could start that bit of process. All went off without a hitch, minus forgetting to hook up one hot line to the circuit breaker on the first go round. At least it is beginning to take some shape.

Still on the list to do is wire in all of the DC (wire is there, but need to connect everything), finish the insullation on the right, plywood on the right, mount the right side interior lights, RV door handle, all of the ceiling, all of the flooring, and then mount the etrack, build the counters and air conditioner mount.

[Rainier70]

Very nice! It is moving along quickly.

[hankaye]

orcadigital, Howdy;

Nice job ... Looks like you have a plan and it's workin' for ya... ,

hank

[orcadigital]

I definitely could have planned it out better, but getting the power working was a big step for me. Other then some switch/dimmer replacements in my house, AC wiring is all foreign to me. The DC wiring is next, and I am still dreading the RV door handle as there seems to be a fair bit of cutting and precision to getting it just right.

I appreciate all the help here and in all the various threads. Allowed me to skip many of the pitfalls everyone else documented from their builds.

Thanks!

Grant