6x12 cargo trailer conversion for camping.

[rebelrider.mike]

New video:

Just me talking again. This time I'm giving a brief overview of how I plan to do the electrical. I've updated my wiring diagram too, based on some new stuff I've learned lately about my battery and solar panels in general.


I've been thinking about grounding lately. Specifically, what to do with the ground wires that lead up to my isolation switch, and the ground post on the body of the inverter. I've made a diagram showing much more detail of the AC side of things to maybe help me figure it out.



So here's what I think I know:

-If the trailer is connected to a service connection somewhere, there should be a physical ground rod buried in the actual dirt somewhere.

-If the trailer is connected to a generator, there should be a bond between the ground and neutral. Either inside the generator or via an adapter.

-If the trailer is connected to nothing, there will be no ground connection to either neutral or earth.

-The neutral bus bar in the breaker panel needs to be isolated from ground.

-The trailer body needs to be connected to ground.



Here's what I'm not sure of:

-The solar panel frames (being aluminum) and mounting hardware should be grounded to the trailer body?

-The solar panel frames should also be grounded to the inverter via the ground connector on the inverter's body?

-The inverter body should be grounded to it's AC output ground?

-All the ground wires meeting up at the isolation switch should be connected together?



Vaguely related: I plan to use GFCI breakers, or maybe the GFCI/AFCI combo breakers.



Anyway, does it mater that sometimes the trailer will be connected to a ground rod, and sometimes just boded to neutral, and sometimes neither?

[rebelrider.mike]

Well, I've done more digging around, and I still think that what I know is correct. As for the things I'm not sure of, it's looking like the solar panel frames and any mounting hardware should indeed be grounded to the trailer body. What's more, a lot of aluminum products are anodized, which causes high resistance, so any ground points should be connected to actual bare aluminum. It looks like the ground lug on the inverter body should also be grounded to the trailer body. And from what I've seen, all the ground wires meeting up at the transfer switch should be connected.

I guess there's some inverters that bond the neutral to ground on the AC output side to simulate a path to ground. Some appliances and electronics won't work if they detect an open ground. I think this is what my inverter does. So in my case, I definitely need to have both the hot and neutral wires isolated at the transfer switch. This will prevent having more than one neutral/ground bond in the system at a time.

I've also just learned that there is supposed to be a bond between the AC ground and the DC negative. But only one. When the trailer is hooked up to the truck, The AC ground will be bonded to the truck's negative through the chassis. But that goes away when it's unhitched. My battery is a different voltage than the truck's, so I've been planning on keeping the DC isolated from the AC. Not sure now if that is still the best way to go or not.

[Mike90250]

Aluminum should not be counted on for any electrical capacity, unless it's tin plated. It oxidizes instantly, and the oxide layer is a super tough insulator. (aluminum oxide sandpaper). Look into tin plated copper braid, or route some bare #2 wire as your ground.

[rebelrider.mike]

I'll have to work out the details once I actually start to build the thing. In the meantime, here's an updated diagram based on what I've learned so far:
2618b947f7f177478b57a85a19f7aa11.jpg
I think that's going to be all for my grounding research. In other news, I got my solar panels! I made a short video of my solar plan and unboxing and testing a few of the panels.

This weekend is the last cargo run before the trailer gets gutted and rebuilt. From there, progress will only be limited by funding, weather, and how much energy I have between this and other projects.

[nomadh]

Well, I've done more digging around, and I still think that what I know is correct. As for the things I'm not sure of, it's looking like the solar panel frames and any mounting hardware should indeed be grounded to the trailer body. What's more, a lot of aluminum products are anodized, which causes high resistance, so any ground points should be connected to actual bare aluminum. It looks like the ground lug on the inverter body should also be grounded to the trailer body. And from what I've seen, all the ground wires meeting up at the transfer switch should be connected.

I guess there's some inverters that bond the neutral to ground on the AC output side to simulate a path to ground. Some appliances and electronics won't work if they detect an open ground. I think this is what my inverter does. So in my case, I definitely need to have both the hot and neutral wires isolated at the transfer switch. This will prevent having more than one neutral/ground bond in the system at a time.

I've also just learned that there is supposed to be a bond between the AC ground and the DC negative. But only one. When the trailer is hooked up to the truck, The AC ground will be bonded to the truck's negative through the chassis. But that goes away when it's unhitched. My battery is a different voltage than the truck's, so I've been planning on keeping the DC isolated from the AC. Not sure now if that is still the best way to go or not.

Don't know what's best practices on your system but the 1 thing I needed to do before my home system was certified was to unbolt 1 clamp from every paned and file the anodizing off the panel contact pt and the clamp face to ground every panel. He made me promise to do it and he'd sign me off. So I did it.
I think I did it.
I know I meant to.
I hope I did it

[solaarone]

I don't know if it's too late, but I made a 6x12' conversion like this back in the 90's. We didn't use solar, just some oil lamps. Basically it had a sleeping platform, a couple windows, a gravity shower, and a bunch of storage shelves.

What I did find out is to make a 5" layer (your panels?) on the roof that can lower the cabin temp by 20F. I put a thick silver tarp on top of bolts sticking through the roof into the eyelets, giving about a 5" airspace between the roof and the tarp. Next, I tied-down the edges with bungees. Then I put four screened 6x14"(?) vents in the floor, next to the walls, and matched them in the roof. A lot like your average tent, the tarp protects from the rain.

I kept the vents open during the day, then closed during a cold night. I duct taped the roof vents during traveling if it rained. Sold the thing before working out a better fix, I would probably have made a inner tube cover and dzus fasteners. I'm sure they make flaps of some sort these days. Have fun!

[rebelrider.mike]

Here it is July, and it's still raining where I live. But I did get a box built for my battery.

We're still cleaning out the carport so I have room to empty out the trailer. Can't really work on it until it's empty. I'm hoping this week I'll be able to start moving things.

[rebelrider.mike]

Finally got the trailer cleared out! Now I can start dismantling the inside.