Doing electrical work after insulation

Hi there! New to the forum and we just purchased a Promaster LWB extended w/ a high roof.

We’re wondering about doing this build in parts. We don’t have the budget to do everything at once, so we’re starting with the bed frame, flooring, insulation and fan. (Probably starting out with a Yeti 400 to power the fan as needed.)

Eventually we want to mount solar panels to the roof and wondering what is the best way to “prep” the van for that step in the process. We want to insulate but also leave enough space in the roof to drill holes later on the thread our wiring through. In other words, we want to get the van ready for staging this part of the build, but we don’t have our batteries and solar panels quite yet…perhaps in a couple months.

Does anyone have any recommendations and/or diagrams for this step in the process?

We don’t want to set ourselves up for failure down the road because we essentially enclosed the whole van in insulation and forgot to leave room for drilling holes in our roof.

Any tips/pictures/anecdotes are appreciated!


We have done ours so far in this order: Windows and Vent, Floor with insulation, Rest of Insulation, Bed, Electric (lights and vent), Walls/Ceilings, Panels over doors areas. I wish we had done the bed first though.

For Solar we have enough room to still go through the roof as you can’t really take the walls 100% back. I guess you could but I wanted ours to end up square. We have not trimmed that in yet so we have room to tuck that wire in. I am pretty confident this will be the only hole we are going to drill in the roof for wiring if we ever do it. We honestly haven’t had a need for solar as of yet so we might just get one of the briefcase deals that we can fold out when we need too.

For the price of the Yeti 400, you could have a battery, battery isolator, fuse panel and the breakers, for probably cheaper if not half of the price.

I think you will want to at least run wires for your lights and fan before you close the walls in. I’m Not sure about the insulation you are using, but I can tell you wool is not something you want to attempt to drill, saw or spin anything through. The more rigid foam may be ok with cutting through afterwards.

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Thanks Bretly. We have a prodeal for Goal Zero, but yes, it may be more cost effective to go ahead and buy what you had listed above.

Greetings & Welcome!

Every other power option should be implemented before solar, and if done properly solar is an expensive and unneeded option.

My entire house power system cost under $100 installed. House battery, isolator, wiring, the whole works at a battery recycler. Then I switched my starter battery to also be a deep cycle battery and added low battery cutoffs to each battery. With this setup I can go two full weeks, one week off each battery, and still have plenty of power to start my rig. I added an el cheapo $100 inverter generator to the mix along with a $29 battery charger, to insure I would never be without power.

My van has no wiring per se. I put my house battery in a marine style plastic battery box, and added 4 fused accessory ports to each side, for a total of 8 accessory ports. My house battery is behind my drivers seat, and plugged into one of the ports is a 15 foot extension cable with an additional 4 accessory outlets ran to the back of the van. Simple, cheap, easy, and extremely convenient. No hidden wires to ever cause troubles. The extension just runs along the floor behind my cabinets.

Goal Zero, Yeti, etc; are very expensive for what you get. It’s cheaper up front, and long term to do it right the first time. Each component in my system is easily replaceable anywhere, and that feature alone is priceless. Spending days or weeks fixing stuff is for the birds.


"If you prepare for the worst, every thing else is easier." ~ Off Grid

I would not make a hole in the roof. Instead I’d route a hose/tube along the passenger side A-pillar and draw all the cables (to panels and lights in the future) thru that. A black tube, thinner than a pinky finger. Nobody will see it when it goes along the window seal.

Once it goes under the bonnet, find a way to get wire to the charge controller. Also once you are under the bonnet, wire another one from alternator/main battery to the charge controller so you’ll charge batteries while driving.

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We decided to insulate before wiring. Our floor plan will allow us to run all wiring through the built-in structures. Even the fan wiring will be going from the Garage, through the seating, up the storage tower, then into the Drop ceiling. I think this will make us happy in the future when upgrades/repairs are made.

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