12 Volt & Plywood
Numbers you can
actually cut to
Reference material for wiring and cabinetry in vans, RVs, boats and off‑grid spaces. Everything in both unit systems, and where the two systems describe genuinely different products, we say so instead of converting.
Tools
The two-unit problem
Most sites that publish build numbers pick one unit system and convert. That works for a length and fails badly for a material, because a sheet of plywood and a length of cable are sold to different standards in different countries. These are not the same object with two labels.
| Sheet | Metric | Imperial | Where |
|---|---|---|---|
| us-4x8 | 1220 × 2440 mm | 4 ft × 8 ft | US, CA, UK |
| eu-2500x1250 | 1250 × 2500 mm | metric only | EU |
| au-2400x1200 | 1200 × 2400 mm | metric only | AU, NZ |
| baltic-birch-5x5 | 1525 × 1525 mm | 5 ft × 5 ft | US, CA, UK, EU, AU |
The European sheet is 60 mm longer and 30 mm wider than the British one. Baltic birch is square. A cut list nested for a 4 × 8 sheet can be physically unbuildable on Australian stock, because the long side is 40 mm short.
| Called | Actually | Never swap with |
|---|---|---|
| 3/4 in | 18.26 mm | 18 mm |
| 18 mm | 18 mm | 3/4 in |
| 1/2 in | 11.91 mm | 12 mm |
| 12 mm | 12 mm | 1/2 in |
| 3/8 in | 9.13 mm | 9 mm |
| 9 mm | 9 mm | 3/8 in |
| 15 mm | 15 mm | — |
A US sheet sold as three quarters of an inch measures 18.26 mm. A metric 18 mm sheet measures 18 mm. Cut a groove for one and fit the other, and the joint rattles.
The full tables are on the reference page, including the four AWG sizes where the nearest metric cable is smaller rather than larger.
Guides
Renovation rather than conversion. The vehicle already has an inside, and most of what is wrong with it is factory cabinetry built light and cheap. Every guide cites its sources.
Painting RV cabinets
RV cabinets are thin film over soft core, not solid wood, so the usual kitchen-cabinet advice peels. What to do instead, and why primer matters more than paint.
Replacing RV cabinet doors
How to measure overlay, pick hinges that survive a road, and decide between ordering doors and making them. The carcasses are usually fine; it is the doors that fail.
RV flooring
Why floating vinyl plank is usually right in a vehicle, where gluing it down is a mistake, the one place you should glue anyway, and what to check underneath first.
Camper renovation, where to start
Find the water before you spend anything on the interior. A sequence for inspecting a camper properly, and the order to do the work in so you are not undoing it later.
RV storage that stays put
Household storage assumes the room stays still. Latches that actually hold, filling voids so nothing shifts, and why where you put the weight matters more than how much you fit.
Pop-up camper remodel
A pop-up has two budgets: what the lift system will raise, and what the trailer is rated to carry. Where the weight can go, what to check first, and the order to work in.
Old camper remodel
An old camper is two projects: the remodel you can see, and the parts that age out even in dry storage. Rust, tires, wiring and propane gear, in the order to tackle them.
Truck camper remodel
A truck camper remodel is decided by one number on your truck, not by the camper. Payload, center of gravity, tie-downs and the 12 volt side, in the order to tackle them.
RV renovation costs
Most of the spread in RV renovation costs is the condition of the vehicle, not the finishes. Sourced ranges for water damage, roof, paint, flooring and 12 volt, and where the money goes.
Why you should believe any of this
Fair question, and the answer is not "trust me". Every figure here is either produced by a formula written out on the page where it is used, or it is a fact taken from a named source that is linked so you can check it. The calculators show their working, including the assumptions, and each one has a section saying what it deliberately will not answer.
There are no advertisements, no affiliate links and no sponsored posts. Nothing here is a substitute for a qualified electrician or for your local wiring rules, and the site says so on the pages where it matters rather than only in the footer.