Campervan Electrical Build Checklist: Before You Power Up

Before inserting your main fuse and powering up the van electrical system for the first time, work through this checklist. It is much easier to find problems before the system is live than after.

Pre-power checks — 12V system

Battery and main cables

Battery is secured and cannot move in any direction
Battery terminal covers are in place or removable covers available
Main positive cable runs from battery positive → ANL fuse holder → positive bus bar
ANL fuse holder is mounted within 300mm of battery positive terminal
ANL fuse is NOT yet inserted (leave out until all other checks complete)
Main negative cable runs from battery negative → shunt (if fitted) → negative bus bar
Negative bus bar (or battery negative) has a chassis earth connection at a clean bare-metal point
All cable terminations are crimped (not soldered alone) and covered with heat shrink

All positive cable runs

Each circuit cable is fused within 300mm of the bus bar / positive source
No unfused lengths of positive cable are accessible that could short against the chassis
All cables are routed away from sharp metal edges — protected with grommets at all panel penetrations
No cables are pinched by moving parts (seats, bed slats, sliding doors)
All cables are clipped or secured every 300–500mm

Inverter (if fitted)

Inverter has its own dedicated ANL fuse within 300mm of bus bar/battery positive
Inverter DC cable is correctly sized for inverter rating
Inverter is mounted with ventilation clearance on all sides
Inverter remote switch (if used) is connected to remote port, not to DC input

DC-DC charger (if fitted)

Input positive fused within 300mm of starter battery positive
Output positive fused within 300mm of leisure battery positive (or bus bar)
Ignition sense wire connected to a switched 12V live source
Input and output negative connections confirmed (chassis earth, not direct battery negative at the battery)

Solar charge controller

Panel array is not connected to the controller yet (connect panels last to avoid controller damage)
Controller to battery cable is fused and correct size for MPPT output current
Controller is mounted with airflow available

Pre-power checks — 230V system (if fitted)

Shore power inlet and wiring

CEE17 inlet socket is watertight and correct rating (16A minimum)
Inlet is protected by an RCD (30mA) immediately after inlet
RCD is double-pole (disconnects both live and neutral)
Consumer unit MCBs rated correctly for each 230V circuit
All 230V wiring is 2.5mm² minimum, correct 3-core cable (brown/blue/green-yellow)
Inverter output connected to RCD input (not direct to sockets)

Earth and neutral-earth bond

Inverter AC earth terminal connected to van chassis
Neutral-earth bond confirmed (at inverter or consumer unit — check inverter datasheet)
No 230V circuit connected to chassis other than the earth terminal

RCD test (after power-up)

RCD TEST button pressed — RCD trips. Reset.
RCD RESET successfully restores power
All 230V sockets have the correct polarity (plug a socket tester — all lights green)

Commissioning sequence

Once pre-checks are complete:

Connect solar panels to MPPT controller (panels pointing away from sun if possible during initial connection)
Insert main ANL fuse — battery is now live
Check all bus bars for correct voltage
Switch on each circuit individually and verify it works
Start engine — verify DC-DC charger begins charging (check indicator or app)
Connect to hook-up (if available) — verify mains charger starts, RCD test passes

Ongoing checks (annually)

Inspect all cable terminations for corrosion or heat damage
Check all ANL fuses — no signs of oxidation on contacts
Test RCD
Check battery state of health (full charge, load test, BMS status check)
Inspect chassis earth connections — remove and clean if any rust or paint has migrated under the lug

FAQ

Do I need an electrician to certify my campervan electrics?

The 12V DC system in a campervan does not require certification. The 230V system is not subject to Part P building regulations (campervans are vehicles, not buildings). However, having the 230V system inspected by a qualified electrician is strongly recommended for insurance and resale purposes.

Should I do any insulation resistance testing?

A qualified electrician would use an insulation resistance tester (Megger) to verify no conductors are touching the chassis or each other. As a DIY builder, visually inspect every cable run for damage and test each circuit's function. If in doubt, have a professional check.

Can I commission the system with the leisure battery not fully charged?

Yes — you do not need a full charge to commission. Most check items only require battery voltage to be present. Check functionality with battery at any reasonable charge level (above 12.0V).