Looking for a builder

Interesting topic this one, and something I've been thinking about for my static caravan setup recently.

The challenge with finding someone competent to design and install a proper low-voltage off-grid system in the UK is that the pool of qualified people is surprisingly shallow. Most electricians I've spoken to locally either glaze over the moment you mention Victron kit, or they quote you for a full domestic rewire when all you need is a 12V DC system with a Cerbo GX for monitoring.

For anyone else in a similar position, my experience has been that the best builders for this sort of work tend to come from the narrowboat or motorhome conversion world rather than traditional electrical contracting. They understand battery management, MPPT charge controllers, and bus bar sizing in a way that your average spark simply doesn't.

A few things worth specifying clearly when approaching anyone:

• Full Victron ecosystem — MPPT, Cerbo GX, Venus OS, BMV shunt. Non-negotiable for proper monitoring.
• Battery chemistry knowledge — whether you're running Fogstar Drift LiFePO4 or AGM, they need to understand charge profiles.
• Load calculations done properly — not back-of-envelope stuff.

For a community or multi-use building (I've seen similar projects for scout huts and sports clubs up here), the 12V approach starts to strain at scale. You might want to have a serious conversation about whether 48V and an inverter-charger makes more practical sense once your load profile grows.

Has anyone here actually commissioned a larger community-scale build in the UK? Curious whether there are decent installers people would genuinely recommend.

Narrowboat install taught me a lot about this. Finding someone who actually understands DC systems rather than just slapping solar panels on and calling it a day is genuinely hard.

Worth checking if they're familiar with Victron kit specifically — it's become something of an industry standard now, and if they can't talk fluently about MPPT settings or battery comms they're probably not the right person.

A few things I'd ask any potential installer:

• Can they show previous off-grid work (not just domestic solar)?
• Do they understand battery chemistry differences (LiFePO4 vs AGM)?
• Are they comfortable with BMS integration?

The NAPIT/MCS route doesn't really cover low-voltage DC properly, so certifications aren't a reliable filter. Word of mouth from communities like this is probably your best bet honestly.

Really interesting thread this one. Does anyone know if there's a recognised qualification specifically for off-grid DC systems in the UK? I'm asking because when I was sourcing quotes for my shepherd's hut build, I found plenty of solar installers with MCS certification but they were very much geared towards grid-tied domestic installs — the moment I mentioned battery storage and Victron kit they seemed less confident.

@MuddyFisher makes a good point about DC knowledge being a different skill set entirely. I ended up learning a huge amount myself through forums like this one, but ideally I'd want a professional to sign things off properly.

Would a marine electrician potentially be worth approaching for narrowboat or off-grid work? Presumably they're dealing with 12/24V DC systems day-in, day-out?

@CamperClive — there's no single dedicated qualification, but look for ECS Gold Card holders with a DC bias, or anyone certified under the IET Code of Practice for Low Voltage Direct Current Electrical Installations. That document is genuinely the bible for this stuff.

@MuddyFisher is right that marine electricians often understand DC systems better than domestic sparkies — the RYA/MCA commercial endorsement crowd especially.

For my static caravan setup I ended up going with someone who primarily does narrowboat and motorhome conversions. He understood battery chemistry, proper cable sizing for volt-drop at 12V, and why my Victron MPPT and BMV-712 needed to talk to each other properly. A domestic electrician would have been lost.

Ask candidates specifically about volt-drop calculations and fuse sizing at source — if they hesitate, walk away.

Good points all round. I'd add that the MCS installer database is worth a look even if you're not going for a grid-tied system — some of those installers have solid off-grid experience and at least you've got a degree of accountability if things go wrong.

Word of mouth remains king though, honestly. @CrafterWanderer, I'd suggest posting in some of the static caravan and park home Facebook groups — there are a surprising number of people who've had decent installs done and are happy to recommend someone local to them.

Also worth asking any installer for photos of previous work and, crucially, their cable sizing calculations. Someone who can't show you their working is someone I'd be wary of regardless of what cards they carry.

@VanIan good shout on MCS — though half of them take one look at a caravan and suddenly remember a prior engagement 😄

Seriously though, my actual tip: ask them what battery chemistry they prefer and why. If they say "whatever's cheapest" without any follow-up, walk away. If they launch into a 20-minute