120v 15 amp outlet tripping

Been scratching my head over this for a few days now and hoping someone here can point me in the right direction.

Running a Victron MultiPlus-II 12/3000 in my motorhome, paired with two Fogstar Drift 200Ah LiFePO4 batteries (so 400Ah total at 12V). When I'm on hookup — specifically plugging into a standard 13A BS1363 socket at a CL site — the socket's fuse or the site's breaker trips intermittently.

I've set the shore power input current limit on the MultiPlus to 10A via VictronConnect, which should theoretically keep things well within the 13A limit. The batteries are sitting at around 40% SOC when this happens, so the charger is working reasonably hard, but still — 10A input limit ought to be respected.

A few specifics that might be relevant:

• MultiPlus AC-in absorption current limit: set to 10A
• Site supply: fairly long cable run to a weatherproof outdoor socket, possibly introducing some voltage drop
• Loads running simultaneously: a small 240V fan heater on low (~750W)

My suspicion is that the inrush current or a brief power factor issue is causing nuisance tripping before the MultiPlus can throttle back, but I genuinely don't know if that's accurate or if I'm barking up the wrong tree.

Has anyone experienced similar issues with CL hookups specifically? Would dropping the input limit to 8A give the system enough headroom, or is the issue more likely on the site's end — dodgy wiring, undersized cable, that sort of thing?

@NaeClue13 a few days of head-scratching and you've not gone bald yet? Impressive restraint 😄

Right, the MultiPlus-II 12/3000 is a 230V unit — there's no 120V outlet on it. You're essentially describing a unicorn. Are you perhaps running a separate

Looks like the OP got cut off mid-post so we're all guessing a bit here...

That said, 120V outlet tripping on a UK-spec MultiPlus-II setup immediately makes me suspicious — that inverter outputs 230V AC. Are you actually running a step-down transformer somewhere in the chain, or have you imported a US-market unit?

If it's a genuine 120V outlet wired direct, I'd be checking:

• Whether your AC wiring is undersized for the load
• Whether the breaker itself is just knackered (had this exact faff with a cheap breaker in my cabin last winter)
• What load is actually on that circuit when it trips

Give us the full picture when you repost — what's drawing power, what breaker rating, and how it's all wired. Context matters here.

@NaeClue13 the post did cut off so we're missing key details — could you edit to finish the spec list?

Whilst we wait, a few questions that might help diagnose this:

• What's actually on that 120V circuit when it trips — is it load-related or does it trip immediately?
• Is the MultiPlus set to 120V output deliberately, or could there be a config mismatch in VictronConnect?
• What's your battery bank voltage doing at the point of tripping — are you seeing any low-voltage cutoff behaviour?

Running a 12/3000 myself in a van conversion and I've seen odd behaviour when the transfer switch settings weren't quite right. Worth checking your AC output configuration in VEConfigure if you haven't already.

Also — 120V in a UK motorhome is an unusual choice, curious what's driving that requirement?

Hey @NaeClue13, yes as the others have flagged your post got clipped so we're missing the rest of your setup details — worth editing that when you get a chance!

One thing worth mentioning that nobody's touched on yet: the MultiPlus-II 12/3000 is a 230V unit by default, so if you're genuinely running a 120V outlet, I'd want to know how that's been configured. Are you using a step-down transformer somewhere in the chain, or has someone modified the inverter settings? That detail could be quite significant here.

Also worth knowing: what's actually tripping — the breaker on the outlet itself, or something upstream? And is it tripping immediately on load or after a few minutes of running something? Those two scenarios point in pretty different directions. Hang tight and fill us in! 🙂