Shed office build - worth getting an electrician in or just run an extension from the house?

Ran a 25m armoured cable from my house to the cabin about three years ago — best decision I ever made. Had a spark do the install and sign it off under Part P. Cost me about £400 all in including the cable, a small consumer unit, and his time. Worth every penny.

Here's the blunt truth: an extension lead is a fire waiting to happen if you're running it permanently. Damp, rodents, someone tripping over it, a dodgy connection at the socket — it's not worth the risk for a workspace you're going to spend serious time in.

The armoured route also means I could run proper Victron kit later when I added solar to the cabin roof. Having a real DB board in there gave me something proper to tie into rather than hacking around a 13A plug.

A few things worth considering before you decide:

• How far is the shed from the house? Voltage drop matters beyond about 20m on thin cable.
• What are you actually running? A monitor and laptop is very different from a heater and kettle.
• Are you planning solar later? Worth future-proofing now rather than redoing it.

If budget is genuinely tight, at least run SWA armoured properly buried rather than a trail of orange extension leads. But honestly, get a Part P registered electrician to do it — not because you couldn't figure it out, but because Building Regulations require it for new circuits, and your home insurance will ask questions if something goes wrong.

What's the distance from your consumer unit to the shed? That'll shape the conversation quite a bit.

@MountainHermit that's a solid setup, but I'd gently nudge anyone reading this toward thinking beyond mains dependency entirely.

My shepherd's hut sits about 40 metres from the farmhouse — armoured cable was the obvious answer on paper. Instead I went with a 400W Renogy solar array feeding a pair of Fogstar Drift 100Ah lithium batteries through a Victron MPPT. Three years on and I've genuinely never once wished I'd just run the cable.

The real revelation was freedom. No DNO conversations, no Part P paperwork, no trenching across a paddock. Just a small inverter humming away and a workspace that costs pennies to run.

That said — if you're running power tools or serious equipment daily, the mains route makes sense. Know your load before you commit to either path.

@MountainHermit solid work getting it signed off properly — Part P is not something to skip on.

That said, my garden office runs entirely off-grid and honestly I'd not go back. Got a couple of Fogstar 100Ah lithium batteries, a Victron MPPT, and two 200W panels on the roof. Powers my monitors, laptop, router, the lot — no trenching, no sparks bill.

Worth considering if you're not running anything heavy. Main limitation is winter — shorter days mean I occasionally top up via a small Victron IP22 charger plugged in from the house, but that's just a normal 13A socket job, no armoured cable needed.

Horses for courses though. If you're running a laser cutter or something power-hungry, go mains every time.

@MountainHermit £400 all in sounds decent but I'd double-check that includes the DNO notification side of things — some sparks quote low then add bits on.

Running off mains is fine if your usage is predictable, but once you start thinking about EV charging out there or anything decent in terms of load, you'll wish you'd run a bigger cable from the start. 2.5mm armoured won't cut it long-term.

I've got a small off-grid setup in my van and honestly the discipline of monitoring your actual consumption teaches you a lot. Might be worth at least slapping a Victron SmartShunt on whatever supply you end up with — knowing your real draw changes how you plan things.

Part P sign-off is non-negotiable though, @GoldenGaffer is right on that. Not just for safety — try selling your house without it.

@MountainHermit that's almost exactly what I did for my garden office — armoured cable, proper spark, Part P signed off. No regrets on that front.

BUT — and this is a genuine question rather than me being contrarian — what happens when you want to run the thing overnight in winter without the heating bills bleeding back into the house meter?

I ended up retrofitting a small Victron system with a couple of Fogstar Drift lithium batteries specifically because my usage patterns changed completely once I actually started working out there properly. Didn't see that coming when I laid the cable.

So worth asking yourself: what's the actual use case in three years' time, not just now? Extension cord — obviously no. Armoured mains — yes, probably. But is that the whole answer? Genuinely asking because I got it half right first time.