The best way to power a remote shed or outbuilding depends on how far it is from your house and what you need to run. For sheds up to 30-50 metres away, a cable from the house is often the most practical option. Beyond that, or where cable trenching is too disruptive, a standalone solar system with a battery bank is the most cost-effective and practical solution for the majority of outbuilding power needs.
A powered shed or outbuilding transforms what you can do with the space. Whether it's a workshop, a home office, a gym, a stable, or a garden room, having reliable electricity makes the space genuinely usable year-round. When mains cable isn't a practical option, solar is often the answer.
Should You Run a Cable or Go Solar?
Running an armoured cable from your house is the traditional approach, but it has real costs and constraints:
- Trenching and armoured cable: £15-£30 per metre for professional installation
- Consumer unit and wiring at the outbuilding: £500-£1,500
- Planning considerations if the building is in a conservation area or near boundaries
- Ongoing electricity cost added to your bills
For a shed 10 metres from the house, a cable is usually the simplest and most practical approach. For a shed 50-100 metres away across a paddock or field, a solar system is often more affordable and certainly less disruptive.
Sizing Your Solar System
Work out what you need to power and how often. Common outbuilding loads include:
- LED lighting: 5-20W per fixture
- Laptop or monitor: 45-80W
- Phone and device charging: 10-30W
- Power tools (occasional): 500-2,000W bursts
- Electric heater: 1,000-2,000W continuous
- Small fridge: 50-80W average
- Security camera system: 10-30W
Electric heaters are the biggest challenge for solar systems. If space heating is a priority, consider a wood-burning stove or a diesel/propane heater instead, using solar power for everything else.
Component Guide
Solar Panels
Rigid monocrystalline panels mounted on the shed roof or on a ground-mounted frame are the most common approach. Size the array to generate your daily energy requirement in the available peak sun hours. In the UK, plan around 3 peak sun hours per day as an average across the year.
For a workshop or home office with moderate daily use (lighting, laptop, device charging), a 400-800W array is a sensible starting point.
Battery Storage
LiFePO4 batteries are the best choice for an outbuilding installation. They're maintenance-free, last a decade or more, and perform well in the temperature range found in a UK shed (though extreme cold below 0°C reduces charging efficiency). Size the battery bank to cover at least two days of use without solar input.
Inverter/Charger
A combined inverter/charger unit handles both converting battery power to 230V AC and managing charging from solar and any supplementary sources (such as a generator or shore power connection). These all-in-one units simplify wiring considerably. Size the inverter to handle your largest expected load.
Charge Controller
An MPPT charge controller is recommended for any system of 200W or more. It sits between the solar panels and battery bank and maximises energy harvest. Match the controller to your panel array's voltage and current specifications.
All-in-One Approach: Solar Generator
If you want to avoid the complexity of designing and wiring individual components, a solar generator provides a complete solution in one unit. The EcoFlow DELTA Pro, for example, combines a 3,600Wh battery, inverter, AC outlets, DC outlets, and USB charging in a single portable unit. Pair it with one or two roof-mounted solar panels via an MC4 cable and you have a functioning power system with minimal installation work.
This approach works particularly well for home offices, garden rooms, and workshops where you want reliable power without a complex electrical installation.
Wiring the Outbuilding
Even with a solar-powered outbuilding, internal wiring should be carried out to the same standard as a mains-connected building. Use appropriate cable ratings, include an RCD for personal safety, and install proper mounting and containment for all wiring. A registered electrician should carry out or sign off any fixed wiring installation.
Security and Weatherproofing
- Mount panels securely with anti-theft fixings where possible
- Run cable between the panels and battery in conduit or armoured cable to prevent rodent damage
- Store batteries in a well-ventilated, frost-protected location where possible
- Use weatherproof outdoor-rated solar junction boxes for any exterior connections
Example System for a Home Office Shed
A practical, proven specification for a year-round home office in a garden shed:
- 2 x 400W mono solar panels on a south-facing roof mount
- 40A MPPT charge controller
- 200Ah LiFePO4 battery
- 2,000W pure sine wave inverter/charger
- Consumer unit with RCD and appropriate circuit breakers
Total installed cost is typically £1,500-£2,500 depending on labour and cable runs, often comparable to or cheaper than running an armoured cable for more distant outbuildings.
