Generator installation

Power cuts in South Wales are rare but increasingly disruptive, particularly for home-office workers, small businesses, medical practices and anyone running freezers or critical equipment. A properly installed standby generator picks up the load within seconds and runs for as long as there’s fuel.

Standby generators

Permanently mounted, fuel-fed (LPG or diesel), with an automatic transfer switch (ATS) that detects a grid outage and starts the generator without intervention. The generator typically takes 8–12 seconds to come online; the ATS swaps the property load over once the generator is at full speed.

Typical 8 kW domestic install: £4,500–£6,500 fitted and certified, depending on cabinet, fuel storage, and whether new earthing is needed.

What’s involved:

• Concrete slab + acoustic cabinet: the generator sits outside in a sound-insulated cabinet (typical noise rating 60–70 dB at 1m, dropping fast with distance).
• Fuel storage: either an underground LPG tank (typically 1,200–4,000L for residential) or a daily-service diesel tank (200–500L).
• Auto-transfer switch: wired between your main service and your consumer unit. Detects grid loss, signals generator to start, swaps load.
• Generator: Honda, Briggs & Stratton, Generac, or Kohler depending on output. We’re trained on all four.
• Annual service contract: every standby unit needs annual testing and oil changes. We book the schedule with you.

Portable / inlet generators

A simpler option: a manually started portable generator plugged into a wall-mounted inlet socket that powers selected critical circuits via a transfer panel. From £1,200 for the inlet and panel, plus your choice of generator (typically £600–£1,500 for a quiet 3–6 kW unit).

When the power goes out, you wheel the generator outside, fire it up, plug it into the inlet, and flip the switches on the transfer panel for the circuits you want powered (typically: fridge, freezer, broadband router, a couple of lights, kitchen ring main, central heating control). Comes back on in 5 minutes and runs for as long as you’ve got petrol.

This is the right choice for most domestic users who want resilience for a £30/year of standby electricity bill. The portable can also be borrowed for camping, weddings, garden parties, unlike a standby that’s permanently mounted and dedicated to grid-failover.

Critical-circuits panel

For both standby and portable installs, the critical-circuits panel decides what gets powered when the generator runs. Typical choices:

• Always on: boiler, fridge/freezer, broadband, security alarm, key lighting circuits.
• Sometimes on: kitchen ring (cooking + dishwasher), washing machine, immersion heater.
• Off during outage: electric shower (high load), tumble dryer (high load), EV charger (very high load), pool/hot-tub.

We program the panel based on your generator size and your priorities at survey.

DNO notification

Generators that export back to the grid (parallel-running) need DNO notification and approval. The vast majority of domestic and small-commercial generators are island-mode: they run on their own when grid fails and disconnect when grid returns. These don’t need DNO notification.

We’ll confirm at survey which category your install falls into.

Earthing: the bit most installers miss

Generator earthing is more nuanced than grid-supply earthing. Depending on your supply type (TN-S, TN-C-S, or TT) the generator may need a separate earth rod and an O-PEN device, or may bond into the existing earth, or may need a switched earth via the ATS.

Getting this wrong is dangerous and is the most common reason a generator install fails an EICR or insurance check. We design the earthing per BS 7671 from day one.

Common mistakes other firms make

• Skipping the auto-transfer switch. Without an ATS, the generator can backfeed into the grid, which is illegal and dangerous. We never install a standby unit without an ATS.
• Wrong-sized fuel tank. A 200L tank lasts 8–12 hours on an 8 kW generator. For multi-day grid failures, you want 600L+ or refill arrangements pre-booked.
• No acoustic enclosure on residential standby. Neighbour relations matter. We always specify cabinets that hit residential noise targets.

Pricing

• Manual-start portable + 4-circuit inlet panel: £1,200–£1,800 + your portable generator.
• 8 kW LPG standby + ATS + slab + acoustic cabinet: £4,500–£6,500 + LPG tank install (typically £1,200–£2,800 separately).
• 11 kW LPG/diesel standby (whole-house): £6,500–£9,500 + tank.

Workmanship and warranty

12-month workmanship warranty on every install. Manufacturer warranties: Honda 3 years, Briggs & Stratton 2 years, Generac 5 years, Kohler 5 years (extendable to 7 with annual service). Annual service contracts available: typically £180/year covering oil change, filter change, full test cycle.