Consumer unit replacement in Maryculter, for farmhouses, steadings and homes with outbuildings.

Whatever you call it, the consumer unit is the box that takes the incoming mains supply and splits it into the individual circuits that serve your home, then protects each one. A modern board built to BS 7671 (18th Edition) uses a non combustible enclosure, usually metal, an RCBO on every circuit, surge protection (SPD), and an AFDD where it is appropriate.

Each device does a specific job. An RCBO combines overload protection with earth fault protection in a single unit, so one circuit faulting trips only that circuit rather than half the house. An SPD clamps voltage spikes coming in off the supply before they reach your appliances. An AFDD detects the arcing that can start a fire in a damaged or loose connection.

Older boards did less. A rewireable fuse only melts a wire when too much current flows, with no earth fault detection of any kind. That is the difference between a 1960s board and a board fitted today, and it is why an upgrade is about safety first, compliance second.

We still find rewireable fuse boards in older Maryculter farmhouses that have never been upgraded. These boards use a length of fuse wire in a carrier that melts when too much current flows, sit in an old plastic enclosure, and offer no RCD protection, no surge protection, and no easy way to tell which circuit is which.

The signs that a board is due for replacement are usually clear:

• Old rewireable wire fuses or an old plastic enclosure.
• No RCD protection on the board at all.
• Frequent tripping, or fuses that keep blowing.
• Scorching, discolouration or a burning smell around the board.
• It has been flagged on an EICR.

A direct replacement with a modern metal RCBO consumer unit brings the installation up to the 18th Edition and starts at £550 to £950 + VAT for a typical 100A domestic supply. Where the property has sub boards or a three phase supply, we confirm the figure after a survey.

Town supplies are mostly buried. A lot of the supply around Maryculter and the South Deeside Road runs overhead, which makes it more exposed to lightning activity and voltage spikes. Those surges travel down the line and into the house, and they are exactly what damages boilers, inverters, EV chargers and the electronics in modern appliances.

A surge protection device (SPD) fitted in the consumer unit clamps those spikes before they reach your circuits. On a modern board it is a small addition that protects a lot of expensive kit, and on a rural overhead supply it earns its place more than it would in the city. We fit SPD as standard on board upgrades and can add one to a suitable existing board for £40 to £80 + VAT.

Where a property also runs renewables, the SPD protects the inverter and battery management electronics too, which are the costliest things to replace after a surge.

A board usually gives some warning before it fails. The signs are easy to ignore on a board tucked in a porch or an outbuilding, but they should never be left. In every case the right response is to switch off the main switch and call a qualified electrician the same day.

• Burning smell. Melting insulation, usually a loose connection arcing inside the board.
• Scorch marks or discolouration. Visible heat damage on the board, terminations or cable insulation.
• Frequent tripping. A breaker or fuse that goes when nothing in particular has changed.
• Old plastic enclosure with wire fuses. No RCD protection, and overdue regardless of symptoms.

If you see any of these in your Maryculter home, turn off the main switch, the largest switch on the board, and call us on 07304 027013. We attend rural South Deeside properties for urgent board issues, and we will tell you honestly whether it is a repair or a replacement.