What size consumer unit do I need – Advice from Electriman, North London Electricians

What Size Consumer Unit Do I Need?

Your consumer unit (also called a fuse board or distribution board) is the heart of your home's electrical system. Choosing the right size means having enough circuit breaker slots — called ways — for every circuit in your home, plus room for future additions.

What Does 'Size' Actually Mean?

The size of a consumer unit refers to the number of ways it has — each way holds one MCB (miniature circuit breaker) or one RCBO. It does not refer to physical dimensions, though larger units are physically bigger.

How Many Ways Do Typical Homes Need?

1–2 bedroom flat: 6–8 ways

2–3 bedroom house: 10–12 ways

4 bedroom house: 12–14 ways

Large or extended home: 14–16 ways or a dual split-load board

What Circuits Count Toward the Total?

Every separate circuit needs its own way. Common circuits include:

Lighting — typically one per floor

Ring main sockets — usually one per floor

Cooker or oven circuit

Shower circuit

Immersion heater

Garage or outbuilding

EV charger

Solar PV or battery storage

Underfloor heating

Alarm systems or CCTV

What Should You Check?

You can safely count your existing circuits by:

1. Looking at the number of breakers already in your current consumer unit

2. Checking if any spaces are already full or if breakers are doubled up (a sign the board is too small)

3. Thin

Need a qualified electrician in North London?

Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.