When 'Sockets' Isn't an Answer: Mapping Your Consumer Unit Like You Mean It

A consumer unit label is not a sticky note. It is the map someone reaches for when the lights go out, the socket starts tripping, or a small business needs to isolate the right circuit without plunging the wrong part of the building into darkness.

And yet, in 2026, plenty of UK consumer units still carry labels that say 'sockets', 'lights', 'spare' and very little else. That is not a circuit description. It is a guess with a sticker on it.

This guide is about fixing that. Not with fancy labels for the sake of it, but with a proper circuit schedule that tells the truth.

Why 'sockets' is not a circuit description

A modern home rarely has one socket circuit. It might have a kitchen ring final, a downstairs ring, an upstairs radial, a utility circuit, an outdoor socket, a garage supply and a dedicated feed for the boiler or immersion heater. 'Sockets' tells you none of that.

'Lights' is just as slippery. Upstairs lights, downstairs lights, outside lights, loft lights and emergency lighting can all be separate. If the label says 'lights' and only half the house goes dark, the label is lying to you. In a fault, that lie costs time.

For small businesses, the problem is sharper. A label that says 'kitchen' might cover the fridge, the till, the microwave and the back-office socket. A label that says 'office' might not mention the server cabinet, the alarm or the CCTV. When something trips at 7am, vague labels turn a two-minute isolation into a twenty-minute hunt.

What a proper circuit schedule contains

A circuit schedule does not need to be beautiful. It needs to be accurate, durable and readable. For each way in the consumer unit, record:

• The circuit number, matching the physical position in the unit.
• A plain-English description of what it serves and where.
• The protective device rating and type, such as 32A MCB or 6A RCBO.
• Which RCD group protects it, if it is not an RCBO.
• Cable size and type where known, such as 2.5mm twin and earth.
• Key equipment on the circuit, such as fridge/freezer, fire alarm or server rack.
• Any useful notes, such as 'includes outside socket' or 'excludes loft'.
• The date and initials of the person who checked it.

A good label might read: 'C1 Kitchen ring final - 32A MCB - RCD1 - includes utility sockets'. Another might say: 'C4 Upstairs lights - 6A MCB - RCD2 - excludes loft'. That is not clutter. That is information.

Use a proper label printer or durable printed schedule. Marker pen on masking tape has a habit of curling up, fading or falling off exactly when you need it. If the label cannot be read from standing height with a torch, it is not finished.

Mapping without opening the lid

You do not need to remove the consumer unit cover to map circuits. In fact, you should not. Leave the inside of the unit to a competent electrician.

A safe basic mapping exercise looks like this. Turn off appliances and unplug sensitive equipment first. Then switch off one breaker at a time and note which sockets, lights or fixed appliances stop working. Use a plug-in socket tester or a lamp to check sockets. Keep a notebook or take photos. Work methodically, and do not rush.

For RCDs, identify which breakers sit under which RCD group. Press the RCD test button and note which circuits go dead. For RCBOs, each device has its own test button, so test them individually. If the labels do not match what happens, stop guessing and book an electrician. The consumer unit is not a puzzle box.

For a business, do this outside trading hours or plan the downtime properly. A quick mapping session that knocks out the tills, the alarm or the server is not a quick session.

Label for the real world, not the showroom

Good labelling is about the questions people actually ask. Which circuit feeds the outside socket? Which one runs the fridge? Which one must not be switched off without warning? Which RCD protects the bathroom circuit?

Write labels as if the reader is stressed, in a dark hallway, with a torch in their mouth. Use plain words. Avoid codes unless there is a key. If a circuit is genuinely spare, say 'Spare - no connected equipment' rather than leaving a mystery. If a circuit feeds critical equipment, say so: 'Fire alarm - do not isolate without authorisation' or 'Server rack - UPS on circuit'.

At home, useful labels include 'Kitchen sockets - includes fridge/freezer', 'Immersion heater - timed supply' and 'Outdoor sockets - RCD protected'. In a small business, add 'EPOS till', 'CCTV', 'Access control' and 'Emergency lighting' where relevant. The label should serve the person who has to act, not the person who installed it.

Test your labels, then keep them true

A label is only useful if it matches reality. Check it after any extension, loft conversion, kitchen refit, EV charger installation or new outdoor socket. Check it when you move into a property. Check it when you take over a business premises. If the schedule has not been updated since the last change, it is already drifting.

Keep a printed copy of the circuit schedule near the consumer unit and a photo of it on your phone. If you have an EICR, keep the schedule of circuit details and schedule of test results with it. They are the reference point, not the faded sticker from years ago.

Finally, test the labels in the way they will be used. Can someone isolate the right circuit in ten seconds? Does the RCD mapping hold up? Does 'sockets' actually mean all the sockets, or just the ones the last owner remembered?

A good label is cheap. A wrong one is expensive. Make yours mean something.