If your home has lost power but every switch on the consumer unit still appears to be on, the fault is not necessarily inside the consumer unit. Electricity may have been lost before it reaches the board because of a network or meter problem, or there may be a fault affecting part of the installation after the consumer unit. The pattern of the outage is the first useful clue.
What should you check first?
First establish whether the whole property has lost electricity or only certain sockets, lights or rooms. If neighbouring properties are also off, or the whole home has no supply with no obvious internal danger signs, check for a network power cut. If only part of your home is affected, an internal circuit or connection fault becomes more likely and may need electrical fault finding.
Is the problem outside the property or inside the electrical installation?
A whole-property power cut does not automatically mean there is a fault in your wiring. The electricity supply can be interrupted before it reaches the circuits protected by the consumer unit, leaving the switches physically in their normal on positions.
Several nearby properties are off
This points towards an electricity-network outage rather than a fault limited to your consumer unit. In Great Britain, power cuts can be reported through 105, which connects users with the relevant electricity network operator.
Only your whole property is off
Do not assume the consumer unit is responsible. The problem may still involve the incoming electricity supply, metering equipment or the installation within the property.
Only some rooms or circuits are off
Partial loss of power makes an internal circuit, wiring or connection issue more relevant. The affected area and what still works become useful diagnostic clues.
The meter appears to be the problem
If loss of supply is caused by a faulty electricity meter, current Ofgem guidance directs customers to their energy supplier rather than treating the problem as ordinary internal electrical repair work.
Why can the consumer unit stay on when there is no power?
A circuit breaker, RCD or RCBO does not act as a general “electricity available” indicator. Its physical position shows whether that particular device appears to have operated or been switched, but it does not prove that a healthy supply is present on the incoming side of the consumer unit.
This is especially important during complete power loss. If electricity has been interrupted upstream of the consumer unit, there may be nothing at the board for its protective devices to disconnect, so they can remain visibly on.
With partial power loss, the explanation can be different. A circuit can lose supply because of a failed or loose electrical connection, damaged wiring, a problem affecting a circuit or another fault that does not present itself simply as an obviously tripped switch.
Electrical Safety First explains that an RCD is designed to disconnect power when it detects residual-current fault conditions. It should therefore not be treated as a universal indicator for every possible electrical or supply fault.
Safe checks to make before calling someone
Useful information can be collected without removing covers, testing voltage or touching fixed wiring.
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Check whether the whole property is affected.
See whether any lighting, sockets or fixed equipment still have power.
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Check whether nearby properties also appear to be off.
If several homes or businesses have lost electricity, a network outage becomes more likely.
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Look at the consumer unit externally only.
Note whether any switch is visibly in a different position, but do not remove the cover.
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Notice whether the problem is partial or intermittent.
One room, one socket circuit or electricity that comes and goes gives a different diagnostic pattern from complete power loss.
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Remember what happened immediately beforehand.
Note whether the problem followed use of an appliance, recent building work, water ingress, unusual electrical noises or another identifiable event.
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Look for danger signs without approaching damaged equipment.
Burning smells, scorch marks, smoke, significant sparking, exposed wiring or obvious overheating change the situation from routine diagnosis to urgent safety action.
What does the pattern of the power loss tell you?
Whole property has no power
Start by considering the electricity supply before assuming there is an internal wiring fault. Network and meter-related causes sit outside ordinary circuit fault finding.
Half the property has no power
Where some circuits remain available but a substantial part of the property is off, the arrangement of the affected circuits matters. It is not enough to assume the main consumer unit has failed.
Sockets are off but lights work
This is a more localised pattern and can direct attention towards the socket circuit, its protective device, wiring or electrical connections rather than the entire property supply.
Power goes off and comes back
Intermittent power loss can be particularly difficult to identify from visual inspection alone. The timing, affected circuits and other symptoms become important during diagnosis.
When does this need electrical fault finding?
Electrical fault finding becomes relevant once a network or meter problem is unlikely and there is evidence that the loss of power is within the property's electrical installation.
Typical examples include one or more dead circuits, intermittent power, sockets or lighting that have stopped working, repeated protective-device operation or a fault that returns after appearing to clear.
In these situations,
electrical fault finding
can be used to identify the affected circuit and narrow down the cause before deciding what repair is required.
The diagnostic process may involve inspection and electrical testing of the relevant part of the installation. The exact tests depend on the symptoms and installation rather than following one fixed sequence for every power-loss call.
What if an RCD or breaker starts tripping?
Repeated tripping changes the diagnostic picture, but it still does not prove that the consumer unit itself has failed. The protective device may be responding to a fault elsewhere on the circuit or installation.
Do not repeatedly reset a device that continues to trip. Record which device operates and what electrical equipment was in use when it happened; that information can help with fault diagnosis.
A persistent RCD-specific problem is covered in more depth in
RCD Won’t Stay On? Common Reasons Why Your RCD Keeps Tripping in the UK
.
When should power loss be treated as urgent?
Urgency depends more on the electrical risk than on the inconvenience of having no power. A stable network outage and an internal electrical fault producing smoke or sparking are very different situations.
Seek urgent electrical attention where power loss is accompanied by:
- an electrical burning smell;
- significant sparking or arcing;
- visible heat damage or melting;
- an unusually hot consumer unit, socket or fixed electrical fitting;
- exposed potentially live wiring;
- water affecting electrical equipment;
- repeated dangerous electrical faults.
Where the danger is clearly within the property's electrical installation, an
emergency electrician
may be the appropriate electrical response after immediate life-safety risks have been dealt with.
Does power loss mean the consumer unit needs replacing?
No. A power cut, dead circuit or repeated trip does not by itself establish that the consumer unit needs replacing.
The fault may instead involve a circuit, wiring, electrical connection, connected equipment or the incoming supply. Replacing the board before identifying the actual cause can therefore fail to address the problem.
Consumer-unit work becomes a separate question where inspection or testing identifies an actual concern with the board, its protective arrangements, condition or suitability.
Who should you contact?
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Several properties or the local area are without electricity:
contact the electricity network operator through 105.
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The loss of supply appears to involve a faulty electricity meter:
contact your energy supplier.
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Only part of your property is affected and no network issue is present:
an electrician may need to investigate the internal installation.
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There is burning, significant sparking, overheating or another dangerous internal electrical condition:
treat it as urgent electrical work.
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There is an active fire or immediate threat to life:
get out, stay out and call 999.
Official Guidance
Guidance used for distinguishing electricity-network, meter and internal electrical issues and for the household safety advice in this article.
Power Loss Limited to Your Property?
If a network or meter problem has been ruled out and the cause inside the property is still unclear, the next step is to identify the affected circuit or electrical fault before planning a repair.
Book Electrical Fault Finding