Partial Power Loss in a London Property: What Should You Do?
Safe triage when one floor, room or group of circuits goes off
Partial power loss usually means one circuit, protective device, phase or connection has been affected while other supplies remain available. Check for fire, smell, heat, water and damage first. Then identify which areas are off without opening electrical equipment. Repeated tripping or unexplained loss needs professional fault finding.
First decide whether there is immediate danger
If there is smoke, a burning smell, sparking, water near electrical equipment or a shock, keep away and treat the situation as an emergency. Call emergency services for fire or injury. Do not enter a flooded area to reach the consumer unit.
When there are no danger signs, note what remains on. Lights may work while sockets do not, one floor may be affected, or only equipment supplied through a particular distribution board may be off.
Check whether the issue is internal or external
Look outside to see whether street lighting or neighbouring properties appear affected, and check the network operator's outage information. A supply problem can affect one property or one part of a multi-phase service, so the absence of a street-wide outage does not prove the fault is internal.
In flats and mixed-use buildings, communal intake equipment or landlord supplies may require the building manager or freeholder as well as an electrician.
Safe observations at the consumer unit
Only approach the consumer unit if it is dry, undamaged and not hot. Note which protective device has operated. Do not remove covers. Unplug portable appliances on the affected circuit before one cautious reset, and stop if it trips again.
A breaker that appears on does not guarantee the circuit is healthy. There may be a disconnection, a local fused device or a fault elsewhere.
Protect appliances and avoid unsafe workarounds
Switch sensitive equipment off until the supply is stable. Do not run multiple high-load appliances from a single extension lead connected to another room. Refrigeration, alarms, medical equipment, servers and access systems may need a specific continuity plan.
For businesses, record the time of failure and equipment affected. This supports both diagnosis and operational reporting.
What the electrician will investigate
Fault finding may include verifying the incoming supply, inspecting protective devices, testing affected circuits and checking connections at relevant points. The electrician should separate the confirmed fault from unrelated recommendations and explain whether the repair is temporary or permanent.
Intermittent power loss may require monitoring or staged isolation. A clear history of when it occurs is valuable.
Frequently asked questions
Why is half my flat without power?
The affected rooms may share one circuit or protective device, or there may be a local connection fault. In some installations, a supply issue can affect only part of the system.
Should I call the network operator or an electrician?
Check the network outage service first. If the problem is limited to your property, involves internal warning signs or remains after supply is confirmed, call an electrician.
Can partial power return by itself?
Yes, intermittent connections and supply faults can appear to recover, but that does not make them safe. Arrange investigation if the cause is unknown.
Next step
Call the emergency line when partial power loss is accompanied by heat, smell, arcing, water or critical service failure; otherwise book structured fault finding promptly. Call 020 3038 6072 or use the website enquiry form to discuss the property or premises.