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Upstairs Circuit Keeps Tripping
The circuit supplying power upstairs keeps tripping, leaving the upstairs without electricity.
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What's happening?
In many UK homes, the socket and lighting circuits are split between upstairs and downstairs, each with their own MCB. When the upstairs circuit keeps tripping, the fault is somewhere in the upstairs wiring or in an appliance used upstairs. Common culprits include bedroom appliances, bathroom fittings, and loft wiring.
What usually causes it?
- Faulty appliance in a bedroom such as an electric blanket, hair dryer, or heater
- Moisture in a bathroom fitting such as a shower isolator or extractor fan
- Damaged cable in the loft where wiring runs between rooms
- Overloaded upstairs ring circuit with too many high-draw appliances
- Faulty socket in a bedroom or landing
- Loft conversion wiring that was done incorrectly or has developed a fault
Is it dangerous?
The same risks apply as with any tripping circuit. Bathroom-related faults are of particular concern because of the proximity to water. If the upstairs lighting circuit is also affected, you may need to use stairs in the dark, which is a fall hazard.
Can I fix it myself?
Identify which MCB has tripped and reset it. Unplug all appliances upstairs and try again. Pay particular attention to bedside lamps, electric blankets, heaters, and bathroom appliances. Plug items back in one at a time. Check bathroom fittings for any signs of moisture or condensation.
When should you call an electrician?
Call an electrician if the circuit trips with nothing plugged in upstairs, if you suspect a bathroom fitting is the cause, if you have a loft conversion that may have wiring issues, or if the problem is affecting both sockets and lights upstairs.
What will the electrician actually do?
- Identify which upstairs circuits are affected (ring main, lighting, or both)
- Test the upstairs wiring with insulation resistance testing
- Inspect bathroom fittings, loft wiring, and bedroom sockets for faults
- Check any loft conversion wiring for compliance and faults
- Repair the fault and test the circuit to confirm safe operation
What will it cost to fix?
£100–£250
Access to upstairs wiring may involve working in the loft. Costs increase if cables are hidden within walls or under floors and need to be accessed.
Find an electricianFrequently asked questions
We’re happy to answer all your questions.
Why does only the upstairs keep tripping?
Your home likely has separate circuits for upstairs and downstairs. A fault in the upstairs wiring or an appliance used upstairs will only affect the upstairs MCB.
Could my electric blanket be the cause?
Yes. Electric blankets are a common cause of tripping, especially older ones with deteriorating insulation. They should be tested annually and replaced if they show any signs of damage or wear.
Is the bathroom wiring a common problem?
Bathrooms are high-risk areas for electrical faults because of moisture. Extractor fans, shower isolators, and heated towel rails can all develop faults, particularly if seals or connections have deteriorated.
Could a loft conversion be the cause?
If the tripping started after a loft conversion, the new wiring could be at fault. Loft conversion electrical work must comply with BS 7671 and be certified. Non-compliant work is a common source of problems.
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