Fuse Keeps Blowing?
Repeatedly blown fuses indicate an underlying electrical issue that needs professional attention. Our CHAS approved electricians diagnose and fix the root cause.
Solutions Ltd
Why Does My Fuse Keep Blowing?
A rewirable fuse contains a thin wire rated to carry a specific current – 5A for lighting, 15A for immersion heaters, 30A for ring circuits. When more current flows than the wire can handle, it melts and breaks the circuit. That's the fuse doing its job. The danger comes when people replace it with thicker fuse wire or – worse – wrap it with foil. We've seen both in Devon properties and both are genuine fire risks.
If you're replacing the same fuse repeatedly, there's an underlying fault. The most common cause in older installations is degraded cable insulation allowing conductors to touch intermittently – this creates a short circuit that blows the fuse instantly. We diagnose this by measuring insulation resistance on the affected circuit. A healthy circuit should read above 1MΩ; anything significantly below that indicates breakdown that will only worsen over time.
If your home still has a rewirable fuse board, we'd strongly recommend upgrading to a modern RCBO consumer unit. Unlike rewirable fuses, RCBOs provide both overcurrent and earth fault protection on every circuit individually – so one fault only affects one circuit, not half your house. We fit Hager or Schneider boards as standard, with full certification under BS 7671.
Common Causes
Circuit Overload
Too many appliances drawing power from a single circuit exceeds the fuse rating, causing it to blow repeatedly.
Short Circuit
Live and neutral wires touching creates a surge of current that instantly blows the fuse as protection.
Faulty Appliance
A damaged appliance with internal electrical faults draws excessive current or causes shorts.
Wrong Fuse Rating
Using a fuse with the wrong amperage for the circuit it's protecting will cause premature blowing.
Deteriorated Wiring
Old or damaged insulation on cables can cause intermittent short circuits that blow fuses.
Loose Connections
Poor connections at terminals can cause arcing, which generates heat and eventually blows fuses.
When to Call an Electrician
- The same fuse blows repeatedly after replacement
- You can smell burning near the fuse board
- Multiple fuses blow at the same time
- You're not sure which fuse rating to use
- The fuse board uses old rewirable fuses
- You can't identify what's causing the problem
Frequently Asked Questions
Why does my fuse keep blowing?
Fuses blow due to circuit overloads, short circuits, faulty appliances, or deteriorating wiring. If the same fuse blows repeatedly, there's an underlying electrical problem that needs professional diagnosis.
Should I replace blown fuses with higher rated ones?
Never use a higher-rated fuse than specified. Fuses are sized to protect the circuit wiring. A higher-rated fuse won't trip when it should, risking overheating and fire.
Should I upgrade to circuit breakers?
Yes. Modern consumer units with MCBs and RCD protection are much safer than old fuse boxes. They're faster acting, resettable, and provide additional protection. Upgrades cost £350-£600.
Our content is regularly reviewed by qualified electricians to ensure accuracy.
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Frequently Asked Questions
Why does my fuse keep blowing?
Repeated fuse blowing indicates an overloaded circuit, a short circuit in the wiring, or a faulty appliance drawing too much current. The fuse is doing its job protecting you — the underlying cause needs fixing.
How much does it cost to fix a fuse that keeps blowing?
Diagnosis starts at £80 plus VAT. If it's a faulty appliance, the fix is simple. If it's a wiring fault, repair costs range from £100-£400. A consumer unit upgrade (from £499 plus VAT) may be recommended for old fuse boxes.
Should I replace my old fuse box?
If your fuse box uses rewirable fuses rather than MCBs, upgrading to a modern consumer unit with RCD protection is strongly recommended. This provides better safety and eliminates repeated fuse wire replacement.
Can I just use a bigger fuse wire?
Never use a larger fuse wire — this defeats the safety protection and can cause cables to overheat, potentially starting a fire. Always use the correct rating fuse and have the underlying fault investigated.