Is fitting a bigger fuse a solution?
No. The fuse rating was chosen to suit the cable cross-section, not the device; enlarging it leaves the cable unprotected and does not remove the fault, it only makes it invisible. While the overcurrent continues, the cable rises above its permitted temperature, the insulation degrades and a fire risk appears. The correct approach is to measure the current and find the cause, and if it really is necessary, to increase the cross-section first.
The fuse rating had been chosen between two limits: above the device's continuous current, below the capacity of the thinnest cross-section on the line. When you increase the rating you exceed the upper limit, meaning the protection no longer protects the cable.
What happens: in a short circuit or overload, the current flows freely up to the new fuse rating. The cable was not selected to carry that current; it heats up, the insulation softens, it touches neighbouring cores and the fault grows. Meanwhile the fuse stays intact, because a higher threshold is now holding it.
The correct order:
- Measure the real current with a clamp meter and compare it with the device's expected value.
- If the current is above expectation, find the cause mechanically or electrically: a jammed mechanism, a seized bearing, a partial short circuit.
- If the current is normal, the fuse type or its holder is the problem; switch to a type suited to the inrush current or replace the overheated holder.
- If the device really does require a higher current, increase the cable cross-section first, then raise the fuse to suit the new cross-section.
As a rule, raising the fuse rating is only legitimate when the whole line has been renewed to carry the new rating.
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