13A fuse or short out?

[timegoesby]

I have 230v dowlighters over the sink. They are fed from the downstairs lighting circuit being plugged into a socket using a normal 3 pin plug which is out of sight over the wall units. Each time one of these downlighter bulbs fails the 6AMP MCB trips and the 5 amp fuse in the plug blows. It is a pain to replace the fuse in the plug each time a bulb fails. Is it worth my while putting in a 13 amp fuse in the plug, then only the MCB will trip and I will not have use a ladder to change a fuse each time a bulb fails.

If these lights were hard wired there would be no 5 amp fuse in the way, just hard cable back top the CU. I see no reason why a 13 amp fuse cannot be fitted (or shorted out with a piece of copper wire). It doesn't look like a dangerous move to get rid of the fuse or put inthe highest rated fuse available. Any views on this?

[Andy Burns]

Replace the squarepin plug and socket with a small roundpin one which is still used on lighting circuits, and is unfused.

[Andy Hall]

The easiest solution would be to swap the plug/socket for one without a fuse - e.g. the old round pin 5A type still used for lighting.

While swapping the fuse in the existing plug might work, having this type of outlet for lighting may mean that in the future someone will mistake it for a power socket (although I suppose on top of a cupboard not all that likely.)

[The Real Doctor]

Why not just hardwire them?

Ian

[Andy Dingley]

The problem isn't with excess current, it's with an excess current of very short duration. Replace the MCB with one that's a "C curve" slow- blowing MCB -- from any decent electrical wholesaler.

If 5A fuses are blowing, and the circuit is otherwise protected, then it's not unreasonable to increase the fuse rating. _Don't_ replace the

13A with a solid link though, because that's "unexpected" and thus hazardous to anyone in the future who doesn't expect to find such a thing.

[timegoesby]

Thanks to all. As I see it, I need new slow tripping MCB """and""" a round pin fuseless plug and socket to get it to proper standards. The MCB appears the key and put a 13 A fuse in the plug and see what happens as a second cheaper option.

Only the sockets are on an RCB. Will this mean the slow tripping MCB would have made an RCB trip as well as it would not act fast enough? I am curious.

[timegoesby]

The socket and plug is already there. I could fit a square box with a terninal strip inside. I think the socket was to get around Part P. They were fitted at points around where the kitchen units were to go. The sockets were fitted then the units fitted and kitchen fitters just use flex and plus to connect up. This means a sparks does not need to be called back.

[The Real Doctor]

I was thinking of one of those things with (sometimes) a switch and a hole for a flex which often seem to be used for heaters and other immobile things. It would replace the socket. Alternatively I can't see any reason not to use a 13A fuse in the existing setup.

Ian

[The Real Doctor]

Unless there is a leak to earth the RCB should not, by my understanding, care how big the current is.

Ian

[The Medway Handyman]

Andy Dingley wrote: _Don't_ replace the

Back in the 1970's I worked for the UK's leading manufacturer (at the time) of high pressure washers - Warwick Pump & Engineering.

Larger machines had 3kW induction motors - cap start/cap run made by Brook Thompson AFAIR. Needed a min 15 amp supply.

A guy in a corner of the factory spent his time drilling out the end caps of

13 amp fuses, inserting a length of 15 amp fusewire & soldering it flush - they were a work of art!

When they invariably blew due to low voltage it was quite common for the punters to replace them with silver steel/cut off bolt of the appropriate diameter.

I once found one wired up with about 10 metres of 2.5mm T&E cable with a 13 amp plug on the end.

[Dave Plowman (News)]

Assuming the wiring downstream of the plug is up to it, using a 13 amp fuse would satisfy the regs IMHO. It is only there to protect that wiring

- the MCB looks after the permanent stuff. That the permanent wiring is protected by an MCB of lower rating the than the plug fuse doesn't matter. It's rather the same as fitting say a 6 amp MCB to a normal 2.5mm final ring circuit. It would severely limit the usefulness of that ring but be perfectly safe.

Don't wire out the plug fuse, though. If you wish to dispense with it, change to a 2 or 5 amp round pin unfused plug/socket which is the norm for this sort of lighting use.

[John Rumm]

I would go along with using the lighting round pin plugs (use a modern shuttered one and not an old cast off), and possibly changing the MCB to a type C.

Another option would be to replace the downlights with low voltage versions.