Tired fuse

[LesWilcock]

Dear forum members

I don’t anticipate this will extent the capabilities of the forum too much but any advice would be appreciated.

I have a WYLEX consumer unit controlling a kitchen extension (built 2006). One of the RCD’s (6 amp ) has taken to tripping 4 or 5 times a day. It monitors the lights in the kitchen, cupboard units, toilet and outside light.

In an effort to isolate what’s causing the overload I have sequentially left things on but no combination stops it tripping. The most bizarre (to me ) is with everything switched off (say overnight), in the morning it tripped.

My dilemma is, is it the fuse or is there something tripping it. I guess the simple answer is to buy another fuse and swap it over (which I will do anyhow). If it fixes it, then great, if not it’s a case of calling my local electrician.

Many thanks in anticipation

Les Wilcock

Edit: Might not be important but in my previous post I refered to a RCD and its in fact a Wylex NSB06 which I believe is a MCB
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Mod 3

Welcome to the forum, there is a edit tab to update your topic, I have done it for you.

 

[ban-all-sheds]

One of the RCD’s (6 amp ) has taken to tripping 4 or 5 times a day. It monitors the lights in the kitchen, cupboard units, toilet and outside light.

Do you mean RCD?

I suspect you mean MCB - the device tripping doesn't have a test button, does it?

In an effort to isolate what’s causing the overload I have sequentially left things on but no combination stops it tripping. The most bizarre (to me ) is with everything switched off (say overnight), in the morning it tripped.

If there's a fault with the wiring rather than a light then leaving them switched off won't do any good.

Have you done any work anywhere in the house recently? Doesn't have to be electrical.

Can you find where the outside light is connected to the lighting circuit, and disconnect it completely at that point?

I guess the simple answer is to buy another fuse and swap it over (which I will do anyhow). If it fixes it, then great, if not it’s a case of calling my local electrician.

My prediction is that it won't fix it.

 

[chivers67]

I'd do what B-A-S suggested first, then if that hasn't cleared the fault you'd be better of finding the furthest light on the circuit (which may or may not be the external light) disconnecting the wiring and working back to the board until it stops if you've not got access to test equipment.

 

[LesWilcock]

Thanks for the comments.

The outside light is a) the furthest point on the circuit, b) changed a bulb recently, but its gone again and c) will be switching itself off and on via the dusk to dawn switch irrespective of what internal lights I switch on. So was definatly the prime culprit in my mind if it was a genuine fault.

The only thing that was confusing me was it doesn't trip immediatly you reset it, even with all the lights on but thats in daylight when the outside light is off.

Regards

 

[holmslaw]

..

 

[bongos]

Might not be important but in my previous post I refered to a RCD and its in fact a Wylex NSB06 which I believe is a MCB

This suggests that you have a L/N fault of high impedance on this circuit. It's not enough to trip the MCB immediately but will after a while. As suggested already, completely disconnect your outside light from the supply. Check the fitting for signs of damage and any damp.

You could also open the other light fittings on the circuit and check that nothing has become loose or damaged.

But as others have said - my money's on the outside light too.

 

[kai]

Why don't they bring the back the Regulation which demanded a double pole switch with neon indicator between an outside light and internal wiring circuits???

In the Eighties, I believe that this was the case, perhaps someone can confirm this or otherwise - it was such a good safety idea - but why was it abandoned in the 16/17th editions???

 

[securespark]

I have looked quite deeply into the regs, but cannot find what you refer to.

In the 15th (brown cover), 537-7 says that isolation shall be achieved preferably by the use of multipole devices.

That seems to be the closest I can get to what you refer.

In the 16th (yellow cover), that is 537-02-08. The same reg number survives in the final 16th Ed (brown cover), but it is much changed.

I am now ploughing through the 14th Ed, but cannot find any references as yet.

 

[riveralt]

I'm with Kai on this one. I have always fitted an fcu between the outside light and internal circuits just a personal preference - I thought it was in the regs.

Mind you I have seen it in several manufacturers fitting instructions.