Intermediate lighting fault

[Ardmore]

I've been working on an intermediate circuit with 4 switches. 2 two ways and 2 intermediates. They only operate 4 gu10 bulbs. Sometimes, in certain states the lights will not come on with some switches . And sometimes the mcb will trip also. Sometimes it trips straight away and other times it trips after a few seconds. Nothing has changed as far as the wiring is concerned. What is the problem??? How can I resolve it!!!???[/b]

 

[EFLImpudence]

For an MCB to trip there must be either -

an overload or -

a short circuit.


Are there lots of lights on the circuit?

As the switches do not seem to be working properly there could be a loose wire somewhere

 

[securespark]

It seems there is only a maximum of 200W loading.

From the POV of the switching fault, as the switching fault is not constant, there must be either a loose or broken strapper or a dodgy switch.

However, unless there is more than one fault, that would not account for the MCB tripping as well as the odd switching behaviour.


Those faults could include:

overload (if there is greater than 200W load - also dependent on the MCB rating and type

short circuit (damaged cable, by heat (cable burnt by proximity to lamp), penetration (picture hook on wall above switch drop or cable run, screw through cable when boarding out loft or through floorboard etc)

faulty MCB (sometimes MCB's become mechanically faulty and don't latch properly, clicking off. This can be ascertained by IR testing the circuit and, if healthy, swapping out the circuit breaker).

 

[EFLImpudence]

It seems there is only a maximum of 200W loading.

That's all operated by these switches.
There could be a couple of electric fires elsewhere.

From the POV of the switching fault, as the switching fault is not constant, there must be either a loose or broken strapper or a dodgy switch.

Shorting to earth ???

However, unless there is more than one fault, that would not account for the MCB tripping as well as the odd switching behaviour.

Could be.

Those faults could include:

overload (if there is greater than 200W load - also dependent on the MCB rating and type

short circuit (damaged cable, by heat (cable burnt by proximity to lamp), penetration (picture hook on wall above switch drop or cable run, screw through cable when boarding out loft or through floorboard etc)

faulty MCB (sometimes MCB's become mechanically faulty and don't latch properly, clicking off. This can be ascertained by IR testing the circuit and, if healthy, swapping out the circuit breaker).

We may never know.