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I recently had 4 low volt lights in my hall, and 8 low volts lights in my dinning room, last night when i turned them on, the mcb tripped. has my electrician done anything wrong?

It only tripped once.
I am also having 12 low votls installed in my sitting room


2 Answers from MyBuilder Electricians

Best Answer

Probably not, but my guess is that if you look closely at the MCB (circuit breaker) that triped it will be either a BSEN60898 B6 (6amp) or a BS3871 type 2 (6amp).

In which case as you have turned on the spotlights there has been what is known as "in-rush" current. This is the higher start up current drawn when the lights are first switched on from cold, and if this current exceeds about 1.25 to 1.5 the rating on a B/type2 MCB it will cause it to trip.

The best solution is to call your electrician back and get him to fit a C type MCB and this should prevent this happening again.


Answered 7th Nov 2011

Hi Anita
Its a bit soon to say if there is something wrong.
first things first did you use a fully qualified registered electrician, like an NICEIC company did he issue you with an installation certificate with test results number of points etc. if so how long ago did he install the lights if less than a year they should be under guarantee the electrician is the first port of call for you he should be able to answer your questions.
When he added the extra lights did he add a new circuit or add them to an existing circuit it may be at the limit if he has not calculated the total load
example if he adds another 12 lights and each one uses 50watts plus some for the transformer that is 600+watts a normal 6 amp lighting circuit can cope with approximatly 1400 watts before you start to overload it. ie 1400 Watts divided by 240volts =5.83 amps.
Best practice dictates that you should really only put about 10 lights on a circuit so faults can be located and overloading will not happen 12 low voltage in one room would be fine but best on their own circuit.
I hope this is not to technical and you can work it out.
if so click the like button


Answered 7th Nov 2011

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