Led wire and track lights tripping RCD intermittently...

[ericmark]

I have a 200 VA Toroidal Transformer powering my bathroom lights, not really needed it was a whim, but it has never tripped the 6A type B MCB. Now it only powers 4 LED lamps, but to start with there were 4 x 50W halogen lamps. There is only one MCB for all the house lights so I would have thought if one 200 VA Toroidal Transformer is near the limit at my house it would have taken the MCB out at some time on switching on bathroom lights, this has not happened.

Since using LED lamps one would not expect to find a 200 VA Toroidal Transformer, it would one would think be much smaller, for 200 VA looking at around £40 a 50 VA would be around £15 it does not seem to ring true that a 50 VA transformer would cause a MCB to trip unless it is faulty.

I have had MCB's tripping in other houses due to some one not reading the label, and fitting a 110 volt transformer, also had outputs grouped together out of phase.

Since LED lamps we have really no idea if it is a Toroidal Transformer, if using a DC supply then no need for a Toroidal Transformer, we have jumped to conclusions without being given the facts, can't be that hard to read what it says on the transformer and write it down on the forum. Should we not find out what is actually fitted before we consider a type C MCB?

 

[Steve Hancock]

I have installed a set of led wire and track lights however since installing them the circuit breaker trips 1 in 5 times or so that the lights actually get activated (the circuit breaker only started tripping after these new lights were installed).

At first I assumed there was a loose connection or some problem with the work that I had done (I am not a professional I hasten to add!) and so went back and checked all of the connections and wires upto the transformer - no fault found.

I then decided to leave the transformer for the lights connected to the circuit, however I disconnected the two output wires that go from the transformer and fix on to the two track wires and since then there has been no problem with the circuit breaker tripping - leading me to assume that the fault lies somewhere between the transformer and the ligth fittings themselves.

I have searched the internet but except for one vague reference in a post on this forum I have not found anything to suggest this is a common issue. If anyone has any suggestions as to what might be the problem or how to fix it, or even any knowledge of the issue it would be much appreciated. Unforunately I can't just return the lights as they were installed about four months ago just before going away for work for a considerable period, so not much chance of a refund!

thanks for any input.

Regards,

N.

 

[Steve Hancock]

I know this is probably too late a reply, but for those who are experiencing similar problems then this might be useful.
I had installed 4 LED strips using electronic transformers ( each approx 50W = 200W, less than 1A ) and found that it would always trip the 6A MCB. Uprated MCB from B to C class to overcome peak current demand but still would trip.
Then found out that the in rush current could be a high as 40A for each strip, so 4 = 160A. Solution was to use a NTC Thermistor in the live connection to each. I have used a 40 Ohm 4A, this limits the in rush current ( peak ) to about 6A and only drops less than 2 volts when fully operational temperature is reached. Can get hot so make sure its not touching anything else.
It works by droppings its resistance from 40ohm to about 4ohm when it heats up which takes about 2-3 seconds.
Have not mention Power Factor as this too has an effect on peak current when using electronic transformers.
An NTC thermistor can also be used with more traditional transformer types.