Led wire and track lights tripping RCD intermittently...

[fullern]

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.

 

[333rocky333]

Wire track tends to use Toroidal Transformers, there is a lot of "Inrush current" with these and are prone to tripping mcb's usually "B" type ones, sometimes a soft start transformer or dimmer is better.
Electronic Transformers are not used due to EMI from the length of wires

View the similar threads at bottom of the page

 

[Taylortwocities]

Can we check your terminology. Do you mean RCD, or is it an MCB that is tripping? Its important as they do diffrent jobs. This pic may help:

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

 

[fullern]

Hi and thank you very much for taking the time to reply.

@Rocky333 = I am afraid I don't know anything about toroidal transformers but I will look it up and hopefully that will help make sense of what you are saying. understood that the inrush current can 've a factor. would these issues not still be present even if the actual track was not wired to the transformer?

@Taylortwocities - I believe it is the mcb tripping according to your picture. I have taken a photo so you can correct me if I'm wrong. It is the breaker marked 'lights'.

Thanks!

N.

 

[Taylortwocities]

Yes, it sounds like the MCB does not like the inrush current. You'll probably find it's ok if no other lights are being used at the same time?

There is a solution, and that is to change the MCB to a 6amp type C. But there are some checks that an electrician needs to do before it is changed.
So you need a sparky.

 

[333rocky333]

bits of this post may help you understand

https://www.diynot.com/diy/threads/why-are-my-lights-tripping.341255/

 

[fullern]

Electrician has now been called.

@Rocky333 - I looked up the toroidal transformers and get the gist of it along with current insurge.

Hopefully upgrading the MCB will do the trick.

Thank you both for your help.

N.

 

[bernardgreen]

It may be worth considering a different type of transformer. Toroidals are not the optimum choice for large lighting loads in domestic applications due to in rush.

Some snippets from the conversation with a transformer manufacturer about the design of a bespoke transformer for a lighting installation of 372 incandescent 2 watt lamps at my daughter's wedding.

These confirm that inrush into a toroidal transformer is higher than for a laminated transformer but the losses are higher with laminations.

According to my calculations you should have 12.27V at no load and 12V at 50A on the 240V tap (*). Knowing about your application I allowed all taps to cope with at least 10% voltage overload.

Multiple secondaries is not a problem - but on one transformer inrush could still be an issue

We could supply a thermistor to fit in series with the primary winding which reduces the inrush , we can wind in such a way to minimise inrush , and use a core which limits inrush - but with a toroid there will always be a level of inrush

The laminations chosen should give you good efficiency, about 96-97% as opposed to 99% that would be expected from a highly efficient toroid on highly efficient material without the large inrush associated with the high efficiency material. I have compensated for the losses in the winding.

(*) 240 volts fed to the 240 volt primary tap

the lamps were under run so the total load was less than 600 watts

 

[stillp]

Hopefully upgrading the MCB will do the trick.

Actually it's more like a downgrade! A Type C will take longer to react to an overcurrent than a Type B, which is why test need to be performed before the change.

 

[333rocky333]

Getting the mcb could be a chore, not sure what make you have, but Series E suggests possibly GE, steeple or sector, which I think were the same just branded different, but whether the current versions are still the same I don't know.

I note some one has fitted an MK one at the end which may again have been the same just rebranded, unfortunately that MK range has been superseded by a newer one that i'm sure is a different profile so MK proberly not an option.

A rated seller on ebay may be your only option.

 

[ban-all-sheds]

Some snippets from the conversation with a transformer manufacturer about the design of a bespoke transformer for a lighting installation of 372 incandescent 2 watt lamps at my daughter's wedding.

Did you need them to all come on at once?

 

[bernardgreen]

Did you need them to all come on at once?

Each string of 31 lamps had its own switch and fuse on a panel of the transformer housing so that they could be powered up in sequence if necessary ( belt and braces ) . The careful design of the transformer ( by the manufacturer's designer ) meant that the mains supply to the transformer could be switched ON with all lamps on load.

 

[ban-all-sheds]

I just wondered if sequenced switching could have meant a set of smaller OTS transformers and no need for anything custom.

You could have replaced the fun-quotient of having a custom transformer with building something to automate the powering up

 

[bernardgreen]

a set of smaller OTS transformers

would had a larger in rush than the custom built and by the time all the mains voltage switching, fusing and mechanical mounting of the transformers had been added the cost of the single custom was only a few % more expensive than 6 or 12 off the shelf transformers. The ELV fusing would still be needed.

 

[ban-all-sheds]

OK