Increasing lighting circuit MCB ampage

[bernardgreen]

Does it trip at switch on, at switch off or at random when the light is on ?

Is there just one switch or are there two switches controlling the light ?

 

[sunningdalelad]

Does it trip at switch on, at switch off or at random when the light is on ?

Is there just one switch or are there two switches controlling the light ?

Only trips at switch on, there is only one switch.

 

[bernardgreen]

What does the transformer look like ?

Is a real transformer ( often round shape ) or an electronic one ? ( rectangular box or tube shaped ).

 

[sunningdalelad]

What does the transformer look like ?

Is a real transformer ( often round shape ) or an electronic one ? ( rectangular box or tube shaped ).

It is round and foil wrapped.

 

[bernardgreen]

Sounds like a toroidal then ( a bit like a dough nut ).

These do have a high in-rush current. But they are the best type of transformers ( nothing t ogo wrong in them ) but do have the problem of tripping fast operating MCB at switch on.

I will have a word with a "man who knows"

 

[RF Lighting]

If the inrush current is great enough to trip a 6A type C MCB then there is a real risk of it also welding the switch closed.

 

[Taylortwocities]

As an off the wall suggestion. Try fitting a 500watt IQ dimmer. These have a soft start feature so the light comes on over about 1 second - should reduce the surge.
Here's one http://www.tlc-direct.co.uk/Products/VLQP501.html

 

[sunningdalelad]

As an off the wall suggestion. Try fitting a 500watt IQ dimmer. These have a soft start feature so the light comes on over about 1 second - should reduce the surge.
Here's one http://www.tlc-direct.co.uk/Products/VLQP501.html[/QUOTE]

Having viewed the IQ dimmer through the above link this seems to be a logical solution. Will wait and see what bernardgreen's contact says then tackle the issue. Thanks.

 

[bernardgreen]

Not good news unfortunately for a domestic situation

<<edit>> The dimmer solution just mentioned may be a way to go if the dimmer has built in current limiting which many good one do have ( but not the cheap ones ) <<|>>.

He doesn't know the details of the transformer involved but he has dealt with a similar situation by fitting current limiting surge suppressors.

These devices are high resistance when cold and low resistance when hot. Putting one of these in series with the transformer limits the current until the device heats up and allows almost the full current to flow. This prevents the inrush current that trips the MCB. BUT this means there is a small but hot component in the circuit that has to be safely installed. He had these devices mounted in metal back boxes with a blank face plate next to the switches.

Ametherm Inrush Current Limiters
http://www.ametherm.com/Inrush_Current/welcome.html


The other option would be to buy a zero volt switching solid state device to control the power to the transformer. This will connect the power when the mains is at the zero volt point which significantly reduces the inrush current. These maybe available as a standard switch plate but I haven't seen one.

For a large motor load I used a zero volt switching relay to connect the motor to the supply. The switch on the wall switched power as switched live to the relay "coil" and via the relay contact to the motor. The relay operated when the AC mains was at the zero volt point so the motor in-rush current was low.

 

[sunningdalelad]

The Cat C MCB seems to be coping now, it has only tripped out twice. If it trips more frequently I will try the dimmer suggestion. If that fails maybe I'll move house. Thanks for everyone's help.

 

[chris_1982]

After reading this topic, i cant believe that this light you have trips a 6a mcb. Personally i've never encountered a domestic light fitting to do this. You certainly shouldn't have to change from a type b mcb.

 

[Taylortwocities]

Chris, I've seen quite a number of lights of this type do just this. Have a read thru the thread & you'll see why its happening. but I agree with your latter comment re not changing the mcb.

 

[sunningdalelad]

After reading this topic, i cant believe that this light you have trips a 6a mcb. Personally i've never encountered a domestic light fitting to do this. You certainly shouldn't have to change from a type b mcb.

It surprised me and I would have expected a warning in the fitting instructions. However the technical department at Endon advised me of this. Has any electrician out there fitted a light fitting from Endon with 12 x 20 watt low voltage halogens and a transformer without the need to replace the cat B 6A MCB.

 

[chris_1982]

It surprised me and I would have expected a warning in the fitting instructions. However the technical department at Endon advised me of this.

They advised you it may trip it out? Thats crazy.

 

[sunningdalelad]

It surprised me and I would have expected a warning in the fitting instructions. However the technical department at Endon advised me of this.

They advised you it may trip it out? Thats crazy.

This is the e mail response from Endon

"This is a common characteristic of this type of transformer; a toroid.

Usually the electrician sorts them out so we don’t put advice in the fitting instructions.

In 99% of the cases a type C breaker sorts out the problem, a type D which I understand has a longer delay should certainly cure the tripping."