200W Low Voltage Toroidal lighting problem

[king.inter]

Hello all, So heres the problem. My partner has bought a low voltage ceiling light which holds 10x 20Watt halogen bulbs poewered by its own built in toroidal transformer. I did the 10 minute job of fitting the light as a direct replacement for the old pendant, tested the light & on it came, no problems. Now if I switch it on and off a few times (not fast) it eventually trips. It also trips sometimes on the first switch on. There are obviously other lights on the ring, but none are turned on while testing this one.

The consumer unit is a "Square D" Quikline.

The mcb that the lighting circuit is connected to is a "C6" Can anyone help me on this?
Should I run it from its own free slot in the consumer unit? or is there an easier way out?

I'm positive that the wires are all in the right places & the light switch is a stainless steel \ hidden screws \ crabtree. (Not dimmable)

 

[Steve]

a C6 shouldn't trip. Those transformers do soak up some startup current, enough to trip a B6 sometimes, but it should never trip a C6, since C6 are designed to hold up on lamp failure and heavy fluorescent startups.

Is the light just on a normal switch? No dimmer?

 

[mo2]

I'm positive that the wires are all in the right places & the light switch is a stainless steel \ hidden screws \ crabtree. (Not dimmable)

Is the light just on a normal switch? No dimmer?

 

[king.inter]

No dimmer

 

[king.inter]

Thought this might have been an easy one

Just an update, it is obviously something to do with the power surge upon turning on the lights. You can hear the MCB "Trying" to trip when it doesn't actually go off.

What would fitting a 10A MCB achieve?

I've also been told about a "motor breaker" (No car jokes please)
Which is supposed to give it a gentle start

Any advice?

 

[RF Lighting]

I've also been told about a "motor breaker" (No car jokes please)
Which is supposed to give it a gentle start

Any advice?

I have seen this exact problem and I cured it fitting a motor rated (or type C) MCB.

The only problem is that you already have this fitted.

Only thing I can think is to try replace the MCB for another 6A type C, and if this doesn't work, a 10A type C might be the answer, but before you do this you must get an electrician to make sure the new MCB will provide the circuit with the correct level of protection.

Get him to make sure that the cable is big enough, and the Zs is low enough. It should be below 1.92 ohms.

 

[Steve]

One thing: should the OP have to do all this to make his light work on a standard UK lighting circuit?

 

[king.inter]

I've also been told about a "motor breaker" (No car jokes please)
Which is supposed to give it a gentle start

Any advice?

I have seen this exact problem and I cured it fitting a motor rated (or type C) MCB.

The only problem is that you already have this fitted.

Only thing I can think is to try replace the MCB for another 6A type C, and if this doesn't work, a 10A type C might be the answer, but before you do this you must get an electrician to make sure the new MCB will provide the circuit with the correct level of protection.

Get him to make sure that the cable is big enough, and the Zs is low enough. It should be below 1.92 ohms.

Can't I measure the ohms? I'm no electrician, but I've got common sense. The cable looks like 1 mm2 or 1.5mm2

 

[baldelectrician]

the Zs is a reading (earth loop impedance) that is done LIVE using specific test equipment, it can't be done with a basic meter.

Having a good earth is important, or adequate RCD protection if the earth is poor, testing is required to establish the exact situation and requirements.

Another thought-

If you had a suited dimmer (rated for torriodal trannys and 200w) there should be a soft start, thus helping prevent the MCB tripping.

 

[king.inter]

Swapped the C6 for another one in the box - Same problem.

Can you suggest any dimmers for a toroidal? I'd like to keep the crabtree range if possible.

 

[Steve]

http://www.tlc-direct.co.uk/Products/VLIC1701.html

i have one of these, very good piece of kit. Get the 600w one, gives plenty of headroom for not a lot of extra cost. And you can programme one of the buttons on your TV remote to control it

Basically, you touch it once and the light "dims" on, it doesn't just come straight on, takes maybe half a second to come on full brightness. This is the "soft start" in action. Though i believe the switch works differently for different types of transformer and load. It is self protecting too, so if it simply cannot control your light fitting, it will not apply power to it.

Available at B&Q and all "good" DIY sheds.

 

[king.inter]

Ok, I have ordered one of these IQ 600W touch dimmers. It looks as if it could solve the problem. Will let you guys know what happens after its fitted. Fingers crossed ehh....

 

[king.inter]

http://www.tlc-direct.co.uk/Products/VLIC1701.html

i have one of these, very good piece of kit. Get the 600w one, gives plenty of headroom for not a lot of extra cost. And you can programme one of the buttons on your TV remote to control it

Basically, you touch it once and the light "dims" on, it doesn't just come straight on, takes maybe half a second to come on full brightness. This is the "soft start" in action. Though i believe the switch works differently for different types of transformer and load. It is self protecting too, so if it simply cannot control your light fitting, it will not apply power to it.

Available at B&Q and all "good" DIY sheds.

Right, I got one of the above dimmers as suggested and it does work, BUT it says in the instructions that it is not to be used with a toroidal transformer. It works as it is supposed to, emmits a buzzing sound while on. Am I to keep using this, or is it unsafe?? I'm baffled, I mean all I want to to is put the light on without the thing tripping. Do I need to to exchange the switch for a manual IQ dimmer? If so, can anyone point me in the right direction on the TLC website.

200Watt built in toroidal transformer
12V Low voltage

 

[king.inter]

http://www.darlighting.co.uk/products.php?c=any&itemTYPE=329

AMADEUS 10LT LV SEMI FLUSH C/W BULBS

About half way down the page

 

[Steve]

USES FOR THE SWITCH

Your VARILIGHT intelligent safety dimmer is suitable for: mains voltage GLS bulbs; mains voltage halogen bulbs; fans; most electronic transformers (including those requiring trailing-edge control) and toroidal transformers.

now as far as i can tell, that site is a direct copy of the varilight instructions. If it is misleading, and your instructions do, in fact, say it is NOT suitable for toroidal tx's you will be entitled to a refund, its mis-selling.

Are you absolutely sure it is a toroidal tx? I just dug out the instructions for my dimmer, and it does, in fact, say, not suitable for toroidal tx's but it also says

"If a transformer appears as a highly inductive load, eg. wire wound or toroidal transformers, the dimmer will not work. To protect itself it will turn off within one second. The dimmer will allow this to happen 3 times before blocking further use until it is disconnected and reconnected to the mains electricity."