Blue Spark at Light Switch

[Tintern]

Can anyone help? I've recently installed low voltage lights and a new light switch. The low voltage lights did not need to be earthed, however I have now noticed that the light switch has a visible blue spark when you turn the switch on/off. An electrician recently replaced the switch and now I am unsure as to what the problem is????? Any ideas????

 

[ricicle]

The load could now be too great for the switch - what is it's rating?

If the low voltage lights are powered via a wire wound transformer the inductive nature of this can cause arcing when switched.

Is the switch of a renouned brand?

 

[Tintern]

According to the Wickes instructions no transformer was required. The double switch should take up to 1000w and there is less than 850 in total. 450 on one switch and 400 on the other.

 

[RF Lighting]

I've recently installed low voltage lights and a new light switch. The low voltage lights did not need to be earthed

no transformer was required

Make your mind up

 

[Adam_151]

We could be so used to the term LV being applied wrongly, that the one time someone uses it correctly we get all confused and arn't sure what to make of the situation

 

[Tintern]

I'm not sure what you mean by saying make up your mind.....

The switch gives off a blue spark, (this has only occurred after installing low voltage lighting - with no transformer) The switch was changed - not to any special brand but it is white plastic and not metal. I'm increasingly becoming more anxious that it could be dangerous to either me or someone else.

 

[JohnD]

a good quality light switch by Crabtree, MK or MEM will be rated at 10A, which should be plenty. Cheaper light switches may not be as good.

If you have low-voltage lamps (like 12v) then they must either have an integral transformer, or a separate transformer, since you are supplying them from a 230v circuit.

Electricians use the term "low voltage" to mean something else, they call 12v lamps "extra-low voltage" but we think that you are referring to 12v lamps or thereabouts.

If the switch is mounted in a metal back-box which is properly earthed to the lighting circuit, it is unlikely to be able to give anyone a shock, even if it becomes faulty.

 

[briwire]

If they are low voltage, a transformer must be used. As stated, a spark is produced when an inductor, such as a transformer is turned off. Don't worry about it.

 

[securespark]

I'm a tad worried when you mentioned the switches having wattage limits.

Are they dimmers?

What kind of lamps are fitted?

 

[ban-all-sheds]

I'm not sure what you mean by saying make up your mind......

The reason is that the term "low voltage" is used differently by electricians to everyone else (including most manufacturers and retailers of 12V lighting products).

The IEC definitions of voltage bands are:

• Extra Low Voltage: AC below 50V and DC below 120V
• Low Voltage: 50 - 1000V AC or 120 - 1500V DC
• Medium voltage: 1kV - 35kV
• High voltage: 35kV - 230kV
• Extra-high voltage: >230kV

So "low voltage" is what the mains supply to your house is, but when you talk about "low voltage lighting" we know you mean 12V. I suspect the reason the instructions say no transformer is required is because one is integral to the light you've bought...

 

[Steve]

Dont worry about a blue spark. Its normal. Even the MEM switches at work spark, they have about 700 watts of fluorescent lighting on each though.

 

[sparkydude]

That is a very stupid thing to say , just because your switch sparks does not mean its right, Switches should not spark ansd if they do they are probably overloaded and not rated for the load applied to them. Your switches with flourescent s on them are obviously not 20A rated as that is what is normally recommended to cope with the starting current of the lights.

Nick

 

[bluesparkydude]

i get everywhere, me.