Voltage detector question

[Kevinjm]

After fitting a new light switch I thought I would try my voltage detector pen around the switch only to find it picks up a current when I touch the actual switch is this because it's metal and just picking up the switch behind it or could it be something wrong ?

 

[ericmark]

Every make of detector is different in fact even two identical looking units can behave different. The reed switches are easy damaged and we often rub on our cloths to test it still works. Be is a voltage detector using a reed switch or a neon screwdriver they are handy tools but they are not test equipment.

So in your case with a plastic switch I would expect it to light on the switch. With a metal switch with earth wires correctly connected I would not expect to to work in centre of metal plate and would remove switch and test the earth wire again to ensure the earth is actually connected.

Before 1960 many lights were not earthed but as we started to use metal lamps and switches the rules changed and now lamps and switches must have an earth wire even if not connected due to using class II fittings. But where some alterations have been made it is common to find an earth wire which is not actually connected to anything. So testing is an essential part when swapping from class II to class I equipment.

So it may be OK but it alerts one to re-test using proper test equipment.

 

[Kevinjm]

This is the switch so earth goes to the switch then earthed to box via screws I presume

 

[Kevinjm]

Switch used

• Kevinjm
• 3 Feb 2015
• 1

 

[bernardgreen]

Is that a piece of wire connecting the two rivets together,

Not good as over time the rivet's grip on wire and front plate is likely to become loose over time and then the earth connection to the front plate may fail.

Is the CE mark genuine ?

 

[JohnW2]

Not good as over time the rivet's grip on wire and front plate is likely to become loose over time and then the earth connection to the front plate may fail.

Not really an issue, given:

... earth goes to the switch then earthed to box via screws I presume

However, having the back box's earthing reliant on the faceplate screws is obviously not very satisfactory, since the back box then ends up unearthed when the screws are withdrawn - but that's something that a short length of wire would easily cure,

Kind Regards, John

 

[Kevinjm]

Was bought from screwfix so presume its a pucker part not dodgy knockoff !

 

[delmel]

screwfix often selling bottom of the range products imported from an unbranded source in china. However most switches come from China now.