Understairs light and push to break swith or PIR

[JohnW2]

Door switches only have 2 terminals, there is nowhere to connect any earth, and it would be entirely pointless using 3 core cable for them, assuming you could actually get the larger 3 core cable to fit into them.

Entirely pointless, I agree, so no problem if one is happy being non-compliant with 411.3.1.1 of BS7671.

I wonder how Mr Jobsworth (particularly Mr post-PRS-legislation Jobsworth) would code this on an EICR?

Kind Regards, John

 

[JohnD]

Most switches have an earth connection, and T&E or 3 core cable would be used, either connected to the switch itself or the box it's fixed to.

Door switches only have 2 terminals, there is nowhere to connect any earth, and it would be entirely pointless using 3 core cable for them, assuming you could actually get the larger 3 core cable to fit into them.

1) I've seen the diagram, where the supply comes from a junction box or something, with an earthing terminal.

2) At any point, from today onwards, a person might decide to fit an ordinary switch and remove the current one. Or fit a nice metal wall lamp.

 

[dazzler9000]

Okay chaps, so what are we saying, don't use the two core switches?

 

[flameport]

I wonder how Mr Jobsworth (particularly Mr post-PRS-legislation Jobsworth) would code this on an EICR?

Doubtful they would even notice, as most EICRs these days appear to be done like this:

non-compliant with 411.3.1.1

It's a departure, but one that doesn't compromise safety in any way, and the alternative is a cable with the earth wire cut off at the door switch which is worse.

2) At any point, from today onwards, a person might decide to fit an ordinary switch and remove the current one. Or fit a nice metal wall lamp.

Other persons could do anything at any time. Absolutely nothing that anyone today can do about it, and whatever is installed now could easily be turned into a dangerous mess by future buffoons.

 

[JohnD]

I'm sure you been in places where people have snipped off earth wires.

 

[JohnW2]

Okay chaps, so what are we saying, don't use the two core switches?

I don't thing tht anyone is suggesting that. The only question is whether one should use 2-core (rather than 2-core + earth) cable.

As flameport said (and I agreed) with things as they are (will be when you've done it), to have an earth run to the switch would be 'pointless' - and would present a problem of 'what to do with the earth' at the switch end.

However, as I said, the regulations theoretically require an earth to be run to 'every point in the wiring and every accessory' - as JohnD has indicated, presumably 'in case' the present switch (which does not require, and has no provision for, an earth) is, as some future time, replaced with something which does require an earth.

I think many, maybe even most, people would do as flameport suggested and 'ignore' that regulation in your case - but it's only right that you should at least be made aware that it would, theoretically, be 'non-conformant' with the regulations not to have an earth.

Kind Regards, John

 

[JohnW2]

It's a departure, but one that doesn't compromise safety in any way, and the alternative is a cable with the earth wire cut off at the door switch which is worse.

I agree. Indeed, I should have talked about non-compliance since, per 18th ed. a non-conformity which does not present a danger is not a non-compliance'. However, as I've justr written, I think the OP should at least be made aware of the fact that it is, technically, non-conformant to have no earth.

Other persons could do anything at any time. Absolutely nothing that anyone today can do about it, and whatever is installed now could easily be turned into a dangerous mess by future buffoons.

Agreed, and that's an oft-discussed point. It does, however, a good few of the regulations seem to exist in anticipation of what buffoons might do in the future - so do you think it's acceptable top ignore all of them?

Kind Regards, John

 

[dazzler9000]

I see this thread has sparked a bit of debate. So just to summarise for a non-electrician, I think what you're saying is....

I have no choice but to use 2 core as the switches don't support the use of an earth cable (I'm assuming this is because they are plastic and don't need one) and are perfectly safe? The debate is whether to use 3 core and snipping off the earth, this seems to be frowned upon due to the fact that these wires could be used by someone at some point with a metal switch that requires an earth but the user might not know this (same applies to using 2 core) and could pose a safety risk.

So just to be clear, I'm not moving and this will be a forever home, so not really an issue. This brings me on to another question. Flameport kindly recommended "2 core flat 0.75mm²" cable. I always thought the lighting circuit needed to be 1.5mm. Have I got this wrong?

 

[JohnW2]

... This brings me on to another question. Flame kindly recommended "2 core flat 0.75mm²" cable. I always thought the lighting circuit needed to be 1.5mm. Have I got this wrong?

Lighting circuits are actually allowed to use 1.0mm² cable, but that only applies to 'twin and earth' (i.e. 'house wiring') cables, and not flexible cables (I don't think it's meant to make sense ). Flat 0.75mm² flexible cable is therefore 'allowed' .

Kind Regards, John