Intermediate Switch(es) Required?

[dpm_dpmartin]

Lets hope the wiring remains in a safe zone

I do not know what this means... I have now ordered my stuff, could I come a cropper for some reason I don't get?

 

[ban-all-sheds]

If you have concealed cables running vertically to a switch, you can't just remove the switch, as that will remove the zone where you are allowed to have concealed cables.

//www.diynot.com/wiki/electrics:walls


But I've lost track of what you decided to do. If you're going to end up with a double-wide switch you'll probably be fine. If you're replacing the 2 single-width ones with 1 single-width you could well not be.

You need to find out where the cables run.

 

[dpm_dpmartin]

I am going [have gone] for a single-width 3-gang modular switch - 2 of them will be 2-ways and 1 will be intermediate - I will take the intermediate modular bit from the back of the existing intermediate switch on the wall.

I wanted to end up with a single switch plate on the wall with 3 switches, not 2 side-by-side or an [unnecessary?] double-wide.

 

[dpm_dpmartin]

Is it likely that 2 light switches - that sit side-by-side on the same wall - would be in a different 'zone'?

Forgive me asking with probably incorrect terminology... but that seems a bit strange (to me).

All this detail makes me really nervous about the Electrician I was talking to - who had the situation explained to him but didn't seem to consider it any kind of issue, very flippant about it - "I'll just make it work"..!

 

[JohnW2]

Is it likely that 2 light switches - that sit side-by-side on the same wall - would be in a different 'zone'? ... Forgive me asking with probably incorrect terminology... but that seems a bit strange (to me).

If I understand correctly (that you intend to replace the current pair of single-width switches with one single-width switch), then there could possibly be a problem - it depends on where the cable enters the back boxes of the current two switches.

Buried cables are required to travel in 'safe zones', which are vertically (or horizontally) in line with accessories such as switches, and equal in width to the accessory. With you new proposed arrangement, the position of one or more of the cables (which I imagine travel vertically in the wall) may not be within the width of the new, sole, single switch, and therefore not in the new (narrower) 'safe zone'.

Kind Regards, John

 

[dpm_dpmartin]

If I understand correctly (that you intend to replace the current pair of single-width switches with one single-width switch), then there could possibly be a problem - it depends on where the cable enters the back boxes of the current two switches.

Yes, this is the correct understanding of my aim.

So, I suppose I will not know until I get a screwdriver and have a look-see. My confusion arises when I think about the fact that they're all light switches - controlling lights on the same floor, floor below and floor above... what reason could there be for different 'zones'?

Can I not just 'jump' the cable that, I presume, is going to be in the 'zone' above one of the switches into the zone to where the single single-width switch I want to have is going to be? Then all 3 end up in the same 'zone'?

These switches - you can see - are side-by-side with no gap between - does that imply that the 2 zones we suspect are running vertically, taking up the same space as the accessory, are effectively 1 big fat zone?

I know you can't answer until I open it up... but I don't know if I'll be able to tell once I've opened it up even. Won't I just see some kind of backbox and a load of wires coming out of the wall?

More challenging than I ever thought, this.

 

[ban-all-sheds]

Basically if you have A or B you'll be OK, C will mean moving cable(s) across.

Just look at the drawings in the Wiki article.

 

[dpm_dpmartin]

Thanks, yes, I do get the concept of zones now.

My question is - if the zone is understood to be the same width as the accessory it pertains to, then isn't C effectively showing a single big fat (wide) zone, as the accessories are demonstrably right next to each other?

 

[ban-all-sheds]

Yes, but you are going to be halving the width of the zone when you remove one switch.

 

[JohnW2]

Yes, this is the correct understanding of my aim. ... So, I suppose I will not know until I get a screwdriver and have a look-see. My confusion arises when I think about the fact that they're all light switches - controlling lights on the same floor, floor below and floor above... what reason could there be for different 'zones'? Can I not just 'jump' the cable that, I presume, is going to be in the 'zone' above one of the switches into the zone to where the single single-width switch I want to have is going to be? Then all 3 end up in the same 'zone'? .. These switches - you can see - are side-by-side with no gap between - does that imply that the 2 zones we suspect are running vertically, taking up the same space as the accessory, are effectively 1 big fat zone?

The point is that it is the switches themselves which create the zones (blue in the below) (just one cable per existing switch shown for simplicity):

Untitled

• JohnW2
• 30 Oct 2014
• 1

I've illustrated two possible situations in which (if buried cables remained in their present places) most of one, or both, of two cables would be outside of the new (narrower) safe one created by the new single switch.

Kind Regards, John

 

[dpm_dpmartin]

I think I really do get it now... a zone is not necessarily equal to a physical channel (air gap) that exists for the wires to run along, a zone is more of a concept that is defined by the width of the accessory itself, that says - inbetween the left and right boundaries of this accessory is where a cable could be, so be very careful (safe) if you're thinking of doing anything around that area, e.g. hanging a picture or what-have-you.

If I found out that the cables were situated as in your New (2) image, then someone (even me) could come along later and say "oh, I'll just drill here, to the right of this switch as I'll be avoiding the safe zone..."...and bam!

And, most importantly, by removing a physical switch, I also remove a safe zone!

 

[JohnW2]

I think I really do get it now... a zone is not necessarily equal to a physical channel (air gap) that exists for the wires to run along, a zone is more of a concept that is defined by the width of the accessory itself, that says - inbetween the left and right boundaries of this accessory is where a cable could be, so be very careful (safe) if you're thinking of doing anything around that area, e.g. hanging a picture or what-have-you.

Exactly.

If I found out that the cables were situated as in your New (2) image, then someone (even me) could come along later and say "oh, I'll just drill here, to the right of this switch as I'll be avoiding the safe zone..."...and bam!

Exactly.

And, most importantly, by removing a physical switch, I also remove a safe zone!

Exactly.

You are now pretty well-informed about safe zones It remains for you to discover where the cables to the existing switches actually run - you might just be lucky, but I certainly wouldn't put much money on it!

Kind Regards, John

 

[333rocky333]

sorry i brought it up but it is important.
personally, its highly likely they all come down above the right hand switch and on finding he couldnt get the "custom" switch, simply shunted that extra box to the side, i would have thought it easier to come down in one wide chase rather than two, though its not unknown for the cable to jump over to the left box within the last few inches and into the top.
im quessing it could be a bit "Busy" inside them switches so be carefull if you opt to look inside
You still have a whole width box to play with and likely you can cover the width even if there was two chases centred to the two, if that makes sense

 

[ban-all-sheds]

Or if defeat has to be admitted, a 3-gang switch on a double-wide plate doesn't look too bad.

In fact it can have advantages - more wiring space, and if it's a switch that might be operated in a half-awake state, easier to get the right rocker when fumbling in the dark.

 

[dpm_dpmartin]

I've ordered the thing I've ordered already, but I do like the look of that and it may be a back up... can I stick modular gubbins in the back of that? What is it and where do I get it (if I need it)?

It seems to have the brushed look and the nice curved edges of most of my existing stuff. The Click Deco stuff appears to have a harder edge.