Moving switch fro one side of door to the other.

[ringer]

Customer has asked me to move a light switch from one side of a bedroom door to the other. The door has been rehung so now the hinges are on same side as light switch and the switch is behind the door. There is no RCD protection at all in the house and it is a Victorian property so likely to be lath & plaster construction for internal walls. Am assuming cable comes directly from ceiling down to existing position of switch. Am also assuming if I re-route cable across top of door then the cable will be out of zones (zones being 150mm from corners and ceilings) and no longer vertical, so circuit would then need RCD protection. Can I re-route the cable along the top of the wall (within 150mm from ceiling) and then vertically down to the new position without adding RCD protection? I have no idea at this point (verbal instruction only) about whether access will be possible from the loft.

 

[pushrod]

Interesting -so are you saying that you would extend and surface mount the new cable to avoid the need for an rcd? I would think that was ok, unless anyone knows better. If access to loft is possible might be neater, if the customer was agreeable to just have a cord pull.
Personally i'd just re-hang the door

 

[Hawk81]

The short answer is No you can not install this cable without RCD protection. Page 60 in the OSG states:-
A cable concealed in a wall or partition must:
i be at least 50mm from the surface,
ii have an earthed armouring or an earthed metal sheath,
iii be enclosed in earthed steel conduit or trunking
v be installed either horizontally within 150mm of the top of the wall or partition or vertically within 150mm of the angle formed by two walls, or run horizontally or vertically to an accessory or consumer unit.

In domestic and similar installations, cables not installed as per i, ii, iii but in complying with v shall be protected by a 30mA RCD.


I hope this clears that up for you.
I never thought you might be surface mounting this cable if so then i would say that there was no need for RCD protection

 

[martysparky]

Why don't you RCBO as your altering. Explain the features and benefits of additional protection and they may want more.

 

[ringer]

Re: Moving switch from one side of door to the other.

Customer has stated no surface trunking - cables must be buried. So it looks like I have two choices:
1. run vertically from ceiling to switch, buried in wall with earthed metal capping (complying with iv) (you didn't mention option iv, Hawk)
2. run vertically from ceiling to switch, buried in wall and RCD the whole lighting circuit.
(using swa would possibly be another choice, complying with ii)

I'm not sure the customer will stand the cost of the RCD option, so it looks like metal capping, or possibly metal conduit.

I take it I can use the existing cable (presumably old colours) to do this if it will reach?

The thing is, I will not be installing a new circuit or cable, and the safety of the installation will not be less than it was before, so even the metal capping seems a bit OTT. I will comply with the regs, I am just questioning how far we should take them.

 

[Hawk81]

Re: Moving switch from one side of door to the other.

I know I did not mention iv as it was too much typing for something I was not even going to be thanked for. Well you know your options now anyway.

 

[Des 56]

You could do away with fixed wiring the new switch
Fit a reciever and wall mount a radio operated switch

 

[ringer]

You could do away with fixed wiring the new switch
Fit a reciever and wall mount a radio operated switch

Where would I get that from Des, and how much?
I did look at a similar setup using PIR for another customer but it was upwards of £50 materials.

 

[telectrix]

if wall is lath and plaster, could you not drop cable inside wall, 50mm away from surface, hence no need for RCD.in the cavity of the studded wall. only deviation would be cable not adequately supported.

 

[ringer]

Have been looking a bit further into this, and it seems a lot of people are of the opinion that metal capping does not provide sufficient mechanical protection against a nail or a drill. So I'm left with either conduit (probably too bulky to hide under plaster) or Telectrix's suggestion of running down the cavity. Customer is disabled man and wife is full time carer - money is very tight - have already agreed to drop my hourly rate for them - pretty sure they cannot afford to pay for enclosures and RCDs.

 

[telectrix]

if it's lath and plaster, you don't want to even attempt to chase. the lath and plaster construction is not meant to be chased. even worse than trying in plasterboard. another possibility is a pull switch in the ceiling.

 

[Amp David]

If lath and plaster and no nogging on the route of the switch drop, then drop a length a steel conduit doen to the switch and get it earthed, job done, no RCD/RCBO required.

All depends on the customer and how much they all willing to spend. I know which route i'd be taking if they were lets say 'on a budget'!

 

[telectrix]

regarding earthing of said conduit..... does it have to be earthed back to the CU or MET, or can it rely on the cpc of the circuit through the K/O box? all i can find in the regs. is trhat the conduit must be earthed.

 

[Des 56]

My veiw would be, it wont have to carry any greater fault current than the cicuit it is used for,so the same size cpc as the circuit it is protecting using that earth path

 

[telectrix]

My veiw would be, it wont have to carry any greater fault current than the cicuit it is used for,so the same size cpc as the circuit it is protecting using that earth path

so, in effect, it can be earthed through the K/O box as long as said box is bonded to the cpc in the conduit. ( or, if using a dry lining box, clamp cpc fly lead to conduit.)

 

[miner69er]

in my humble opinion, fit an rcd fcu next to the board and run the lighting cable through it. these things are only £25 and it saves loads of hassle trying to work around the regs.....