One FCU, 2-gang switch for two sets of lamps

Hi there,

Following my recent success at installing some porch lights off an FCU, the missus now decides that she wants the porch on the side of the house doing in the same way. Why she couldn't have told me this before, I have absolutely no idea... but I digress.

Anyway, because of the layout of the house, it'd actually be more convenient to amend the existing front porch lights layout in some way, rather than create a separate spur etc.

At present, the front porch lights use the FCU as their functional switch. However, she now wants the front and side porch to have their own independent switch. I don't like the idea of sticking another FCU in, so is it possible for me to use a 2-gang switch (coming off the single FCU) to control the two sets of porch lights?

I'm assuming this is OK?

Both porches have similar cable lengths, similar PIR switching capacity and a similar total demand (105w or 0.43 amps).

If this is acceptable, could somebody take a look at the switching diagram I've drawn below and tell me if it's correct? I've deduced the layout from other threads but would prefer someone more experienced to give me the nod... or cruelly mock me.

Thanks,
W

That will work.

Is the FCU really part of a ring or should it be shown as a spur ?

Do you really want to have a double switch ? It's more common to have the switch adjacent to the area it covers, as a double it means the side porch switch will be remote from the area it covers- although I accept the PIR will do the main on / off via routine time and light setting.

TE isn't external cable, how will you route it ?

Great, thanks for your perusal. It is appreciated.

In answer to your question: the main feed is currently a spur, but given the ease of access to the void, I'm thinking about re-wiring a stretch and build it into the ring. No great shakes.

I take your point about switch location (I anticipated someone might say that), but the layout of the house means that the switch is fairly central between the two doors. Hard to explain without a diagram. And as you say, the PIR switches as soon as the door is opened.

Routing of 1.0 T&E will be mostly via under the floorboards of the first floor. Getting there is not a problem as the hall will be skimmed with plaster at a later date.

Incidentally, is it preferable to conduit (under the plaster) as much as possible? I noticed that all the lighting cables in the house run down elliptical metal tubing that protects them from stray nails being driven into the wall (which I would have thought needed earthing, but doesn't appear to be).

If so, is there a particular type/brand of conduit that is industry-standard?

tambourineman said:

Untitled

• tambourineman
• 20 Oct 2010
• 2

Click to expand...

Are you aware that you could use a 3-module grid, with 1 fuse and 2 switch modules?

tambourineman said:

Incidentally, is it preferable to conduit (under the plaster) as much as possible? I noticed that all the lighting cables in the house run down elliptical metal tubing that protects them from stray nails being driven into the wall (which I would have thought needed earthing, but doesn't appear to be).

If so, is there a particular type/brand of conduit that is industry-standard?

Click to expand...

If the cables are in a safe zone they don't need mechanical protection. PVC conduit doesn't provide that but can be used to make future changes easier. Bear in mind that you'll need deeper chases.

If you want metal conduit this is the stuff:





Don't buy from TLC though - you can get galvanised elsewhere for less than they charge for black enamel....

Thanks for the reply, BAS.

Grid would be nice (reading about them in another thread), but the missus is insistent on matching metalwork style throughout. She bought into a particular range, and they don't do grids. I'll have to find an excuse to use one somewhere tho!

Regarding the metal conduit:

What's deemed a 'safe zone' (or an 'unsafe zone' for that matter)?

Cheers
W

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

Useful.

Again, thanks for your time and direction.