Crescendo style LED lighting on stairs - connect via Lighting or Sockets circuit?

[DaveFix]

I'm going to install one of those stair lighting systems where a controller illuminates each step, about ½ second apart, once triggered by a PIR sensor. The controller will be powered by a 24v transformer, and I'll be installing a mains switch for it.

Which circuit should this be connected to - lighting or sockets? I have the ceiling off and easy access to both.

 

[Taylortwocities]

Either, but if you go for the sockets circuit you’ll need to feed the lights via a fused connection unit with a 3amp fuse in it.

Feed off the lighting circuit would be better. No fuse needed.

 

[JohnW2]

Either, but if you go for the sockets circuit you’ll need to feed the lights via a fused connection unit with a 3amp fuse in it.

... or, of course, feed via a "13A plug/socket" (with an appropriate plug fuse) !

Feed off the lighting circuit would be better. No fuse needed.

Agreed.

However, to be a bit more serious, although the OP tells us that, at present ...

I have the ceiling off and easy access to both.

... even if he uses the lighting circuit he presumably would not want to hard-wire it directly to somewhere above the ceiling (which presumably won't be "off" when his fancy lights {inevitably!} go wrong at some point in the future) - so he'll probably want/need to have some sort of accessible socket/ switch/ FCU/ whatever even if it's fed from a lighting circuit?

Kind Regards, John

 

[DaveFix]

I have the ceiling off and easy access to both.

By that I meant that I currently have easy access to both the lighting and socket circuits, so I can spur off either.

The controller, transformer and mains outlet will be in a cupboard under the stairs, so they can be changed over the years when the inevitable happens.



I think I'd prefer to use the 3amp fused connection unit, as I don't like to see permanently fixed devices connected with a plug.

Since either circuits are fine, I'll tap into the lighting so I don't have to power down some sensitive equipment on the sockets circuit.

Feed off the lighting circuit would be better. No fuse needed.

Would it be okay if I feed off the lighting circuit and also use a 3amp switched connection unit?

 

[bernardgreen]

Have you considered what effect this "moving" light source could have on someone using the stairs. If this cascading light is the only source of light on the stairs then the person may become confused / disoriented and potentially fall down the stairs.

 

[JohnW2]

The controller, transformer and mains outlet will be in a cupboard under the stairs, so they can be changed over the years when the inevitable happens.

Fair enough - that addresses the potential issue I raised.

I think I'd prefer to use the 3amp fused connection unit, as I don't like to see permanently fixed devices connected with a plug.
Since either circuits are fine, I'll tap into the lighting so I don't have to power down some sensitive equipment on the sockets circuit.

As has been said if you use the lighting circuit, you wouldn't need an addition fuse - so some sort of junction box, or maybe switch, would be perfectly OK as an alternative to an FCU.

Would it be okay if I feed off the lighting circuit and also use a 3amp switched connection unit?

Perfectly "OK" but, as above, unnecessary to have that extra fuse - a junction box or switch would suffice.

Kind Regards, John

 

[DaveFix]

Have you considered what effect this "moving" light source could have on someone using the stairs. If this cascading light is the only source of light on the stairs then the person may become confused / disoriented and potentially fall down the stairs.

It's not the only light source; there are some LED downlighters, and soon to be picture lights and possibly cove lighting. Actually the lights in the hall and landing come on automatically through occupancy sensors, so never even a need to fumble around in the dark for light switches, or balance a tea tray to switch them on and off.

As has been said if you use the lighting circuit, you wouldn't need an addition fuse - so some sort of junction box, or maybe switch, would be perfectly OK as an alternative to an FCU.

Just curious - what's the reason it would need a fuse if connected via the sockets circuit, but not need a fuse if connected via the lighting circuit?

 

[JohnW2]

Just curious - what's the reason it would need a fuse if connected via the sockets circuit, but not need a fuse if connected via the lighting circuit?

The lighting circuit will already have (nearly always 6A) protection from the MCB in your consumer unit, which is perfectly adequate. However, a sockets circuit will commonly only have 32A protection, far too high to adequately protect the sort of 'lighting wiring' you are contemplating.

Kind Regards, John

 

[Sureitsoff?]

Cue Winston saying that you cant put a socket on a lighting cct.....

 

[DaveFix]

The lighting circuit will already have (nearly always 6A) protection from the MCB in your consumer unit, which is perfectly adequate. However, a sockets circuit will commonly only have 32A protection, far too high to adequately protect the sort of 'lighting wiring' you are contemplating.

Ah that makes sense, thanks.

However, that's got me thinking: if the stair lighting controller - or more likely its transformer - develops a fault which trips the MCB, all the lights on that circuit (the downstairs) will go off, and it might be impossible to switch the MCB back on until the fault is identified and isolated which - depending on my age by then - could prove to be a rather unpleasant / costly / lengthy experience.

If the stair lighting transformer was connected via a 6amp fused connection unit: which would be expected to respond to a fault first, the 6amp fuse in the connection unit, the 6amp MCB, or the 80A 30ma RCD?

 

[Sureitsoff?]

hence the suggestions about feeding the stair controller via a plug and socket, if it develops a fault you unplug it and everything else still works.

 

[bernardgreen]

Cue Winston

i believe he has left the forum.

 

[JohnW2]

i believe he has left the forum.

If he has, that must be very recent - I think he posted earlier today, didn't he?

Kind Regards, John

 

[JohnW2]

Ah that makes sense, thanks.

You're welcome.

However, that's got me thinking: if the stair lighting controller - or more likely its transformer - develops a fault which trips the MCB, all the lights on that circuit (the downstairs) will go off, and it might be impossible to switch the MCB back on until the fault is identified and isolated which - depending on my age by then - could prove to be a rather unpleasant / costly / lengthy experience.

True, but equally true of any other fault in something connected to the lighting circuit. In any event, that why I suggested that it should be connected via an (accessible) junction box or, better, switch, so that you could disconnect just that one thing if necessary. It would be best to have a 'double pole' switch. Ironically, switched FCUs (the switch of which is invariably double-pole) are generally cheaper than DP switched - so you might end up with a switched FCU, anyway (despite it containing an unnecessary fuse!).

if the stair lighting transformer was connected via a 6amp fused connection unit: which would be expected to respond to a fault first, the 6amp fuse in the connection unit, the 6amp MCB, or the 80A 30ma RCD?

The answer is, unfortunately, that it would be anyone's guess! If the FCU had a 6A fuse, there's certainly no telling whether or not it would blow before the 6A MCB tripped- and the same would even be true if (as suggested), you had a 3A (or even 1A) fuse in the FCU - and if the fault were one which caused the RCD to trip, it's very unlikely that any fuse would stop that. However, switching off a DP switch (as such, or within an FCU) would enable to you reset the MCB and/or RCD in the event of a fault in the stair lighting.

Kind Regards, John

 

[DaveFix]

Thanks everyone, I've decided to tap into the sockets circuit and use a switched FCU inside the cupboard under the stairs. The main reasons for deciding this over the lighting circuit is because it leaves more options open for the future - I have concrete floors and a new ceiling will of course be going back on soon. For example, it creates a more accessible point if I ever needed to feed an additional socket, stair lift or whatever else the future brings.