Help with lighting layout

[gazdkw82]

Helping a friend out to finish the lighting that has been 1st fixed but the electrician has not returned and cannot be contacted.

I thought I had my head around it but then when they said they wanted dimmers it dawned on me that they may all require neutrals and now I'm doubting I have the right understanding of the wiring.

Iv attached a quick diagram of the cables that come into the box and the lighting layout.

Any help would be appreciated. Lighting isnt my strong point.

 

[Markyd]

Get a sparky

 

[telectrix]

Helping a friend out to finish the lighting that has been 1st fixed but the electrician has not returned and cannot be contacted.

I thought I had my head around it but then when they said they wanted dimmers it dawned on me that they may all require neutrals and now I'm doubting I have the right understanding of the wiring.

Iv attached a quick diagram of the cables that come into the box and the lighting layout.

Any help would be appreciated. Lighting isnt my strong point.

can't make it out from those pics. tryh and get them clearer.

 

[telectrix]

Get a sparky

not very helpful to a trainee who's trying to help a mate out.

 

[Markyd]

well get a sparky to help him do it and explain it to him

 

[Lucien Nunes]

Right. There are lots of permutations here; it's understandable and probably fixable but we need more info to decide how to tackle it.
1) Please confirm that the switch position with the spots cable is where the 3-gang dimmer is supposed to be.
2) Are these all ordinary twist dimmers or are there any touch / smart types involved?
3) Do you know whether any of the lights are wired 3-plate or are they all fed L & N from the switches?
4) How many cores are in the cable linking switches 1 & 3 directly and the two to the intermediate?
5) Please list which lights are switched / dimmed from which locations. You imply on the drawing that all three sets of lights (presumably ignoring the outside and security) are 2-way, but there are not enough switches and cables for that to be the case, and one too many dimmers.

You were concerned at not having a neutral at the switch without the supply. If there are two 2-ways going via two 3C+E cables, we can do a trick where one 2-way takes a PL and the other the N, and reconstruct the supply at the remote switch for the outside and security lights. There are various pros and cons but lets get a more comprehensive wants list before looking at those.

 

[gazdkw82]

Thanks lucien.

Like I said on the first post lighting is not my strong point. I dont do enough of it to be proficient on the ways in which a set up like this could be set up. FYI I am recently qualified, completing both my NVQ and AM2s, also have my 2391. Passing these qualifications means sod all if you dont actually work on something for a long time. Plus this is some else's design which only exacerbates the complexities. We all need a gentle reminder or heads up.

All the cables to switches are 3 core (T+E). All back boxes are single gang. The occupiers said they asked for the 3 feature lights to be controlled from all switches, the spots just by the first switch.

No dimmers have been purchased yet. My friend was planning to buy the dimmers today which is when it occurred to me about the neutrals.

I have confirmed the supply cables from the board (all cables are currently looped above the consumer unit) this confirms neutrals are indeed at the switch.

All lights were asked to be dimmable (excluding the outside lights which I planned to put in their own 2 gang 1 way switch)

Hope that helps.

I will do a more detailed drawing later when km on my break

 

[Lucien Nunes]

All the cables to switches are 3 core (T+E)

Even the ones between the switch positions? If so, this means that with conventional switching and dimmers, the feature lights can be 2-way + intermediate but the spots and pendants can only be 1-way, controlled from the switch position where the light cable is.

 

[gazdkw82]

Even the ones between the switch positions? If so, this means that with conventional switching and dimmers, the feature lights can be 2-way + intermediate but the spots and pendants can only be 1-way, controlled from the switch position where the light cable is.

Unfortunatly yes. I initially thought that would be enough but that was based on old style of wiring to a rose plate.

 

[Lucien Nunes]

If the intention was for feature lights on 3-way and all the rest 1 way, then the original spark pulled exactly the minimum amount of cable. The run directly from switch 1 to 3 has to be an L+N feed, and the cable via the intermediate has to be the two strappers run as conventional 2W. The dimmer for the feature lights can be at either end. If either of the other lighting groups needs control from more than one position it will have to be smart dimmers connected by WiFi, but at least there will be L+N at all switch positions.

 

[gazdkw82]

Done a quick diagram. Does this look right?

All neutrals/earths will be linked out at the switch.

Essentially the twin and earth leaving switch 1 going to switch 3 is acting as common link and a supply of neutral and earth?

The permanent live for the 3 way and intermediate comes from the supply at switch 1?

 

[Lucien Nunes]

Not quite, for two reasons

1) The multiway switching is shown using 'conversion' wiring, where PL and SL go to L1 and L2 and the commons are linked. Using this method as a 2-way allows you to take PL and SL to / from either switch because the strappers connect corresponding terminals in the two switches. But with one or more intermediates that is no longer possible; PL and SL must connect to the same set of strappers otherwise with the intermediate(s) 'crossed' the two are connected directly together and the 2-way switches cannot turn the light off.

2) Also because of the intermediate changing over L1 and L2, there is no PL at switch 3 to feed the outside lights.

Solution:
The cable that runs straight from one switch to the other is simply a loop-through of supply L, N & E. This enables the outside lights to be powered. The multiway is then wired with 'conventional' wiring with PL to Switch 1 COM, L1 and L2 via the intermedate, and feature lights SL taken from switch 3 COM.

 

[gazdkw82]

Ah ok,

Is this correct now then?

 

[Lucien Nunes]

Yes, exactly. The only choice the customer has is which end of the room (S1 or S3) gets the feature lights dimmer and which end the switch. If they want any more control you're in Quinetic territory, where you would scrap the 2W strappers and use the cable from S1-S2 as a feed.

 

[gazdkw82]

What would happen if you have more than 1 dimmer for set up?

Think they are looking to have simmers on the spots and pendant. That means switch 1 would be a 3 gang dimmer.

Intermediate would be a standard switch and switch 3 another dimmer.

The simmers they have do not require a neutral