DIY Doctor UK DIY Forums

Hello,
Which wires go to which terminals? See photo of wires and photo of switch unit.

Here are the wires emerging from my bathroom ceiling:

One large grey sheathed cable splits into 3: red, yellow and black.
One small grey sheathed cable contains only one cable in black.

The previous non-dimmable switch I removed used the following setup: The red from the triple cable and the black from the single cable both went to COM. The black from the triple cable went to L2. The yellow went to earth.

What are the equivalents of COM and L2 on the new switch and should I use the same configuration?

Here are the terminals on the new dimmable pull switch.

One side marked IN has N and L terminals.
The other side marked LOAD has an N terminal then one with a symbol which is a wavy line crossed by an arrow.

Here are the instructions:

"The LOAD cable is connected to the lamp, and should be attached to the dimpull terminal marked ‘LOAD-L’. The earth terminal on the dimpull can be used to terminate the earth conductor if required. EARTH CABLES must NOT be connected to any other terminals on the product. The SUPPLY cable should be fitted to the terminal marked ‘L - IN’. The DIMPULLSW-C has two neutral terminals (N-IN and N-LOAD) these are not required for operation and are there for convenience if a neutral termination required."

The instructions leave me with the following Q's.
Can I tell which is the LOAD cable from the previous switch's configuration that I detailed above? And which terminal does it go to? As you can see from the photo, there is no terminal labelled LOAD-L as mentioned in the instructions but presumably they mean the wavy line symbol?

And presumably the previous switch setup will also reveal which is the supply cable that should go to the L terminal on the IN side?

Should I attach the yellow cable to earth? How do I know if it is required or not?

When is a neutral termination required?

I didn't want to use my best guess in case something goes horribly wrong so any help to get definitive answers would be greatly appreciated.

Your wiring and old switch was for 2 way switching. (2 switches for the same light)

Your new pullcord switch is only suitable for 1 way switching, which is why you can not figure out how to connect it.

Since the single odd cable connects to same terminal as the red I would guess that is line in, so black is line out, there is a terminal to connect earth to, the clamp terminal to right in picture.

It says you don't need the neutral so you leave those terminals empty.

The dimmer switch needs some power to work, and an LED bulb will allow a small amount of current to flow through it to work the modern switch.

I know my remote switch works OK with a 10W LED bulb, the down side is any power cut and it auto switches off.

Thanks for the information. Are you saying that it's impossible to connect the existing wiring to my new switch?

There is only 1 switch for the single light in my bathroom.

I am saying your wiring indicates you have another switch somewhere, even if you don't use it.

(There was a similar post a while ago, the person forgot there WAS another switch in the middle of the hall)

Unless you know where the other switch is (or was) its not possible to tell you which wire to connect to what. (Unless you had a multi meter and could find out what does what then you could isolate the "non required" wire.)

Also can I ask what type of lamp it is you wish to dim? only the manufacturers instructions say it is NOT compatible with LED lamps, so if you have a LED lamp, it would be another reason you can't use your new switch.

Reading the product information, it does seem a lot of effort to dim a lamp, with the correct sequence of pulling on the string. Have you considered something like a Philips hue lamp and an amazon echo? then you could be sitting in the bath and you could tell the echo to dim the light for you. (No I am not joking, we have several of them now)

No I am saying from what you say it will work OK.

If I have read correctly you have 4 wires.
1) Earth with will just go under the clamp.
2) The red of twin and earth and the single cable which were both connected together.
3) The black wire of the twin and earth.

Mr White seems to think the two wires were not connected together, so who has got it right.

Thanks ericmark. I was replying to Mr White with my last post. Your post must have been inserted after I posted but before a moderator approved mine. Either I am not seeing the option to reply directly to someone or the option doesn't exist.

Anyway, you summarised it well. There is indeed...

1) Earth of the 'twin and earth cable'.
2) The red of the 'twin and earth cable' and the single cable (black) which were both connected together.
3) The other black wire of the 'twin and earth cable'.

And based on your advice I will wire it according to the previous switch setup ie...
1) The clamp on the back box - Earth
2) Line IN (labelled L on the dimmable switch) - The red of the 'twin and earth cable' and the single cable (black) which were both connected together in the previous switch.
3) Line out (labelled with the crossed wavy line symbol on the dimmable switch) - The other black wire of the 'twin and earth cable'.

Mr White - I can not find another switch either in the bathroom or hallway. The only other switch in the bathroom is the isolator for the shower unit. My lamp is not LEDs. And thanks for the advice about a Philips hue lamp amazon echo combination but I wouldn't consider it much effort to pull once for off or holding for dimming. I was mainly wanting the new switch because it is meant to be very quiet.

I'll post an update after I've tried to install it.