Help making sense of new touch dimmer 2 way switch plz.

[VickyBH]

Hi,
I bought some BG touch dimmers to replace my existing 2-way switches, but the terminals on the dimmers are labeled L, S-Link, and Load, instead of the usual Com, L1, and L2.

I have a 3-core cable running between the two switch locations, with the neutral wires connected via WAGO connectors at each location. The wiring diagram for the new dimmers suggests that all three wires should be directly connected between L, S-Link, and Load. However, if I do this, I’ll lose the neutral connection, which doesn’t seem right.

My current setup is that the feed goes to the switches first, and the BG wiring diagram seems to be the traditional 3-plate method, where both the live and switched live wires from the light connect to the dimmer. In my case, only the switched live goes to the switch. Could you help me understand how I should connect the terminals in my setup?

 

[ericmark]

Clue is in the advert and instructions both the switches need to be replaced, one with the master the other with a slave called here secondary, the S wire tell the master what to do.

The school boy method used to wire your lights is unusual

even using that method, normally the wires are run

but normally wired

as there is no need for a connector in the switch, so with your method you will need to run more wires to use that switch, sorry.

 

[Murdochcat]

You can only have 1 dimmer on lights with 2 way switching (mostly)

 

[ericmark]

You can only have 1 dimmer on lights with 2 way switching

Clearly that is not the case, you can have master and slave with many makes, there was a make with just two wires between master and slave, but the line was discontinued, it is the same with smart on/off switching, energenie also do the master/slave switching, however never seen the slave for sale without it being sold as a pair with the master.

But problem here is way it has been wired, that method is unusual.

 

[RandomGrinch]

so with your method you will need to run more wires to use that switch, sorry.

I think they may have a chance, if they can find a neutral for the light from somewhere else on the same lighting circuit (and safely isolate the incoming neutral/s)?

 

[ericmark]

I think they may have a chance, if they can find a neutral for the light from somewhere else on the same lighting circuit (and safely isolate the incoming neutral/s)?

Yes good plan, but one needs to be careful it does not result in a borrowed neutral.

The problem when taking a neutral from else where, is one if either neutral or lines go through a hole in ferrous metal on their own, so steel back boxes are out, and that if a circuit is isolated, that the line from another circuit does not make it live, once the neutral (which is considered as live) is thought to be isolated.

Since the question has been asked, one has to assume the question has not come from an electrician, so likely they will be unaware of the problems taking only the line or neutral through a hole, it only requires a saw cut to make it a slot rather than a hole, I have done that many times, but not some thing a DIY guy would think about.

 

[333rocky333]

If unable to resolve the simplest way is to use one standard type dimmer and one standard 2 way switch, may not give the look you desired and will obviously only adjust at one point but without going down a more complex route of master and slaves or WiFi, your existing wiring is likely to need reconfiguring.

I do believe there are some dimmers that just need L and N to one point and 2 wires between

 

[EFLImpudence]

Perhaps it is possible.

Does this mean that the light grey wire is optional - not necessary?

Even the text is not clear (to me):

 

[RandomGrinch]

Perhaps it is possible.

Does this mean that the light grey wire is optional - not necessary?

Definitely worth a try?

 

[ericmark]

I would have thought the slave switch needs power to work, so without the L connected, it would only have power when switched on.

 

[EFLImpudence]

But in the Varilight diagram, it is the slave dimmer that has the line connected.

What do you think it means when it says "live wiring to slave unit is optional"?

 

[RandomGrinch]

I would have thought the slave switch needs power to work, so without the L connected, it would only have power when switched on.

I may be completely wrong, but I seem to remember reading somewhere, that there could be some (ELV?) power available through the S-link.
If there is, you could imagine the slave unit sending a control signal back to the master, to put an output on the dimmer terminal?
I'll have a look for some teardowns...

 

[EFLImpudence]

It even says the same with multiple switches and the 'L' as opposed to 'Live' connected to the master.

 

[VickyBH]

Definitely worth a try?

View attachment 358991

BG's technical department was useless. They don't even know about how their product works, just kept repeating the instruction wiring is the only way. In the end I made a little test circuit and can confirm this wiring digram works!!! The switched works without a live between mater and slave. Than you! @RandomGrinch & @EFLImpudence! and all others the chipped in.

by the way, the touch dimmer is for my elderly mother whose hand can't operate the traditional dimmer easily. She'll be well pleased now.

 

[EFLImpudence]