Wiring wrong?

[diy_fun_uk]

Background. I have a lounge/diner. There are two ceiling lights, one in the lounge area, the other in the dining area. There is a double dimmer switch serving both lights, located as you enter the lounge. In the diner area there is a single on/off switch serving the dining area light. So the lounge light can only be operated from the dimmer, the dining light from the dimmer or the separate on/off switch.

I've lived in the property for circa 10 years and the lights have operated as expected, no issues. I recently installed LEDs and the buzz was ridiculous. Quick Google told me this was likely caused by older style dimmer. So I replaced it with a basic 2 gang 2 way dimmer that can handle high or low voltage. Buzzing noise greatly reduced, however the lights now take 1-2 secs to come on. Another quick Google tells me this is likely nothing to worry about, 'LEDs can do that due to the technology' however advice also states there might be a wiring issue.

I'm not sure if the dimmer is wired correctly. I simply copied the wiring layout from the old dimmer. As I say it's worked without issue all the years I've lived here and I suspect the light delay is simply due to using LED bulbs? However my bigger concern is if the wiring method is correct or dangerous?

 

[ericmark]

Unlikely a danger, however the standard wiring diagram for a two way switch was this, the wire between the two com terminals carries 230 volt, but when electronic switches are used, often the com is replaced with slave, and the slave terminal does not carry 230 volt, and you need a master and slave switch, in case of dimmer either can dim the lights.

Not all work that way, so you need to read the info that came with the switch, once you start using electronic switches be it on/off or dimming then the wiring can change, and unless you state using a set make and model of switch then hard to work it out.

This sign on a bulb means not suitable for use with dimming switch and without cross it is suitable, however there are many ways to dim a bulb, from simple resistor, to a variable transformer, with most common being wave chopping leading or lagging, and often the bulb may say suitable for dimming but not what method should be used.

Even with simple on/off switching I have had problems, lights staying on dim, flashing, and pulsating. Not dangerous but not what we want.

Some dimmer switches do have line and neutral, but most have simply line in and line out, no neutral, the line out may well be blue or black in colour, but that does not mean it is neutral, it just means the over sleeve has fell off at some time (or was never fitted).

I would say pictures are the best idea, as said unlikely any danger, but may do things which are not expected, in many countries the switch back box is used as a junction box, and you do have a neutral, but in the UK traditionally the ceiling rose is used as a junction box, this makes it easier to fit emergency lights and ceiling fans, and reduces the volt drop as cables not feed up and down each wall, but some non British electronic light switches need a neutral so will not work with UK system.

 

[diy_fun_uk]

Confession time! There wasn't just one wire connecting the second module, I was remembering incorrectly! Original post now edited. Apologies for misinformation. Still interested to know if the wiring is correct though. LEDs are dimmable.

Dimmer switch: https://www.screwfix.com/p/lap-2-gang-2-way-led-dimmer-switch-white/366cc

Pics that hopefully show the wiring clearly enough including the instructions that came with the switch: