Multiple COM wires slipping from light switch

[billyb_1234]

Hi,

The wiring for my lights have multiple COM wires in most rooms, which are a pain to screw into the COM part of the switch. The switches that were fitted when I moved in work fine, but I purchased a smart switch which has slightly different sized screws / screw holes etc, and I can only seem to install it in the one room where there is just one COM wire. When I try to install it in the other rooms, the wires always slip out. I am planning to order more of the smart switches but need ideas of how I can install them in the other rooms. The switch is https://www.amazon.co.uk/Candeo-compatible-dimmable-incandescent-multiway/dp/B091HP42S8/

One suggestion I have heard is to connect all the COM wires to a screw terminal then have a wire from that to the switch. This involves finding a screw terminal that the wires won't slip out of but could be easier than putting them directly into the switch. The worry with this is I have relatively small back boxes and theres not loads of extra space in them for this.

Any advice would be appreciated.

 

[littlespark]

Looks like 25mm back box with a little extra. Should be plenty room, even with the neutral joint in there.

3 cables in one terminal is pretty standard, but smart switches can be smaller. The idea of a joint in the box, and bringing one wire to the switch is valid.

WAGO or the Ideal brand of push-in connectors are flatter and don’t take up as much space as the traditional choc block screwed terminal.

Smart switches might need a bit more space actually. Some state they need a 35mm box.
You can also get white plastic extensions that allow more space but the switch sits away from the wall a bit.

The top and bottom screw lugs on those boxes are a nuisance as well. Not needed. They can be bent back out the way.

 

[Lucien Nunes]

the wires always slip out.

A general requirement for all electrical work is to make good, secure, reliable connections using appropriate materials. There should never be the slightest doubt about the fit of the conductors in the terminals or their suitability for the purpose.

Wago 221's are nice, compact, versatile lever connectors, that would be ideal to pigtail the line conductors to your switch commons. The Wago 2273 is a push-wire type that is probably the smallest / neatest on the market.
e.g. COMPACT splicing connector (2273-203) | WAGO GB - https://www.wago.com/gb/installation-terminal-blocks-and-connectors/compact-splicing-connector/p/2273-203

I can imagine that the smart switches are a bit deeper and need more room in the boxes but a general tidy-up can liberate lots of space. Trimming the grey cable sheaths back to just inside the grommet, carefully routing the earths out of the way around the edge, ensuring wires dont cross over, making them loop down and up smoothly between the entry and the terminal. It's amazing how much easier it is to work and fit things in when the cables are properly prepared and dressed; a point that many 'electricians' don't seem to care about so long as they can scrunch it all in somehow.

 

[BenCos18]

Add a wago 221 to the com wires and run a wire from that to the switch