Converting 2 gang 1 way and 1 gang 1 way switches to 3 gang 2 way

[brianmoooore]

I hadn't seen Avo Mk8's post when I wrote my last post. We've both written the same thing.
Yes, feed the L2s with the 'live' already present near them, then 6 wires between the two sites. These can be 2 x 3&E or 3 x T&E.
What none of them can be is a repurposed earth wire.

 

[Luka]

Like that?

Do I need to connect earth wires in the strappers to terminals in the back boxes or can I leave them loose?

 

[Luka]

I hadn't seen Avo Mk8's post when I wrote my last post. We've both written the same thing.
Yes, feed the L2s with the 'live' already present near them, then 6 wires between the two sites. These can be 2 x 3&E or 3 x T&E.
What none of them can be is a repurposed earth wire.

Like that?

Do I need to connect earth wires in the strappers to terminals in the back boxes or can I leave them loose?

 

[brianmoooore]

That appears correct. All earth wires must be connected at at least one end to the incoming earth wire, which should be tested to confirm it does actually connect to the supply earth terminal. It is preferable that they're connected at both ends.
It should also be confirmed that both incoming lives are actually part of the same circuit.

 

[Luka]

That appears correct. All earth wires must be connected at at least one end to the incoming earth wire, which should be tested to confirm it does actually connect to the supply earth terminal. It is preferable that they're connected at both ends.
It should also be confirmed that both incoming lives are actually part of the same circuit.

100% the same circuit in the CU. Cant I just use for example 3 core YY cable instead of 3+E? Both boxes are already grounded by feeding cables