Denis,

Welcome to the Forum.

There is no need to have a special electricity supply. You should be able to connect the SWCG off the timer. Many have installed SWCGs themselves, without any problems.

Regarding the pool stairs, you may need to connect a ground wire back to ground connection on your "ground protected" supply. It's called a GFCI (ground fault current interrupter) in the US.

If the electrical codes allow you to instal it then go ahead. I did mine myself.

Pat