shower with a combi - separate feeds? tee-d off?

[londonboy123]

When installing a shower with a combi is it just a case of tee-ing off ? Unlike the conentional open vented system that has a surrey flange and separate feed from the cwsc ?
I know it is best to have a thermostatic mixer shower with a combi but what's the best way to install it?!! Curious ...

 

[seco services]

as you say just tee off your bath hot/cold.

 

[londonboy123]

just wondered - isn't it dangerous though if for eg/ someone in the kitchen uses the hot water tap? the precautions are used in an open vented syste to prevent this, what precuations are there for a combi system....?