rr said:
I never let clients tell me how to do my Electrical design. If your client insists on this type of design and you're not comfortable with it, ask for it in writing. That way, when breakers start to have nuisance trips 12 weeks down the road, you'll have paperwork to back up your design.
Also, ask them to explain
why they think this is appropriate in writing. They might be working with assumptions that don't work under all possible circumstances. For example, a lot of equipment I see these days comes with dual power supplies and your customer might have this notion that they only need to size things half as big as if all the equipment was connected to a single phase or whatever. Well, if a breaker trips, the entire load is going to be instantly dumped onto another circuit, which could trip in turn, and depending on how the loads are divvied up, the entire room could come crashing down.