Re: I'm floored
400kg, or 4kN approximately is a lot, depending on how it's sited. A residential floor needs to be able to support 1.5kN/m^2 (BS6399). Say it's all mounted in a single 19-inch, about 0.6m x 0.6m means it's generating a load of 11kN/m^2, which is substantially over that limit.
I don't worry about entering a room with 4 people in there, but equally I don't stand in the same area as all 4 of them. As long as the room is over 2.7m^2, then you'll be fine. And fitting 5 people in a room that small isn't that common.
Not to say it wouldn't be a problem, but certainly don't bank on it.