Cheers Eddy. Once the case is finished it will be dust tight (I think your case is the same design). I figure anyone inside the case should have a pretty damn good idea of what they are doing or they shouldn't be in there! The cover over the power supply is stop stupid accidents, it wouldn't stop a concerted effort to electrocute yourself.

I don't remember seeing any spec's for space around the rectifier although I'm guessing there will have been some. There's a good bit of space around it though and the aluminium it's bolted too will act as a great heat sink. I'll keep an eye on it but I don't envisage a problem. I don't like the way the bleed resistors are connected at the moment, it feels like a bodge although it works fine. I was asking about the power supply over on another forum and someone pointed me in the direction of active rectifiers, apparently they dissipate almost no power - I bet they cost a fortune though.

Something else I meant to ask, how are you connecting the various bits inside your cabinet to the various bits on the outside e.g. steppers, e-stop / limits etc. I'd like to be able to just unplug everything and take the case away but I'm concerned plugs and sockets will introduce noise.