Quote Originally Posted by dazp1976 View Post
When it comes to a DC power supply for steppers etc, say example a switched. We'll go a little overboard here.
Lets say you have a 60Vdc, 16.6A, 1000W big unit. This is it's max OUTPUT.
It doesn't mean that it uses 16.6A from the mains and needs a breaker.
You're INPUTTING 240Vac to it, so 1000W on 240Vac is actually 4.16Amps.

If you're building a control box with these types in you'd prob only want a 6A or 10A for the above size supply.

You don't see a 1000W heater or toaster or kettle needing a MCB.

Something like that anyway.
And you totally missed the point Muzzer was raising.

Plus it's not like it's not unknown for heaters, toasters, and kettles to go up in flames.
Just because the accepted default fuse size is 13A, doesn't mean it's the ideal size to use.