10a switch protection with 16a breaker

[tomodo]

Hi everyone , ive been reading up on it and is it true that you can have a bank of 10a switches supplied by a 16a circuit breaker as long as each switch is only designed to be taking 10a or less? Surely if a fault was to occur then the switch would burn out before the breaker tripped? Any regulations to back this up? cheers.

 

[D Skelton]

I can't remember the exact reg, but section 433 is where you need to be looking.

 

[Lucien Nunes]

Suppose the load is a fixed one of 3A. If you are going to get any more current flowing through the switch than 3A it's going to be because of a fault and in that case it won't be 13A but probably more like 3000A. Then, it's down to the adiabatic properties i.e. how much damage the huge fault current does before the MCB opens. This is a different consideration to the thermal current rating i.e. how much it heats up over time with a certain steady load.

Manufacturers aren't stupid - they make switches and accessories that can withstand the impulse to clear the protective device let-through, so that you can use reasonable sizes of circuit.

 

[Deleted member 26818]

It is quite possible for the 10A switch to be damaged due to overcurrent conditions, either due to a fault, or because it is underrated.
Usually the contacts will weld themselves together, and the switch will require dismantling to release the contacts before it will operate again.

 

[davesparks]

Well they say to use 0.5mm to 1mm flex. Sorry i don't understand what you mean surely you need to provide fault protection aswell?

Yes you need fault protection, it's overload protection that you do not need when the load is fixed