What size Fuses do I require?

[Gavin Millar]

Hi,

I have a three phase switch fuse supplying a 16A socket. In the specification provided it states the following:

Design Current - 16A
Main Protective Device 20A

The circuit is fed from a C20 MCCB at the distribution board.

What size of fuses should I be putting in the switch fuse?

16A or 20A?

Thank you.

 

[westward10]

I agree for a single point socket 16A. But it is suggested 20A can be used although I admit these things in GN1 are not necessarily Regulations.

 

[7029 dave]

Hi,

I have a three phase switch fuse supplying a 16A socket. In the specification provided it states the following:

Design Current - 16A
Main Protective Device 20A

The circuit is fed from a C20 MCCB at the distribution board.

What size of fuses should I be putting in the switch fuse?

16A or 20A?

Thank you.

Op no mention of cable size, ccc is a main factor.

 

[Wilko]

...20A is due to the fact a radial of more than one 16A socket can be employed ... however if the circuit supplies one 16A socket I see no reason to use anything above a 16A protective device.

Agree.
Apologies for my dumb question but why are there additional fuses being spec'd here? Local isolation yes, but it's already got a C20 at the board so shouldn't the question be "do I keep the C20 or go to C16?"