Electrical regs question - key operated FCU

[Mike Harrison]

I'm involved in specifying the supply for an application that needs a fused connection unit with a key-operated switch. This will be supplying a device embedded in a wall, with cabling channelled from the FCU to the device. Current draw would be

[David Hansen]

On Tue, 29 May 2007 16:32:05 GMT someone who may be Mike Harrison wrote this:-

connection unit with a

be connecting to a

connected directly to the

wrong fuse gets fitted).

The contractor is not particularly au-fait with electrical design then. It is no different to fitting a spur in a kitchen which has a

20A switch at high level and a socket outlet at low level. The fuse limits the current flowing through the switch to below that which the switch is rated at. What it means is that overload and short circuit protection are undertaken by different protective devices.

Neither is it different to fitting a switched socket outlet. Does your contractor think that the switches of these are rated at

30/32A?

Why not connect the ring main to the fuse unit (which might be an interesting task). Then the switch is on a fused spur and your contractor should be happy.

[Andy Burns]

be connecting to a

Isn't that like saying e.g. on a cooker radial in 10mm^2 cable, you can't continue the 10mm^2 from the oven connection unit to an FCU for the hob, beacuse the FCU is switched at 13A while the circuit might be fused at 40A?

[Lurch]

On Tue, 29 May 2007 16:32:05 GMT, Mike Harrison mused:

connection unit with a

from the FCU to the

be connecting to a

connected directly to the

wrong fuse gets fitted).

causing offence ( e.g.

for the key

Contactum 3467 or 3469. Can't remember exactly what they are but they are switched fused spurs with key operated switches.

[Owain]

connection unit with a

from the FCU to the

be connecting to a

13A sockets and FCUs connect to a ringmain and theyr'e only rated at 13A. Unfused spurs connect direct to a ringmain and they're assumed to be a max of 20A (a double 13A socket).

connected directly to the

wrong fuse gets fitted).

causing offence ( e.g.

for the key

One aspect is that if it needs a keyswitch then there's an argument that the fuse carrier shouldn't be within reach of pupils either. So you could use a FCU at high level with a keyswitch lower down, which might keep everyone happy.

Owain

[Andrew Gabriel]

The gridswitch fuse carrier is retained by a screw, so you need a screwdriver to take the fuse out.

[Bob Eager]

When I was at school, I always carried a small toolkit...

[Lurch]

On 29 May 2007 22:09:09 GMT, "Bob Eager" mused:

I think the term for that nowadays is 'tooled up' or 'loitering with intent', or something. I had most of my tools confiscated at one point or another.