Fuse Discrimination

[jmshep]

There have been some recent posts about connection to washing machines etc.
In one post it was suggested that a switched FCU was fitted above the worktop feeding a 13A socket below. An option suggested that a flex connection unit be used instead of the 13A socket and that this would avoid fuse discrimination. (13a fuse in FCU and 13A fuse in plugtop).

I understand that as good practice but my question is:
Is the discrimination issue in the above not the same for a fused spur feeding sockets ? It would be more than likely that a 13A fuse would be fitted in the FCU and also in anything plugged into the sockets it feeds.

 

[Taylortwocities]

Yes, you are correct. Strictly speaking the upstream and downstream protective devices should be arranged so that it is the fuse at the device that trips (thus powering off only the device) rather than an upstream one that may power several devices.

In practise this is not always possible. At least (in your example) the FCU and its attached sockets are all easily accessible.

A fuse in the plug situated behind a washing machine or built-in appliance is not accessible.

 

[seasickstevie]

I wouldn't think that the word 'likely' is relevant in your last sentence. All 13a plugs have fuses - otherwise they wouldn't be limited to 13 amps.
And the 'F' in FCU gives a clue.

 

[plugwash]

Personally I tend to think that if the plug fuse on a white goods appliance blows there is a damn good chance that the appliance will need to be pulled out and opened up anyway. The plug fuse isn't any less accessible then the components whose failure most likely caused the fuse to fail is it?

 

[jmshep]

I wouldn't think that the word 'likely' is relevant in your last sentence. All 13a plugs have fuses - otherwise they wouldn't be limited to 13 amps.
And the 'F' in FCU gives a clue.

But the FCU may have a 13A fuse and the ones plugged into the fused spur sockets may have 3A fuses and in that case there is not a diversity issue.

 

[PrenticeBoyofDerry]

The 3 amp plug would only allow 3 amps to flow to the appliance it belonged to, regardless of what the rating of the socket outlet or FCU, providing it was not lower than 3 amps(which would be unusual)

 

[JohnD]

I find the plugfuses on my kitchen appliances blow, on average, never.

So the inconvenience caused by having a 13A plug and socket behind the appliance is nil, but the convenience of being able to plug them in and out with no screwdriver or plug change required when I buy a new appliance, is huge.

 

[seasickstevie]

But the FCU may have a 13A fuse and the ones plugged into the fused spur sockets may have 3A fuses ...

Sorry... It was a bit early still

If anything, I'd substitute the 3A with 10A though for your white goods

 

[AndyPRK]

I find the plugfuses on my kitchen appliances blow, on average, never.

So the inconvenience caused by having a 13A plug and socket behind the appliance is nil, but the convenience of being able to plug them in and out with no screwdriver or plug change required when I buy a new appliance, is huge.

That sums it up well

Is this Ban under another name ?

 

[securespark]

John will be very hurt you even thought that...

 

[JohnD]

View media item 1740

 

[securespark]