SWA (Surprisingly Weird Arrangement)

[HandyMann]

So I’m an inexperienced novice and I accept I know two ninths of four fifths of FA but when was this arrangement ever ok?
Installing like for like replacement garden lights, currently connected to a run of 4 core 1.5mm SWA emerging from ducting under patio. Somewhere further back it’s joined to lighting circuit and then back to 6A RCBO.
Brown and blue cores utilised for L and N of lights.
Grey and Black cores are also put to use, as L and N for an outdoor 13A socket at the end of the garden. The armour is providing the cpc and zs measurements at lights show it’s doing a fine job.
The switch for the garden lights also disconnects the line to the outside socket.
Am I missing something here? I’ve told clients that the socket has to go.

 

[Toneyz]

I’ve agreed to leave it connected but will install a fcu prior to the socket labelled at 5A max. I’ve no reason to believe this was a diy install.

I can't see the point. Is the socket and lights around garden switched separately? An IP outside socket from a local ring final circuit or radial would be a better solution.

 

[Toneyz]

I’ve agreed to leave it connected but will install a fcu prior to the socket labelled at 5A max. I’ve no reason to believe this was a diy install.

I can't see the point. Is the socket and lights around garden switched separately? An IP outside socket from a local ring final circuit or radial would be a better solution.

 

[HandyMann]

I can't see the point. Is the socket and lights around garden switched separately? An IP outside socket from a local ring final circuit or radial would be a better solution.

Yes I agree.
It’s the customer’s choice in respect of not wanting the expense of another swa to the end of the garden when there is one there serving his socket already.
Thinking it through, accepting that I don’t know how it originates, the only issue as it stands is the potential nuisance tripping of the 6A OCPD, hence a 5A FCU prior to the socket.

 

[davesparks]

the only issue as it stands is the potential nuisance tripping of the 6A OCPD, hence a 5A FCU prior to the socket.

What is the 5A fuse supposed to achieve, it will not discriminate with a 6A RCBO!

 

[123]

I don't see how a 5A fuse will make a jot of difference between a 6A RCBO

 

[HandyMann]

What is the 5A fuse supposed to achieve, it will not discriminate with a 6A RCBO!

OK that was an option made on some assumptions on my part.
I made that choice based on the only operating times that are available for BS1362 fuses, ie 3A and 13A.
These suggest that the 3A would easily provide discrimination against the 6A rcbo and I thought a 5A would do the same however I bow to your greater experience on the matter.

 

[Richard Burns]

A 5A fuse will probably blow before a 6A MCB in a slight overload situation e.g. up to about 18A, at higher currents either one could go first.

 

[HandyMann]

A 5A fuse will probably blow before a 6A MCB in a slight overload situation e.g. up to about 18A, at higher currents either one could go first.

Thanks Richard

 

[Chivers]

How far is this run exactly? The 1.5mm must be derated by a chunk large or small? Can't understand why 2.5mm or 4mm wasn't used. This should have been on an RCD or RCBO from the off even under the 16th Edition if an outdoor socket was indeed installed back then.

 

[Toneyz]

Under the 16th wasn't it that RCD protection had to be for socket outlets that were for general use by ordinary persons & mobile equipment 32A and under. Reading the post it seems that this socket was not intended to be used as a general socket outlet for equipment outside(or mobile)just a way of connection of outside permanent lighting.

 

[HandyMann]

Under the 16th wasn't it that RCD protection had to be for socket outlets that were for general use by ordinary persons & mobile equipment 32A and under. Reading the post it seems that this socket was not intended to be used as a general socket outlet for equipment outside(or mobile)just a way of connection of outside permanent lighting.

The socket is no longer working but customer wants it replacing. It was for general use rather than dedicated to supplementary lighting.
I suspected it should’ve been RCD protected when installed but was unsure of dates.