Power to a shed. What are your thoughts?

[Daniel Oake]

Iv'e come across a shed that was supplied via a 13A Fused connection unit with 2.5mm squared flat twin and earth on a 15 metre run inside 20mm plastic conduit that was clipped to their wooden fence every 300mm.

Supplies 6 double sockets and one 5ft LED light fitting.

(earthing arrangement is TN-C-S and no extraneous conductive parts are present at the shed, circuit is 30mA RCD protected.
Tenants say it's over 5 years old and a DIY job)

I was curious to what your thoughts are with it not being in SWA and any other problems you may for-see with the installation.

 

[Spoon]

I'm with you on the cable type/run. Could have gone with SWA or put the cable in conduit.
Are you saying that the light is protected by the 13A fuse and wired in 2.5mm?

 

[Pete999]

Iv'e come across a shed that was supplied via a 13A Fused connection unit with 2.5mm squared flat twin and earth on a 15 metre run inside 20mm plastic conduit that was clipped to their wooden fence every 300mm.

Supplies 6 double sockets and one 5ft LED light fitting.

(earthing arrangement is TN-C-S and no extraneous conductive parts are present at the shed, circuit is 30mA RCD protected.
Tenants say it's over 5 years old and a DIY job)

I was curious to what your thoughts are with it not being in SWA and any other problems you may for-see with the installation.

What are your thoughts on the present set up Dan?

 

[Daniel Oake]

The whole circuit is spurred off the downstairs sockets 32A circuit breaker via a 13A fused connection unit, the lights are then further spurred off the sockets on a 3A switch fused connection unit within the shed but is down rated to 1.5mm squared for the lighting.

I think that within the U.K we typically see a shed fed via a 2.5mm squared twin on some string from the house that someone has thrown up in the late 90's or whatever the time, in this case protection has been met half way with the circuit being RCD protected and conduit being run for impact protection, fused connection units placed intermittently and all this.

My thoughts are that because we have left the equipotential zone of the house we now have a potential earth of just 1.5mm squared and so in the event of a earth fault I don't think this is acceptable sizing.

I would have figured 6mm 2 core SWA at the least with an earth rod at the shed or 10mm 3 core SWA bringing the earth into the shed.

Does that sound about right as iv'e been reading previous forum posts and listened to John Ward on Youtube explain exporting PME's?

 

[Spoon]

Is the plastic conduit classed as 'adequate mechanical protection'?
What is the earthing arrangement?

 

[Pete999]

The whole circuit is spurred off the downstairs sockets 32A circuit breaker via a 13A fused connection unit, the lights are then further spurred off the sockets on a 3A switch fused connection unit within the shed but is down rated to 1.5mm squared for the lighting.

I think that within the U.K we typically see a shed fed via a 2.5mm squared twin on some string from the house that someone has thrown up in the late 90's or whatever the time, in this case protection has been met half way with the circuit being RCD protected and conduit being run for impact protection, fused connection units placed intermittently and all this.

My thoughts are that because we have left the equipotential zone of the house we now have a potential earth of just 1.5mm squared and so in the event of a earth fault I don't think this is acceptable sizing.

I would have figured 6mm 2 core SWA at the least with an earth rod at the shed or 10mm 3 core SWA bringing the earth into the shed.

Does that sound about right as iv'e been reading previous forum posts and listened to John Ward on Youtube explain exporting PME's?

file:///C:/Users/Pete/Desktop/Resources/Garage-Shed%20Supplies.pdf

 

[Spoon]

file:///C:/Users/Pete/Desktop/Resources/Garage-Shed%20Supplies.pdf

Not sure what this is but it looks like a link to a file on your desktop, that doesn't work for me.

 

[Pete999]

Not sure what this is but it looks like a link to a file on your desktop, that doesn't work for me.

Yes I realise that now I have tried to open it, got nothing else to offer the OP detail wise sorry OP.

 

[Octopus]

This is probably the most common DIY set up...... Not dangerous imho.

Next

 

[Pete999]

This is probably the most common DIY set up...... Not dangerous imho.

Next

Agree with Murdoch, but not an ideal install, better would be : new circuit from House CU separate mcb, wired in SWA, with RCD protection added if not already included.
Next

 

[Devonchris]

Many new builds which have power to garages as a extra (requested by the buyer ) are done this way.

Not saying it's ideal, but somebody must be signing it off as compliant.

 

[Pete999]

Many new builds which have power to garages as a extra (requested by the buyer ) are done this way.

Not saying it's ideal, but somebody must be signing it off as compliant.

Maybe Chris what you are referring to are attached Garages, I have seen many joined garages with a fused spur unit as the supply, but have never come across a detached one as an extra, at leased not an official one, could be someone may have bunged the Sparky a few quid to do it on the QT

 

[HandySparks]

Maybe Chris what you are referring to are attached Garages, I have seen many joined garages with a fused spur unit as the supply, but have never come across a detached one as an extra, at leased not an official one, could be someone may have bunged the Sparky a few quid to do it on the QT

Pretty standard around here. Allows the builder to advertise 'power and light to garage' at minimum cost.

 

[Pete999]

Pretty standard around here. Allows the builder to advertise 'power and light to garage' at minimum cost.

Agree more money for the underground mafia on many housing sites, and don't tell that that ant the truth, I've been there, done it and got the T shirt.

 

[buzzlightyear]

most new built garages separated from the mother house via 2.5 SWA spurred from a 13amp sw/fuse ring to two way wylex board and from their .