ChrisPDuck
DIY
Short Version
The longer version
I have a detached garage ~ 2m from my house which has an existing SWA feed (installed before I purchased the house).
I brew my own beer and the kit can draw quite a chunk, 3 x 16A draws at max power (this is software adjustable so at the moment I have this set to 3 x 13A and one of these I plug into the house to split the load across different breakers (these circuits are completely separate electrically so this is fine)
It’s been on my to do list for a while to get a more suitable feed installed to the garage so I can use the full power of the gear and avoid having to trail one of the plugs to the house. Bad planning on my part means I’m having a tile patio installed late this week so sorting this after that point will be much harder / costly / possibly always be visible.
No chance of me getting a sparky in time so I want to do what I can, the easiest is obviously for me to just install ducting/conduit between the buildings so the sparky can do what they want, how they want at a latter date.
However I haven’t seen SWA in ducting before and I suspect there may be a reason for this? (I’m a telecoms engineer by trade, we put everything in ducting, it makes any upgrade/maintenance/repair work so much easier in the future). If this isn’t permissible my preference would be to get the SWA buried while the foundations for the patio are being sorted.
This is where things get interesting.
The garage is fed from a 32A breaker (with 30ma RCD) in the house and then has a 63A main switch in the secondary consumer unit in the garage, this also houses a 32A breaker for the mains sockets and 6A breaker for the lighting. What seems utterly inappropriate / unsafe is upon investigation this is fed from a 1.5mm SWA between the buildings?!? A 1.5mm feed protected with a 32A breaker? Surely that isn’t right (this looks like it was done when the property was built by the way, it doesn’t look retro fitted).
So I guess I have 2 choices, the easiest would be to leave that as is and put a second SWA feed to the garage to feed a second consumer unit with 3x16A sockets (something like this Hook Up Unit 3 x 16A Socket & RCBO - https://www.toolstation.com/hook-up-unit/p34313 ) I have the space in the main consumer unit for the breaker to do this. As there would be no wiring outside the consumer unit there would be no risk of someone in the future assuming the power was off to a cable having turned off the wrong breaker, so it passes the common sense test to me but I’m unsure what the regs allow? I assume a 10mm SWA cable would be ok here (max draw 10kW, 10m run)
The alternative would be to replace the lot, so rip out everything there and put a new SWA feed in to a new consumer unit which supplies 3x16A sockets, 8x normal 13A double socket and the lighting. But I assume this will cost much, much more as I believe I will need 16mm SWA, a larger consumer unit and separate 16A sockets etc.
I’d appreciate your thoughts.
- Is it permissible to have 2 feeds to 2 separate consumer units in a detached garage?
- Is it permissible to run SWA underground through a duct/conduit or must it be direct in ground?
- What diameter SWA would I require for a 10m run, buried and clipped to wall, feeding 3 x 16a sockets (max draw 10kW) – I believe 10mm?
- What diameter SWA would I require for a 10m run, buried and clipped to wall, feeding 3 x 16a sockets and 8 normal 13a double sockets?
The longer version
I have a detached garage ~ 2m from my house which has an existing SWA feed (installed before I purchased the house).
I brew my own beer and the kit can draw quite a chunk, 3 x 16A draws at max power (this is software adjustable so at the moment I have this set to 3 x 13A and one of these I plug into the house to split the load across different breakers (these circuits are completely separate electrically so this is fine)
It’s been on my to do list for a while to get a more suitable feed installed to the garage so I can use the full power of the gear and avoid having to trail one of the plugs to the house. Bad planning on my part means I’m having a tile patio installed late this week so sorting this after that point will be much harder / costly / possibly always be visible.
No chance of me getting a sparky in time so I want to do what I can, the easiest is obviously for me to just install ducting/conduit between the buildings so the sparky can do what they want, how they want at a latter date.
However I haven’t seen SWA in ducting before and I suspect there may be a reason for this? (I’m a telecoms engineer by trade, we put everything in ducting, it makes any upgrade/maintenance/repair work so much easier in the future). If this isn’t permissible my preference would be to get the SWA buried while the foundations for the patio are being sorted.
This is where things get interesting.
The garage is fed from a 32A breaker (with 30ma RCD) in the house and then has a 63A main switch in the secondary consumer unit in the garage, this also houses a 32A breaker for the mains sockets and 6A breaker for the lighting. What seems utterly inappropriate / unsafe is upon investigation this is fed from a 1.5mm SWA between the buildings?!? A 1.5mm feed protected with a 32A breaker? Surely that isn’t right (this looks like it was done when the property was built by the way, it doesn’t look retro fitted).
So I guess I have 2 choices, the easiest would be to leave that as is and put a second SWA feed to the garage to feed a second consumer unit with 3x16A sockets (something like this Hook Up Unit 3 x 16A Socket & RCBO - https://www.toolstation.com/hook-up-unit/p34313 ) I have the space in the main consumer unit for the breaker to do this. As there would be no wiring outside the consumer unit there would be no risk of someone in the future assuming the power was off to a cable having turned off the wrong breaker, so it passes the common sense test to me but I’m unsure what the regs allow? I assume a 10mm SWA cable would be ok here (max draw 10kW, 10m run)
The alternative would be to replace the lot, so rip out everything there and put a new SWA feed in to a new consumer unit which supplies 3x16A sockets, 8x normal 13A double socket and the lighting. But I assume this will cost much, much more as I believe I will need 16mm SWA, a larger consumer unit and separate 16A sockets etc.
I’d appreciate your thoughts.
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