Electrician Jobs Installing a secondary consumer unit in the garage??

[TheDoctor]

Morning all,


I am looking to install a secondary consumer unit in my garage, linking from my existing house consumer unit.


The first question is If it is ok to run 16mm2 Twin and earth SWA through my hallway and lounge concrete floor in order to get to the garage or should I be running it through the walls? I intend to run a 60A supply to the garage. I could run conduit in the concrete floor?


Secondly, would it suffice to add a 60A rated RCD to the existing house consumer unit for the SWA to run to the garage. The garage consumer unit would then just have a mains switch and MCBs for each circuit.


I intend to run a ring main for sockets all round the garage, a radial for three florescent lights and potential a radial high amp outlet for a welder.

 

[telectrix]

firstly, the SWA itself does notneed RCD protection unless the house is TT earthing. better to fit RCD in garage, then a fault in the garage will trip in the garage, not the house. Secondly, should be no problem burying SWA in concrete floor, but I'd duct it.
you could fit a 63A MCB (house end, non-RCD), then sub-board in garage with RCD and appropriate MCBs.

 

[Deleted account]

If your running twin and earth you will need rcd protection if depth of cable is less than 50mm deep in walls and floors. There are a few other criteria too you would need rcd protection for. Also you need to know the correct zones for running the cable.

However you don't need rcd protection of the supply cable if your running it in SWA.

Peter

Edit: Bugger beat me to it tel

 

[TheDoctor]

Thank you for your prompt responses.


Can I ask what sort of ducting would be ideal to run the SWA in and why I need the ducting if its SWA?


Do I need RCD protection if I am less than 50mm but in SWA?


In terms of zoning I am struggling to find info as most diagrams show wall and ceiling wiring zones. I am simply going through the hall and lounge floor to the outside.


My house is a new ish one using TN-C-S earthing


Regards,

 

[Octopus]

May be you should get a local spark involved and if you are in England or Wales this work falls under part p

 

[telectrix]

ducting protects the SWA from any possible reaction with the concrete, and also gives it that extra protection from mechanical damage to the sheath. any 2" or thereabouts plastic duct will do. zoning applies mainly to cables buried in walls. there's a perfect diagram in OSG.

 

[TheDoctor]

Thanks,

Whats everyone thoughts on running twin and earth through insulation. Does it just need up-rating for heat dissipation? or should it be run through conduit?

 

[TheDoctor]

Can I also ask that if I pay a sparky to install a ring with a few sockets and a few lights. Can I add to the ring and lights without notifying the authorities?

 

[Octopus]

Said spark needs to do the sub main and the initial circuits ....
After that it's possible for you too make changes to said circuit.

What do you plan to use in the garage?

 

[telectrix]

Said spark needs to do the sub main and the initial circuits ....
After that it's possible for you too make changes to said circuit.

What do you plan to use in the garage?

think basic sockets and lights initially, but he stated he was planning on getting a welder. the load of the welder need to be considered before designing the installation.

 

[Octopus]

^^ hence my closing sentence .....

 

[TheDoctor]

I am an engineer by profession and have a welder, lathe and mill. I need a sub main, socket outlets and lights. Potentially a higher rated fused outlet for a welder. If i were to add more sockets or lights I would hope its something I can do without need it signed off again? As long as I am not adding another circuit to the sub main?

I assume in the garage I can just run the twin and earth clipped straight to the single leaf wall or through conduit?

 

[TheDoctor]

The welder will be pulling 45 Amps, just checked and the power is 11kw

 

[Strima]

What rating is the DNO fuse?

 

[TheDoctor]

I have a 100amp supply so assume 100Amp

 

[davesparks]

I am an engineer by profession and have a welder, lathe and mill. I need a sub main, socket outlets and lights. Potentially a higher rated fused outlet for a welder. If i were to add more sockets or lights I would hope its something I can do without need it signed off again? As long as I am not adding another circuit to the sub main?

I assume in the garage I can just run the twin and earth clipped straight to the single leaf wall or through conduit?

All electrical work should be carried out in accordance with BS7671, this includes inspection, testing and certification of the work. Notification for the purpose of part P however wouldn't be required for the extension of the circuits if not in a special location.

Clipped direct cables would not be appropriate to the workshop kind of environment, I think the most suitable option would be steel conduit due to the risk of damage to the cables from weld spatter, metal chips and general moving of materials and heavy tools.

 

[David M]

The welder will be pulling 45 Amps, just checked and the power is 11kw

I assume this is an arc welder? It will most likely require hard wiring into an appropriate rated isolator. During use of the welder you may notice a voltage drop which will cause lights to annoyingly flicker. Long continued use will cost you dearly in your electricity bills. (just some friendly advice)
From experience, if you intend to use this as a "professional" workshop then be aware that the council/authorities may get involved and you will require planning permission.

 

[Loki]

Hi,

Where did you get that 100 Amp from?
If it was on the dno's main fuse housing then the fuse inside could be less.
As your not ment/allowed to pull the main fuse "but people do i know lol" you would need to call you supplier & confirm this.

Michael

 

[Loki]

Deleted double posted for some reason

 

[TheDoctor]

Hi,

Where did you get that 100 Amp from?
If it was on the dno's main fuse housing then the fuse inside could be less.
As your not ment/allowed to pull the main fuse "but people do i know lol" you would need to call you supplier & confirm this.

Michael

Why do I need to know this?