Discuss New circuit to detached shed/garage in garden. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Reaction score
6
Hello I am new to this forum and need a little help from an experienced spark to help me design a circuit to wire a detached garage (two sockets and ceiling lights) from a house ring main to 18th edition standards. This will be notifiable so everything has to be pukka. Cable can be in steel trunking or armored but prefer steel trunking option. I do know the basics but as this is my first outbuilding wiring I would really appreciate some pointers. My idea is to replace a socket in the house to a switched 13 A FCU drill through wall to outside and use steel trunking buried under garden slabs to garage wall. Drill through garage wall and connect cable to an RCD (thinking that a mini CU is overkill) as the house CU doesn't have RCD protection. At this point not sure of best option to split garage supply to sockets and 3 amp protected lighting..... Thanks for your help.
 
While you can go off a FCU for this, bear in mind you're obviously limited to 13A for everything, which could be an issue for a garage. I wouldn't bat an eyelid if it was (for example) a tiny shed that might have a single socket for someone to plug a lawnmower in every so often, but a detached garage is a different kettle of fish. If someone decides to plug an electric heater into one socket while using a power tool in another, that could easily take you over the limit.

Much better IMHO would be to go back to the consumer unit, and come off a dedicated RCBO.
 
What's wrong with that suggestion Murdoch?

I think he may be getting at, if the OP is going to use a CU in the garage then that will have a RCD on it. The armour cable doesn't need it. This avoids discrimination in RCD's.
I could be wrong though.. :)
 
I think he may be getting at, if the OP is going to use a CU in the garage then that will have a RCD on it. The armour cable doesn't need it. This avoids discrimination in RCD's.
I could be wrong though.. :)
Oh OK thanks for that
 
Thank you for your input. As I suspected not a straight forward job. Yes it is a garage that will be used as a relaxation room with a fridge freezer and in the winter their may well be a heater. However my main concern would be voltage drop with the 10m run from house to garage. The good news is that there is very little demand on the ring so if there is a 13 amp fcu to garage and 3 amp to lighting and these connected to an RCD I think it would work. My confusion is the best way to achieve a tidy job without a mini CU in the garage. And what is in line with 18th edition guidelines. There won't be an issue with RCD discrimination because the house does not have one on the main CU. Thanks
 
Yes it is a garage that will be used as a relaxation room with a fridge freezer and in the winter their may well be a heater.

Are you sure 13A will be enough for the 'relaxation room'?.
A 2 KW heater & fridge freezer may be near that, or over.
May be better to wire back to CU so they have more options on what to use in the garage.
 
Yes I agree and to make future proof. I guess you are right but its more complicated to achieve and not sure the customer will be keen. It would be good if I could present him with both options and pricing so he can decide. Hence also need to know the best way to arrange the wiring in garage if taken from Ring. Thanks for your input. This job is happening on Monday weather permitting :)
 
Definitely find out what sort of heater they plan to use.
 
If you are going to tap of the existing ring then I would quote for LED lights. Give them more to play with on the socket front.
 
Thanks everyone for you input much appreciated. So was on site again today and it would be a much bigger job to hook up to CU as there would be 40 slabs to remove instead of 4. Agreed LED lighting for sure. Got as far as FCU house side from ring main to 2.5 twin&earth in trunking put down under slabs with warning tape to garage (6m total cable length) . But in the garage I would like to go connect to an RCD and from RCD split to lighting FCU and the other straight to mains sockets. Or would you advise a mini CU with RCD and 2 MCB's? Thanks for your help.
 
Thanks everyone for you input much appreciated. So was on site again today and it would be a much bigger job to hook up to CU as there would be 40 slabs to remove instead of 4. Agreed LED lighting for sure. Got as far as FCU house side from ring main to 2.5 twin&earth in trunking put down under slabs with warning tape to garage (6m total cable length) . But in the garage I would like to go connect to an RCD and from RCD split to lighting FCU and the other straight to mains sockets. Or would you advise a mini CU with RCD and 2 MCB's? Thanks for your help.
 
New posts

Reply to New circuit to detached shed/garage in garden. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock