Wiring a ring main in garage Ask questions and find answers to many subjects relating to electrics and electrical work

[ex-pc]

I have run a 30amp cable from an RCB switch in the house CU to my attached garage where I intend to connect it to a CU in the garage. I want to create a ring main within the garage. Can the ring main consist of 1.5mm cable or does it need to be 2.5mm.

[BLAKEY1963]

[quote="ex-pc"]I have run a 30amp cable from an RCB switch in the house CU to my attached garage where I intend to connect it to a CU in the garage. I want to create a ring main within the garage. Can the ring main consist of 1.5mm cable or does it need to be 2.5mm.[/quote]

ex-pc
you state a 3o amp cable , but don t tell us wat size.
yours doubts about 1.5 / 2.5 mm2 4 a ring main
suggest you need to get the advice of your local part p
electrician to advise u , and check any possible part p
implications

BLAKEY1963

[ex-pc]

It looks like a cooker cable size which the previous occupier had installed to feed a glass furnace in the garage for his wife's stained glass making hobby. I merely want to set up a ring main supply for 13amp sockets to power ordinary DIY tools etc.

[kbrownie]

[quote="ex-pc"]I have run a 30amp cable from an RCB switch in the house CU to my attached garage where I intend to connect it to a CU in the garage. I want to create a ring main within the garage. Can the ring main consist of 1.5mm cable or does it need to be 2.5mm.[/quote]

ex-pc
30A cable? how do you know that, need CSA of cable, location and enviroment of garage (distance from house, connected or seperate from house)
Then may be able to help further, with advise?
Ring Final unlikely in 1.5mm unless mims cable.
Please note part p required look on projects pages for part of building regulations, alternative use registered domestic installers scheme electrician.
KB

[moggy1968]

there's no such thing as a 30 amp cable, there's no such thing as an RCB. A ring main is a standard circuit which uses a standard cable size. This work is notifiable under part P and needs to be done by a competent person, which given the above I suspect doesn't mean you so you need an electrician!

[kbrownie]

[quote="ex-pc"]It looks like a cooker cable size which the previous occupier had installed to feed a glass furnace in the garage for his wife's stained glass making hobby. I merely want to set up a ring main supply for 13amp sockets to power ordinary DIY tools etc.[/quote]

Cookers/ovens could be run on different selection of cable sizes depending on the output of the oven, so description is of little help.
Have a look on grey/white pvc outer sheath it may have cable size on there. the breaker size that is protecting this circuit may also help providing it was installed correctly originally.
KB

[ex-pc]

[quote="moggy1968"]there's no such thing as a 30 amp cable, there's no such thing as an RCB. A ring main is a standard circuit which uses a standard cable size. This work is notifiable under part P and needs to be done by a competent person, which given the above I suspect doesn't mean you so you need an electrician![/quote]

To state my work again, I have created ring main circuits before. I repeat the garage is attached to the house. RCB or RCD it's the same thing really, a circuit breaker CU. I don't need an electrician to wire up a simple ring main in my garage. This is H&S gone mad. All I asked was if I could use 1.5mm cable instead of 2.5mm cable for a simple ring main in my garage?

[kbrownie]

[quote="ex-pc"]

To state my work again, I have created ring main circuits before. I repeat the garage is attached to the house. RCB or RCD it's the same thing really, a circuit breaker CU. I don't need an electrician to wire up a simple ring main in my garage. This is H&S gone mad. All I asked was if I could use 1.5mm cable instead of 2.5mm cable for a simple ring main in my garage?[/quote]
RCB is not a term often used regarding your residual device, Usually RCCB or RCD but hi-ho.
Your problem is the work you are considering doing, could well be effected by part p of the building regulations, although it is not a must do job by a registered electrician it must be notified.
That is a legal requirement. You may consider it madness but that's the way it is. These requirements came to be in 2006.
If ring final circuits are so simple, i'd assume you'd know the answer to your question.
The guys on here are offering you free and safe advise and also trying to explaining the legal requirements, do you want us to tell you to do something illegal, that could make your house insurance invalid and you end up in court? Hopefully you can appreciate that we do consider your safety and we don't have you doing something that will have you breaking laws.
1.5mm likely not to be big enough unless in mims, (mineral-insulated).
Your CSA of cable will then depend on the area being covered by circuit and breaker size.
KB

[moggy1968]

To state my work again, I have created ring main circuits before. I repeat the garage is attached to the house. RCB or RCD it's the same thing really, a circuit breaker CU. I don't need an electrician to wire up a simple ring main in my garage. This is H&S gone mad. All I asked was if I could use 1.5mm cable instead of 2.5mm cable for a simple ring main in my garage?[/quote]

no, they aren't the same thing, and it isn't the same as a circuit breaker (MCB) either, they are completely different and work in completely different ways. Yes you do need a electrician because you clearly don't know what you are doing! the fact you manage to bang a few cables in and make it work does not mean your circuit is either safe or legal, and thats why we have part P, it's not health and safety gone mad, it's to stop people who don't know what they are doing making dangerous installations (like ring sircuits from 1.5mm twin and earth). Every day I see installations that are so horrifying that I become more and more convinced that part P is a good thing, it's only flaw being it doesn't go far enough!

if you do know what you are doing, you can do the work yourself, providing you notify building control yourself BEFORE work commences so they can come out and inspect the work and ensure it conforms to regs and is safe. they will also check it has been properly tested (I presume you can do that, as you have done this type of work before) and certified.

as an ex PC, would you suggest I take the law into my own hands, or do you think I should leave it to the police, or is it that the legal system has gone mad that I am not allowed to sort out my legal problems in my own happy way!!!