wiring up a garage

[PedroUK]

Dear forum readers and Electricians Experts,

I am planning to wire up my garage (garage room + office room) myself but ultimately it will be certified by a qualified Electrican and with a marvellous certificate, oh joy another one.

I am planning to do the following in order as far I can:
1. Run a 10mm² for about 15m from my consum unit to the edge of my internal house
2. use an SWA armoured cable in a conduit which will be burried under 500mm (including tape at around 200mm depth indicating that electric cables are run underneath)
3. run adjacent to this cable (1 foot away) another conduit including CAT5e solid cable + perhaps cable for alarm system monitored 24H by ADT.
4. Use a consum unit (2xMCB for lighthing + 2xMCB for 2 ring main including in each room 3 to 4 socket-outlets [office room+garage] + 1MCB for interior electric heating [1kW] + 1 MCB for exterior electric heating [1kW])
5. 2 independant lighting circuit with 2.5mm2 cable
6. 2 independant wiring circuits [garage + room] with 2.5mm2
7. All socket-outlets in garage will be with built-in RCDs and be of type metal clad
8. 2 FCU SPUR to connect to the electric heathers
9. 1 FCU Spur to connect to an external socket outlet water proof (IP55+)
10. 2x 1way switches for the lighting
11. All circuit will be in conduit in the garage room.
12. All circuit will be wired standard in the office (4662 boxes with plaster around)
13. The total surface of the garage is 29m2 (build reg exemption) so in term of lenght of cable, it could be up to maximum for a loop to wire both room together for socket-outlet around 25-30m.

Therefore knowing all the above I have a few questions:
1. Is 10mm² sufficient? Bearing in mind that one top of the heating I may run washing machine
2. Would anyone know the type of cable to use for ADT
3. under the wiring regs, would CAT5e requires any additional precaution such as armoured? even if I use conduit?
4. How about the earthing? Does it need to be taken down on a stick next to my garage?
5. Is the number of MCB too much? Do I really need to have 2 lighing circuit for both rooms?
6. Again can I have one large wiring ring to cover both rooms of that same building?
7. for 5. and 6. if one is sufficient for circuit required what would be the rating to take for MCB and short-cirucit capabilities? (6kA, 10kA 10A-20A...)

Thank you for your asssitance all.
Feel free to ask further questions.

 

[PedroUK]

I forgot to add that the 2 lighting will be fitted with fluorescent tube. I have not yet check the specifications I need to verify...

 

[Superspark23]

1. Run a 10mm² for about 15m from my consum unit to the edge of my internal house
run both ends into an double pole ac isolator so the swa can be safley isolated from both ends and corretly glanded

2. use an SWA armoured cable in a conduit which will be burried under 500mm (including tape at around 200mm depth indicating that electric cables are run underneath)
you dont need to run this in conduit as the steel armour is your mechanical protection

3. run adjacent to this cable (1 foot away) another conduit including CAT5e solid cable + perhaps cable for alarm system monitored 24H by ADT.
I dont know much about data installations

4. Use a consum unit (2xMCB for lighthing + 2xMCB for 2 ring main including in each room 3 to 4 socket-outlets [office room+garage] + 1MCB for interior electric heating [1kW] + 1 MCB for exterior electric heating [1kW])
I would keep all the lights on one 6a 1.5mm circuit, and 1 4mm radial 32a circuit for your sockets and spur of the radial for your heating corectly fusing down using switch fused conection units

5. 2 independant lighting circuit with 2.5mm2 cable
Why 2.5mm?

6. 2 independant wiring circuits [garage + room] with 2.5mm2

7. All socket-outlets in garage will be with built-in RCDs and be of type metal clad
i would use RCBO's
8. 2 FCU SPUR to connect to the electric heathers
Taken off a 4mm radial
9. 1 FCU Spur to connect to an external socket outlet water proof (IP55+)
You dont need to spur this

10. 2x 1way switches for the lighting

11. All circuit will be in conduit in the garage room.
Keep your data cables segregated from the 230v power

12. All circuit will be wired standard in the office (4662 boxes with plaster around)


13. The total surface of the garage is 29m2 (build reg exemption) so in term of lenght of cable, it could be up to maximum for a loop to wire both room together for socket-outlet around 25-30m.

Therefore knowing all the above I have a few questions:
1. Is 10mm² sufficient? Bearing in mind that one top of the heating I may run washing machine
10mm should be ok
2. Would anyone know the type of cable to use for ADT
Not sure
3. under the wiring regs, would CAT5e requires any additional precaution such as armoured? even if I use conduit?
Not sure, but if you want to stop some one putting a spade in it i would use steel conduit

4. How about the earthing? Does it need to be taken down on a stick next to my garage?
This depends on your zs value if its too high you would need to stake it and turn it into a tt

5. Is the number of MCB too much? Do I really need to have 2 lighing circuit for both rooms?
you would want 6a RCBO and a 32A RCBO and a main switch in a 2 way consumer unit correctly ip rated

6. Again can I have one large wiring ring to cover both rooms of that same building?
Yes but i recomend an radial for this installation

7. for 5. and 6. if one is sufficient for circuit required what would be the rating to take for MCB and short-cirucit capabilities? (6kA, 10kA 10A-20A...)
This depends on your PFC but 6ka is normally sufficiant in domestic situations

You've asked a lot of questions maybe you should get an fully qualified electrician in to do the work. Besides it has to be inspected and tested and the only person who can do that is the installer under part p of the building regs.

 

[SirKit Breaker]

Pedro,

by the content of your post it is obvious that you aren't a numpty, so i wont treat you as one.

The Electrician who is going to certify your work, can only do so if he has designed, installed and tested it. If you have found someone to certify it as you say in your post, then you will need him to carry out various tests on your supply to ensure that the equipment and material selected are suitable. he can also do the calculations for loading and volt drop to ensure you use the correct size of cables, he will also advise you of the best way to split up your circuits to give minimum disruption in the event of a fault.

I have no problems with people doing this type of work themselves, and have overseen a few jobs done by competent DIY people with no problems.
So the best advice i can offer is to get some professional help and guidance, the cost will far outweigh itself if it stops you cocking it up at the design stage.
This is a job which is too involved to give a definitive answer to in a forum, it needs seeing first.

Cheers.......Howard

 

[Superspark23]

I forgot to mention in your house consumer unit put this on a 32a Type s RCBO. this will save you from having to go into the house to reset the rcbo every the power trips out.

 

[ukpablo]

i agree with howard..................also is the main board that u are feeding the garage cct to have RCD protection, because if so u will have a problem with discrimination if u are fitting rcd devices in ur garage! just a thought!
good luck anyway.

 

[PedroUK]

Thanks ukpablo and superspark, I think your recommendation to use an Electrican happy to assist me for this work could be a good option and he may end up doing it fully for me anyway.

 

[sparky3366]

As regards to the cable for ADT. If it is a Galaxy panel, run a 4 core belden to the garage. If it isnt a Galaxy panel, run an 8 core alarm cable.

 

[72-van]

HI All
Just a thought why not just use a pair of these to make life easier for the data?
Clearly they are not as good as a "proper job" but for home use theyre ok that said i have seen them getting used in a summerhouse in someones garden that had three full time office staff running a plumbing bz..

85MBPS POWERLINE ETHERNET ADAPTER Plug and Play Fast UK on eBay (end time 04-Mar-11 22:16:38 GMT)

OR..just use a wireless router ((with secure encyption )) very cheap to set up and appropriate recievers on your pc /printer /laptop etc .

cheers 72-van

 

[PedroUK]

Thanks 72-van but I understand that you need to plug these 2 on the same power cable (e.g.10mm2) to receive good signal. The problem with it is my data is coming from another power line source which make me think that it may not work correctly. At least this is what a guy from IT told me this week.

 

[72-van]

Hi Pedro
In thruth thats what i have always been told about these ethernet plugs BUT it was clearly working in that summerhouse job i did .With one being plugged into a ring main in his house and the other on a circuit fed from armoured out to his ring main in the summerhouse/office. Over 50ft i would guess

If the It lad has a set ask to borrow them and try them on two seperate power circuits.I have even seen these used once by a local council in an old building were getting a fresh data feed to the particular location would have been very difficult to do ..

Having said all this fast & secure wireless is easy to do these days and very cheap.
cheers 72-van

 

[PedroUK]

thanks, seems interesting enough to investigate...I can buy it and if not happy return it anyway I suppose. I check this option. Thanks again.

 

[Superspark23]

all the cables join up in the consumer unit so the only issue i can see with them is the distance and resistance of cable may interfer with your signal strength.

 

[hsuelec77]

isnt it true that having a high zs reading on a circuit can be rectified by installing an rcd, so why install a earth rod for the garage, unless other services were installed such as water etc, but these days you would keep the water supply plastic through out, not requiring a main bonding conductor and all heating is electric.

 

[Hawk81]

I forgot to mention in your house consumer unit put this on a 32a Type s RCBO. this will save you from having to go into the house to reset the rcbo every the power trips out.

This will only be possible if the 10mm T+E is run in such a way to allow. Otherwise it will have to be on a 30mA RCD