Garage Electrics, Consumer Unit - Which One?

[Ruffy]

Originally Posted by DarrenSV650S

Again, it comes back to how properly you want to do things. You could spend a small fortune just putting a couple of sockets in a garage.

OP wants to rewire an existing installation. If he didn't want to do it properly, why do it at all? The existing stuff probably still functions. If a major upgrade is needed due to safety concerns, is it not prudent to do it properly?

Of course, strictly speaking, you don't have to comply with Wiring Regs, as they're only a standard, not a statutory instrument. However, you do have to comply with Building Regs. Part P is most dominant section and you may struggle to get a LA Completion Certificate for a DIY electrical installation that doesn't comply with the Regs?

I agree about the cost point : Part P has added a lot of cost for little functional benefit in many cases

[yorkie_chris]

Or do it yourself safely and disconnect it if/when you want to sell the house.

When you say running tools off it, are you meaning a little electric drill, or a 200amp welding set?

[Ruffy]

Originally Posted by CarlosSV650S

You dont need to protect the sub main supplying the garage with an RCD as the unit that is going to be installed in the garage has rcd protection, PLUS your not supposed to have 2 RCD,s in stream. ( this is ok if you have a TN-S or TN-C-S system)

if you are going to take the cables for the sockets and lights for the shed directly from the house CU then you dont need an rcd in the garage like you said.

You may be right. For personal interest I will have to check the exact positioning requirements. My gut instinct is to wonder what happens if there's a cable fault (say a spade strike) - could still be left live without RCD in house.

You're right about 2 RCDs in line, unless the upsteam one (nearer source) is time delayed to maintain discrimination.

found this for ya.

Originally Posted by yorkie_chris

When you say running tools off it, are you meaning a little electric drill, or a 200amp welding set?

No, just the odd electric drill and/or mitre saw would be used.

Thanks to everyone for the required information regarding this update, and it has been pretty valuable.

I think the safest way would be to speak to a local "sparky" then move forward with a radial circuit for my requirements.

17th edition regs state that all circuits have to be RCD'd and not throught the main switch unless on a TT earthing system where the main switch will have a time delay.

your case you will prob's have a a TN-S system which means a new board in the house with a RCD for all circuit and the Garage circuit being on a time delay RCBO type C 30A disconnection with a 30mA trip.
The garage board should be an RCD main swtich with a 6A lighting circuit and a 20A radial circuit for the sockets, wire in 2.5mm for the sockets, the external socket wont need a fused connection unit if you want it wired directly onto the radial circuit. lighting you can use 1.0mm twin or 1.5mm twin.
the main house board will need an rcd before running the cable to garage by most council standards as it changes from council to council, most sparkys wont install it without an rcd in the main house.
i am a fully qualified sparky without all the being able to fill then certs in atm but noone asks for certs tbh.

Originally Posted by DarrenSV650S

What size of domino is protecting the garage supply?

Well it seems that a cable comes from the main cu, into another metal box with Coolex 30Amps written on it, then out the bottom another 10mm Grey cable going under the floor - and coming back up in metal conduit in the garage.

[Ruffy]

Originally Posted by CarlosSV650S

You dont need to protect the sub main supplying the garage with an RCD as the unit that is going to be installed in the garage has rcd protection, ...

Originally Posted by Ruffy

You may be right. For personal interest I will have to check the exact positioning requirements. My gut instinct is to wonder what happens if there's a cable fault (say a spade strike) - could still be left live without RCD in house.

Humble pie time: I can't find an absolute requirement to have an RCD at house end. However, if that is the case then the socket outlets in the garage need to be RCD protected.

Note to self - get properly to grips with the 17th Edition!

Originally Posted by CarlosSV650S

found this for ya.

Cheers. Where's it from BTW?

[Ruffy]

Originally Posted by slloyd

Looking to rewire my garage for new lighting and plug sockets, and want to replace the old grey type consumer unit with the current units they sell on the market now.

Just a little confused with these 2 models:-

http://www.screwfix.com/prods/63138/...-Consumer-Unit

http://www.screwfix.com/prods/33248/...-Consumer-Unit

Which one will provide me with basics for fluorescent lighting, and 6 internal double sockets, 1 external floodlight, and maybe a separate circuit for outside usage for lawnmower/pond pump?

The main consumer unit in the house, is the old rewireable type fuses that pull in/out and look like dominoes.

Should I upgrade this unit first, before changing the garage unit? or shouldn't it matter.

Thought I ought to answer your first questions.

1. The two units you link seem to be equivalent offerings from different manufacturers. Personally, I would buy the MK version, as I believe MK (and also Crabtree) are superior and worth the extra money. Either would be suitable for your application (Final ccts: 1 way lighting, 1 way power) unless you really want a separate circuit outside socket, which creates hassle fom a Part P standpoint.

2. In my opinion, I would upgrade the main consumer unit in the house first. This supplies everything electrical in your house, so it is a better safety investment to get rid of the rewireable board. It is a Part P notifiable job though, so you really ought to get a cert from somewhere. Perhaps best to employ a decent spark as it will probably be cheaper than trying to deal with LA directly anyway.

A question for you though. Do you really need to replace the whole garage system, or is an addition/alteration a better proposition? Might be more straightforward to carry out and also probably Part P non-notifiable

Originally Posted by Ruffy

Thought I ought to answer your first questions.

1. The two units you link seem to be equivalent offerings from different manufacturers. Personally, I would buy the MK version, as I believe MK (and also Crabtree) are superior and worth the extra money. Either would be suitable for your application (Final ccts: 1 way lighting, 1 way power) unless you really want a separate circuit outside socket, which creates hassle fom a Part P standpoint.

2. In my opinion, I would upgrade the main consumer unit in the house first. This supplies everything electrical in your house, so it is a better safety investment to get rid of the rewireable board. It is a Part P notifiable job though, so you really ought to get a cert from somewhere. Perhaps best to employ a decent spark as it will probably be cheaper than trying to deal with LA directly anyway.

Ruffy you are right and point 2 looks like the correct and safest way to move forward, and to avoid trying to cut corners where the power supply is concerned, so maybe saving the extra pennies to do it right 1st time around.

Originally Posted by Ruffy

A question for you though. Do you really need to replace the whole garage system, or is an addition/alteration a better proposition? Might be more straightforward to carry out and also probably Part P non-notifiable

Well the previous owner was a "DIYer" and seems to have the basics right, as the power and lighting continue to work. I just wanted to replace the single 40w bulb which is the only light source in the garage, to 3 x fluros, and tidy up the power sockets in 2 part trunking and increase the number available to me in order to have sockets available in most locations. I think it's just the untidiness of the wiring that makes it look worst that it is, and from what I can see from the "spagetti junctions" of wiring, it too looks like a raidial circuit.

I just wanted to tidy it up a little, and from the Periodic Inspection Report (IPM30) carried out last year, the electrician recommended for the electrics in this location to be improved to the current standards. I just wanted to do replace the garage power 1st due to the cost being considerably cheaper than changing the main consumer unit.