please help, advice needed

[JACKC]

Sorry but you have been given lots of advise on this and they all point in the direction of trust your sparky.
Size of swa depends on load.
Plastic sockets or metal, depends on if your garage is full of crap or a you can use it for a car. Mine are all metal as its a store and things get chucked in.
Do cables need protecting, again is it likely to get damaged.
Personally I wouldn't let anyone do any work except dig a trench. You are asking for quotes, yes they are different because we all design different but we all sign it is to the regs and we are happy with it. Let the sparky do the work, you ain't going to save much as he will be checking everything you have done.
As BAS says, pick the cheapest if you are moving and want to save money. Save even more and don't do it, when you move its the new owners problem.

 

[Chri5]

What size swa would i need to buy?

.

On the assumption that you will have a 40 amp supply via main board then 6mm, but as mentioned a 10mm gives much better scope.

im also picking up the sockets and light fittings tomorrow,do these need to be metal clad? or will plastic backboxes etc be ok?

i will have 5 double sockets in the garage
2 light fittings, 2 x switches.

Top job would be conduit drops to metal boxes, horizontal wiring at height could be clipped on a batten.
The installation should be suitable for the environment, if its going to be a workshop then it needs to be up to the job.

Plastic conduit and fittings may be acceptable- only you know

do the cable need protection in form of metal conduit or can these be simply clipped to the walls? and through roof joists where required? .

See above

also picking up the consumer unit for garage including mcb's

what would be the best set up for the 5 x sockets, 2 x lights i will be using? if sockets are on a radial the length will be no more than 7 metres to the furthest socket(furthest from consumer unit). .

4mm TE socket radial or 2.5mm ring supports 32amp
1.0mm will support 6 amp lights

So at full tilt you might draw 38amp protected by a 40amp mcb at the main board.

also the consumer unit in the house which supply is coming from is sector, what size MCB should i buy ready for this end?.

See above

will i need anything else or will sparky simply terminate swa cable into both consumer units without the need to connect any t+e ?.

The swa HAS to be earthed on the armour, banjos or piranha nuts mostly via a metal earthed box adjacent to the board.

Could spec a metal clad for the garage, but not sure about small CU sizes in metal.

is 2.5mm cable sufficient for sockets and 1.5mm cable sufficent for lighting?.

See answers two back

many thanks for your help just need these few answers in order for me to supply the materials and run the cables ready for sparky to come in either end of week or monday to do connections and testing.

Earthing has NOT be discussed
RCD protection has NOT been discussed
Use of garage has not been discusses
Ancillary power requirements such as security lights, a jacuzzi and pond pump has not been discussed.


I don't dispute your claims, but what you are intending to get won't be cheaper, may well be wrong and doesn't consider the whole 'design' and 'installation' requirements.

Take the swa, how do you know the best route ? Will 6mm SWA feed through the old ug route, or will you go catenary (air) or new ug and down 30" ? The cost is on length which you don't know due to not knowing the route.

You know nothing of the rcd requirements, and haven't mentioned anything about the main board. Does it have the correct 25mm supply tails the 16mm MET, the earth bonding for the gas and water in 10mm.
If the main board isn't suitable it might be better to take the swa direct to the mains in feed and treat the garage as a seperate CU rather than a sub board.
The above was a bit of an attempt to justify why it's NOT a simple diy job.

Stick with the bits you know. Get some cable, do the garage carcass / 1st fix and hope that's good enough for the spark to accept.

I'd suggest switches and sockets (at a height that avoids car doors)
in plastic with plastic conduit drops from the ceiling line.
If required fix wood runners for horiz cable to clip to.

 

[1john]

all of these questions need to be answered by the sparky signing it off, if you go out and buy all this gear and then he says that it is not suitable then what is going to happen then? Also your sparky will get these materials for much less that you can!

 

[securespark]

Malc:


There is no discrimination in your suggested installation.

 

[ban-all-sheds]

ok ive made the decision to tomorrow go and buy some swa cable to run from the existing consumer unit to where the sparky will be fitting the new consumer unit.

have informed sparky im not prepared to use the exsisting cable due to being concerned with the state of cable which we can not see.

What size swa would i need to buy?

None - it will be cheaper to have your electrician supply it as he will get discounts at wholesalers and you won't.

If you insist on buying despite the fact that it will cost you money not save it, you need to buy the size your electrician specifies, because he is the one who you'll be wanting to sign an official document to say he designed it. The certificate you'll need when you sell the house is not just one to say that an electrician checked it over and it all seemed OK, it's an Electrical Installation Certificate, and the declaration on it reads (with my emphasis):

I being the person responsible for the Design, Construction, Inspection & Testing of the electrical installation (as indicated by my
signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the Design,
Construction, Inspection & Testing, hereby CERTIFY that the said work for which I have been responsible is to the best of my
knowledge and belief in accordance with BS 7671:2008....

Design includes choosing the sizes of cables. It doesn't matter what anybody here says - he is the only one who may tell you what size to go and buy.

im also picking up the sockets and light fittings tomorrow,do these need to be metal clad? or will plastic backboxes etc be ok?

That depends on your electrician's assessment of the environment with respect to Regulation Group 522.6. He is the one you'll be expecting to sign the declaration quoted above, so it can only be his knowledge and belief that matters.

do the cable need protection in form of metal conduit or can these be simply clipped to the walls? and through roof joists where required?

Ditto.

also picking up the consumer unit for garage including mcb's

For someone looking to save money you are doing some incredibly silly things.

what would be the best set up for the 5 x sockets, 2 x lights i will be using?

Ditto the comments about your electrician being the one you want to accept responsibility for the design.

also the consumer unit in the house which supply is coming from is sector, what size MCB should i buy ready for this end?

Ditto.

will i need anything else or will sparky simply terminate swa cable into both consumer units without the need to connect any t+e ?

Cant say without seeing it.

is 2.5mm cable sufficient for sockets and 1.5mm cable sufficent for lighting?

Ditto the comments about your electrician being the one you want to accept responsibility for the design.

many thanks for your help just need these few answers in order for me to supply the materials and run the cables ready for sparky to come in either end of week or monday to do connections and testing.

You see I think this is where you are fundamentally going wrong.

Testing is not enough.

You need a full EIC signed by an electrician saying that he did the design and construction as well as the testing, and you need a certificate from the council saying that it all complies with the Building Regulations. A registered electrician will self-certify compliance, but again I can't see anyone except a really dodgy cowboy agreeing to certify that he did things he didn't actually do.


I'm not taking the p*** with all the times above where I've said "ask your electrician" - that really is the way it has to work.

I know you said that all 3 contenders said that they were OK for you to do first fix, but did they actually agree to do anything more than testing? Did they agree that even if you made all the design decisions they would sign a certificate to say they did that, and did they agree that they would certify to the council that they did it all?

Because if not your plan to have certificates when you sell the house will crash and burn.

 

[ban-all-sheds]

Posted: 16th August 2010, 20:26

Rated: -1 Post Subject:

As im looking to sell this house in the near future i need all certificates up together.

Just pick the cheapest one.

As BAS says, pick the cheapest if you are moving and want to save money.

Strange, isn't it, how I picked up a thumbs down, and Jackc didn't.

Why - one might almost think that someone did it for reasons of personal animosity rather than for genuine reasons based on a logical and rational analysis of the post.

 

[riveralt]

ok ive made the decision to tomorrow go and buy some swa cable to run from the existing consumer unit to where the sparky will be fitting the new consumer unit.

have informed sparky im not prepared to use the exsisting cable due to being concerned with the state of cable which we can not see.

What size swa would i need to buy? .

Ask the designer of your installation- the person who is going to sign it of.

do the cable need protection in form of metal conduit or can these be simply clipped to the walls? and through roof joists where required? .

Ask the designer of your installation- the person who is going to sign it of.

also picking up the consumer unit for garage including mcb's

what would be the best set up for the 5 x sockets, 2 x lights i will be using? if sockets are on a radial the length will be no more than 7 metres to the furthest socket(furthest from consumer unit). .

Ask the designer of your installation- the person who is going to sign it of.

also the consumer unit in the house which supply is coming from is sector, what size MCB should i buy ready for this end?.

Ask the designer of your installation- the person who is going to sign it of.

will i need anything else or will sparky simply terminate swa cable into both consumer units without the need to connect any t+e ?.

Ask the designer of your installation- the person who is going to sign it of.

is 2.5mm cable sufficient for sockets and 1.5mm cable sufficent for lighting?.

Ask the designer of your installation- the person who is going to sign it of.

many thanks for your help just need these few answers in order for me to supply the materials and run the cables ready for sparky to come in either end of week or monday to do connections and testing.

By asking these questions you are just confirming that there is no spark involved and you are going to do the work yourself.

Unfortunately, the nature of your questions indicates you are quite incapable of installing this installation - so stop and seek expert help - not here but from a spark you trust.

If I am wrong, and I humbly apologise if that is so, then the spark you have chosen will give you the answers. Not us, here, because we do not have all the facts to give specific answers.

Your spark, after all, will have worked out all the calculations, cable runs and sizes in designing the installation - recognise the necessary supervision points (to check your doing it right) during the installation and determine when to test the system before issuing you and the LABC with the appropriate certificate.