My new house outdoor electrics changes

[quenchmaster]

Hi all,

I have been reading many comments about installs for garages and external appliances and have drawn from these and a couple of books I have here to come up with the plans for some alterations to the outdoor electrics.

Now before you say, Part P, Part P, Part P..... yes I know and the document discussed here is going to be part of my submission to my LABC as it is notifiable work. Although I am not a registered part p installer or done a C&G course I have done a 4 year degree in Electricity and Electronics so I do know what I am doing - to a point and hence why I am posting this.

I need to know if my document is up to scratch. I have the key points
eg voltage drops, loads, SWA, etc but I may have missed something. I also may need to change or add things.

The information is too long for a post so I have created a PDF of the document. It can be found http://www.adriangame.co.uk/ElectChangeHouse.pdf

Lastly I have not provided any information about install in the garage except for the supply (im still thinking about it) and lastly there will be data lines to the garage in a sperate duct 54mm - these are low voltage but do they have to go on the plans?

Thanks in advance to those that do help and to those that throw scorn on DIYers - I could do this with out telling anyone, I am trying to keep to the law - and then again I am not a bottom of the rung DIYer

Oh and for those who were looking for electrical ducting - www.abplumbing.co.uk does a range of sizes - however I have no idea if they sell to consumers yet (this isnt an advert, i have nothing to do with the company, its just a resource i have found while researching the information about this install)

 

[breezer]

tip:

use 2 x 45 degreee bends , its easier than a 90 degree bend

question.

what is a delecated supply?
(i presume you used my keyboard and really typed dedicated)

 

[Lectrician]

No, if you are using cable duct and not pipe, the 90deg bends will be 'swept'.

Why 10amp MCB for outside socket? 20amp would be better - 2.5mm allows this.

Why 16amp MCB for socket circuit in garage? again, this is old school - 20amp would more suit.

Two flood lights on garage on 6amp breaker - pushing your luck a little, from experience you will have spasmodic tripping even though total load may be below 6amp.

No mention of cable install method in garage or accessory type - conduit and metal clad?

Without calcing the volt drop, 4mm seems too small to me, basing this on the 40amp protection, not the 26amp max load - at 26amp it is likely to be ok. I would go bigger if it was me - anticipated load can always increase.

Fit a larger CU in the garage.

Cable from outside socket on house - You say it will be chased down the wall internally and plastered over. You need to make sure this is in a 'safe zone' or bury more than 2" deep, run it in earthed conduit, use a cable of concentric construction etc etc. Basically, make sure you fit an accessory directly behind the socket to show there is a cable in the wall, and run the cable vertically down from this - A 20amp switch would be a good idea - you can isolate the socket then.

Your SWA colour coding is incorrect.

There is no mention of dead tests or live tests in your blurb - I would think the LABC would be more interested in that than anything else.

 

[quenchmaster]

Cheers for all your comments Lectrician, here is my addtional thoughts:

No, if you are using cable duct and not pipe, the 90deg bends will be 'swept'.

Will be using proper cable duct, so yes I belive the 90deg bends are swept

Why 10amp MCB for outside socket? 20amp would be better - 2.5mm allows this.

I was working on maximum power requirement that I woud need but yes I could put it up to 20A

Why 16amp MCB for socket circuit in garage? again, this is old school - 20amp would more suit.

Only gave these as they are whats included in the unit. I could change it I surpose.

Two flood lights on garage on 6amp breaker - pushing your luck a little, from experience you will have spasmodic tripping even though total load may be below 6amp.

I take your word for it but I am not talking high power lights. Again 6A mcb it is what comes with the garage CU

No mention of cable install method in garage or accessory type - conduit and metal clad?

read my comments in first post - I have not thought about this bit yet. I wanted feedback on the bits done so far.

Without calcing the volt drop, 4mm seems too small to me, basing this on the 40amp protection, not the 26amp max load - at 26amp it is likely to be ok. I would go bigger if it was me - anticipated load can always increase.

I am going to use 6mm - it is stated, i was just saying that 4mm could do it. See http://www.tlc-direct.co.uk/Products/SW4slash3.html and http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

Fit a larger CU in the garage.

Show me where you can get IP55/IP56 or IP66 rated garage units that are larger and I might consider it but I dont think its necessary.

Cable from outside socket on house - You say it will be chased down the wall internally and plastered over. You need to make sure this is in a 'safe zone' or bury more than 2" deep, run it in earthed conduit, use a cable of concentric construction etc etc. Basically, make sure you fit an accessory directly behind the socket to show there is a cable in the wall, and run the cable vertically down from this - A 20amp switch would be a good idea - you can isolate the socket then.

I do say "needs to be protected with a cable cover", i was going to use
http://www.tlc-direct.co.uk/Main_Index/Conduit_Steel_Index/Capping_Steel_Galvanised/index.html but I will add the suggestions, although I am not sure I want a 20amp switch on the inside. The other suggestion I had was to run twin and earth to a joint under the floor, convert to a short bit of SWA to the outside and run the cables on the wall.

Your SWA colour coding is incorrect.

Not according to TLC: http://www.tlc-direct.co.uk/Products/SW4slash3.html if you still think thats incorrect tell me what is.

There is no mention of dead tests or live tests in your blurb - I would think the LABC would be more interested in that than anything else.

Yes i totaly agree, dead tests and live tests, but there wasnt any point doing this if people suggested major changes to what I had said

 

[quenchmaster]

tip:

use 2 x 45 degreee bends , its easier than a 90 degree bend

question.

what is a delecated supply?
(i presume you used my keyboard and really typed dedicated)

No, i ment dedicated, and wrote something completly different, which word then changed

 

[Cremeegg]

Another victim of TLC's outdated pictures on their website. You'll find its more like black grey brown although I'm surprised you hadnt picked this one up as its two plus years old

 

[quenchmaster]

So,

Brown - leave as is
Black - cover with green/yellow for earth
Grey - cover with blue for neutral

Would this be correct?

Its not just the fact that the picture is wrong, the text under it is half for old colours, half for new colours

i.e.

Brown is old Red (Live)
Black is old Yellow
Grey is old Blue

Discusses the changes in colours

Single phase wiring
Grey core is Sleeved or Taped with Blue for Neutral

Yellow core is Sleeved or Taped with Green/Yellow for Earth

Gets the gray correct, but the yellow incorrect - yellow not in harmonised colour system

 

[Lectrician]

Cheers for all your comments Lectrician, here is my addtional thoughts:

No, if you are using cable duct and not pipe, the 90deg bends will be 'swept'.

Will be using proper cable duct, so yes I belive the 90deg bends are swept

Good

Why 10amp MCB for outside socket? 20amp would be better - 2.5mm allows this.

I was working on maximum power requirement that I woud need but yes I could put it up to 20A

A socket should be able to supply the maximum load it can deliver - so should be atleast 13amps IMO, a typical 2.5mm radial socket cct will be rated at 20amps.

Why 16amp MCB for socket circuit in garage? again, this is old school - 20amp would more suit.

Only gave these as they are whats included in the unit. I could change it I surpose.

I have noticed these crappy CU's include 16amp MCB - Seems odd to me. a typical 2.5mm radial, as above, should be protected typically by a 20amp MCB.

Two flood lights on garage on 6amp breaker - pushing your luck a little, from experience you will have spasmodic tripping even though total load may be below 6amp.

I take your word for it but I am not talking high power lights. Again 6A mcb it is what comes with the garage CU.

I wouldn't increase the circuit rating, I would install two circuits if required. I was assuming 500watt floods.

No mention of cable install method in garage or accessory type - conduit and metal clad?

read my comments in first post - I have not thought about this bit yet. I wanted feedback on the bits done so far.

Fare enough Then thats my tip to you - spec metal clad and 20mm PVC conduit.

Without calcing the volt drop, 4mm seems too small to me, basing this on the 40amp protection, not the 26amp max load - at 26amp it is likely to be ok. I would go bigger if it was me - anticipated load can always increase.

I am going to use 6mm - it is stated, i was just saying that 4mm could do it. See http://www.tlc-direct.co.uk/Products/SW4slash3.html and http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

Dont forget voltage drop in the final circuits as well as the submain.

Fit a larger CU in the garage.

Show me where you can get IP55/IP56 or IP66 rated garage units that are larger and I might consider it but I dont think its necessary.

Always good to leave room for expansion. I would fit a 4 or 6 way metal clad if I was doing the job - why the need for an IP rated one?

Cable from outside socket on house - You say it will be chased down the wall internally and plastered over. You need to make sure this is in a 'safe zone' or bury more than 2" deep, run it in earthed conduit, use a cable of concentric construction etc etc. Basically, make sure you fit an accessory directly behind the socket to show there is a cable in the wall, and run the cable vertically down from this - A 20amp switch would be a good idea - you can isolate the socket then.

I do say "needs to be protected with a cable cover", i was going to use
http://www.tlc-direct.co.uk/Main_Index/Conduit_Steel_Index/Capping_Steel_Galvanised/index.html but I will add the suggestions, although I am not sure I want a 20amp switch on the inside. The other suggestion I had was to run twin and earth to a joint under the floor, convert to a short bit of SWA to the outside and run the cables on the wall.

You cannot use that cable capping as means of protection when installing cables outside safe zones. A nail will penetrate that just as easy as plastic or the cable. Earthing that capping is seen by some as adequate - It is not, for several reasons.

SWA in the wall would be fine, damage would still be done to cable if nailed, but the nail would cause overcurrent protection to operate. However, SWA into the rear of the socket is not a good idea - and if entering the bottom of the socket, you may aswell exit the house below floor level and then up the wall.

Your SWA colour coding is incorrect.

Not according to TLC: http://www.tlc-direct.co.uk/Products/SW4slash3.html if you still think thats incorrect tell me what is.

As your post above

There is no mention of dead tests or live tests in your blurb - I would think the LABC would be more interested in that than anything else.

Yes i totaly agree, dead tests and live tests, but there wasnt any point doing this if people suggested major changes to what I had said

I meant, you should end your blurb bay saying "After installation and before commisioning, the necessary dead tests required by BS7671 will be indertaken, the circuits will then be turned on and the necessary live tests done before the circuits are put into service".

Hope that all makes sense

 

[quenchmaster]

With regards to Lectrician's lastest comments.

Garage Conduit: 20mm conduit was what I was thinking. I assume that there is a reason for metal clad swt and sockets so I will use them. What would this be out of intreast, why not the normal plastic used in the house?

Voltage Drop: good point I hadnt thought of that. Wouldnt be much longer than 5 meters, but I will add it to calculations. On that point, how do you do voltage drop calculaitons for a length which covers two types of cable? i.e in this case SWA to 2.5mm do you just add the lengths togther?

CU for garage: I was basing the spec on what I had read on the site. I assumed it was a requirement for a dusty enviroment (its not going to get wet). I will look into it. My light circuits would require a larger CU going by your suggestions.

Outside socket: Will do the SWA method - it seems the safest. I did actualy mean come outside of the house below floor level and attached on the OUTSIDE wall - sorry I was being quick this morning when I replied.

Tests: Is that all you need to say. With regards to tests what should I do. I have got a socket tester but I assume other tests might be usefull e.g. insulation resitance. Earth checks etc. I will look again at BS7671 and my copies of the C&G sylibus.

With all that my last questions:
1)Some people have suggested an earthing spike into the ground at the garage end and connected to the earth from the SWA. Is this required/needed/stupid.

2)At the home CU end, if I need to get service blocks added. Is that the elec board or an electricians job? I assume the elec board as its coming from the meter.


Again cheers for all your comments