Ne Consumer Unit

[Nijinski001]

Hi
I am a newly qualified 'Domestic Installer' and cold do with some more professional guidance. I am installing a new consumer unit no more than 20m from the mains. This will be from my main board in a dwelling to a shop below. Fed from this unit will be 2 lighting circuits and a socket ring.

What is the best method of connection to the main board?

I am considering
40a DP RCD unit
10mm cable fed from a 45a MCB to the new consumer unit. (Is this big enough?)
20a MCB for sockets (Heaviest load will include a fan heater at about 2.5Kw plus minimal appliances, clock, radio etc)
6a MCB for main shop lights
6a MCB for illuminated shop sign

Are there any other considerations you acn think of or anything I haven't considered?

Thanks guys

 

[ban-all-sheds]

Who said Part P would never work?

Hi
I am a newly qualified 'Domestic Installer' and cold do with some more professional guidance. I am installing a new consumer unit no more than 20m from the mains. This will be from my main board in a dwelling to a shop below. Fed from this unit will be 2 lighting circuits and a socket ring.

What is the best method of connection to the main board?

I am considering
40a DP RCD unit
10mm cable fed from a 45a MCB to the new consumer unit. (Is this big enough?)

It had better be, given that the shop CU only has a 40A incomer..
Where does the 10mm² run? I assume you've considered its rating given its installation method?

20a MCB for sockets (Heaviest load will include a fan heater at about 2.5Kw plus minimal appliances, clock, radio etc)

Might as well make this a radial.

Are there any other considerations you acn think of or anything I haven't considered?

As you're a registered Domestic Installer, does your PLI and PII cover you for working on installations in commercial premises? Do any of the shopkeeper's insurances specify a "full spec" contractor?

 

[Qedelec]

As this is a dwelling have you considered cooking or are the occupants going to go out for meals?

 

[Nijinski001]

Thanks for the reply.

I am now considering upgrading the unit for a 63A RCD rated CU and moving to 16mm cable. This is in case they decide to start adding anything.

I think I will stick with a socket ring circuit just in case they start adding things like microwave ovens etc.

The cable will be clipped direct T/E which according to my tables are rated 46a for 10mm cable and 62a for 16mm. Hopefully no-one disagrees with this?

The commercial/domestic issue has been broached with the shop keeper and he is comfortable. This is a bit of a rush job and I think he is stuck.

Thanks
+++++++++++++++++++++++
Hi Quedelec

The dwelling is separate and already fully wired. The shop is currently without power, hence the reason for the extension.

Cheers
________________________
moderator

please note 10a which is here

 

[Adam_151]

What about:

Tails into 80A metalclad switchfuse (both tails through same K/O), 16mm² 3 core SWA into MK 12 way metalclad CU, 100A main isolator, then split load kit and 80A 30ma RCD, you'll then be down to 8 ways, 4+4 split is probably best, 32A ring on RCD side, 6A shop lights on non-RCD side, not really sure about the shop sign, could probably be justified either way. Leaves plenty of room for expansion, if earth is TT, swap main switch for 100ma time delay rcd.

Obviously cable calcs will have to be done to make sure its acceptable

EDIT: I'm assuming its the standard 1PH 100A supply the DNO give to houses, etc

 

[ban-all-sheds]

The commercial/domestic issue has been broached with the shop keeper and he is comfortable.

It's not up to him...

 

[Spark123]

The cable will be clipped direct T/E which according to my tables are rated 46a for 10mm cable and 62a for 16mm. Hopefully no-one disagrees with this?

Table 4D5A, 10mm²T&E clipped direct = 64A, 16mm²T&E clipped direct = 85A (both before correction factors etc)

 

[keyplayer]

a newly qualified 'Domestic Installer'

What is this, and what can be done legally with this qualification?

 

[Steve]

What sort of shop is this? and what are "minimal appliances"?

 

[ban-all-sheds]

a newly qualified 'Domestic Installer'

What is this, and what can be done legally with this qualification?

//www.diynot.com/forums/viewtopic.php?p=153710#153710
//www.diynot.com/forums/viewtopic.php?p=153606#153606
//www.diynot.com/forums/viewtopic.php?p=153602#153602
//www.diynot.com/forums/viewtopic.php?p=153600#153600

 

[Nijinski001]

Thanks for the attention guys. I can draw a line under this one now but I'd just like to clarify and give answers to the last 4 or 5 posts.

Crafty1289 - Computer disposables small shop and small appliances are radio, telephone, kettle etc up to a max 2.5Kw heater in the winter.

Keyplayer - Domestic Installer is a qualification offered by a number of bodies. I did mine through a training companya nd certified by EAL. It is recognised by both IEE and NIC EIC and qualifies you to work on domestic dwellings as a 'competent person' and self certify under part P.
It does not qualify you as a fully fledged sparky.
See http://www.niceic.org.uk/partp/index.html

Spark123 - Thanks fo the correction. The table I was reading from is in the back of my local suppliers catalogue. I was also reading the values for 'enclosed in conduit'. This table reads 57A and 76A. There is still a discrepency I know. Thanks I'll refer to the official bible in future.

Ban all Sheds - I know it's not up to him. Bad choice of words. He has a sparky coming in on Tuesday to certify the installation and connect to the 3 phase incoming supply/distribution board.

Adam - Thanks for the solution. Weve gone for 16mm from the main board to a 80A standard CU. 32A RCBO and two 6A MCBs. It's 3 phase but I consulted with the guy who is coming to connect and certify and this was mainly his solution.

 

[keyplayer]

Sorry Ban, although in my name that last one wasn't actually my question. Must remember to log out on mates pcs! Very observant of you though. Poser is a kitchen fitter who just heard the letter P !