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help pls

Postby sulaiman » Fri Jul 03, 2009 7:55 pm

hi mate, can you pls have a look at my attached plan and tell me what you think for my brother's hep plsmechanic shop.

I am thinking of using 25mm Meter Tails Brown for L1, L2 and L3 from the mains to the switch gear, from switch gear to the Busbar, from the Busbar to the isolator and from the Isolator to the Distribution Board as shown in the diagram.

For the 2nd Distribution Board i am thinking of using a 3 Core Black Armoured to the Isolator and 25mm Meter Tails connect to the distribution Board.

This 2nd board is about 20m away from the Busbar, so what size of Armoured cable do you think i should use. I’m thinking of using 10mm cable.

I am going to ask an electrician to conect the switch gear to the mains for me.
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Simply Build It

Postby rosebery » Sat Jul 04, 2009 10:38 am

You should be asking an electrician to design, install, test and certify it all for you, frankly speaking.

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Postby sparx » Sat Jul 04, 2009 12:50 pm

Hi, no drawings attached but as this is commercial work it is covered by Electricity at work act.
& H&S at work act. both of which require 'competant persons to install, which by your questions you are not!
Cable sizing starts with expected load on final circuits and works back towards incoming supply to determine all cable sizes, taking into account ;
volt drop, earth fault loop impedances, supply external impedance Ze,
Prospective fault current etc.
These MUST be designed first, not built up as you go along.
You don't mention Neutral or earth sizes,
sorry but this kind of work is not for the DIY market, it needs design, testing during installation whilst circuits are dead, then further tests at switch on.
Best hope is to pay a good, qualified leckie to do design, agree to you running cables & him connecting and testing,
his design liability/professional indemnity/public liability insurances may then protect you if a problem occurs.
regards Sparx
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