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Topic Title: 16mm t&e supplying house,main protective bonding?
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Created On: 02 November 2013 02:43 PM
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 02 November 2013 02:43 PM
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hertzal123

Posts: 277
Joined: 26 August 2007

A customer has requested a cu change in the above house.The t & e
is on a overhead from a detached building.The supply is tns.If I use the equation to prove the cpc is adequate,can the 6mm cpc in the cable be used for main bonding.I think the switch fuse at the supply is
a 63A bs88.Thanks for any advice.
Hz.
 02 November 2013 06:49 PM
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24Hour

Posts: 171
Joined: 06 April 2006

Whats the short circuit current , or zs at db?
Whith this info u can work out withstand

-------------------------
Yes i do do 24/7 everyday of the FLAMIN year.
 02 November 2013 11:37 PM
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hertzal123

Posts: 277
Joined: 26 August 2007

Originally posted by: 24Hour

Whats the short circuit current , or zs at db?

Whith this info u can work out withstand


Hi 24hr,
Will find out on Monday;
Thanx.
 03 November 2013 03:43 PM
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24Hour

Posts: 171
Joined: 06 April 2006

I just re read your question, if you are usung the 6mm in the t+e then u need to run a seperate earth 10mm.
If no bonding is req then the 6mm should be ok but subject to adiabatic equation of course.

It maybe cheaper/better to add a plastic insert if its water you need bonding.

-------------------------
Yes i do do 24/7 everyday of the FLAMIN year.
 04 November 2013 08:32 AM
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hertzal123

Posts: 277
Joined: 26 August 2007

Originally posted by: 24Hour

I just re read your question, if you are usung the 6mm in the t+e then u need to run a seperate earth 10mm.

If no bonding is req then the 6mm should be ok but subject to adiabatic equation of course.



It maybe cheaper/better to add a plastic insert if its water you need bonding.

Just thought the 6mm cpc in the submain was large enough fo mpb
if the supply was tns,but maybe not.
Regards,Hz.
 04 November 2013 12:20 PM
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AJJewsbury

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What's the (required) size of the overall installation's earthing conductor? - i.e. on what supplies the 63A fuse from the DNO's kit. Main bonding sizes should be referred to that.
- Andy.
 04 November 2013 01:52 PM
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Parsley

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As Andy as stated the bonding conductors will need to be sized with reference to the earthing conductor. the bonding conductor CSA must be at least half of the earthing conductors required CSA, 6mm is the minimum allowable CSA for a non PME installation bonding conductor.

The DNO's will probably want a minimum of 10mm2, UKPN consider TNS as being PME anyway.

Regards
 05 November 2013 07:15 PM
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hertzal123

Posts: 277
Joined: 26 August 2007

Originally posted by: AJJewsbury

What's the (required) size of the overall installation's earthing conductor? - i.e. on what supplies the 63A fuse from the DNO's kit. Main bonding sizes should be referred to that.

- Andy.

The switch fuse has a 10mm earth lead,but I am going to suggest a new 25mm overhead swa and 80A/100A fuse,,since the customer now wants a 10kw shower!

Thanks for all the advice,
Hz.
 06 November 2013 07:24 PM
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lyledunn

Posts: 582
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So you are going to rip it out? Not if it was my house, I have my golf club fees due and even if I hadn't I have better things to do with my money. How is that for a well considered engineering judgement?

-------------------------
Regards,

Lyle Dunn
 06 November 2013 08:22 PM
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OMS

Posts: 18919
Joined: 23 March 2004

golf club fees


Waste of a good walk, Lyle - but I agree that ditching a 16mm2 T&E submain in a domestic property is just a tad brutal in terms of a solution

Based on the OP comments, it sounds compliant with BS 7671 to me

Regards

OMS

-------------------------
Failure is always an option
 06 November 2013 09:37 PM
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Fm

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Joined: 24 August 2011

Likewise dont see the attraction
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