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Topic Title: Part P AD 2013
Topic Summary: When is a CU change NOT a CU change?
Created On: 01 February 2013 02:18 PM
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 01 February 2013 02:18 PM
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mark2spark

Posts: 1444
Joined: 15 November 2006

According to my chat with a BI this morning, if you don't change the outer casing of a CU, and just introduce new 'guts' like a new busbar holding MCB's etc........ then it's not notifiable!

Wow

There doesn't appear to be much work that is notifiable now then? Why do a new circuit when you can spur off the existing is what the 5 dayers will say.
The point of being registered with a body is becoming stretched.

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I am prone to talking complete bol***ks at times, please accept my apologies in advance.
 01 February 2013 02:21 PM
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mark2spark

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I mean he was saying that you haven't 'replaced' it have you? That's the wording of the new AD 2013, Replacement of a CU. Not upgrading.

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I am prone to talking complete bol***ks at times, please accept my apologies in advance.
 01 February 2013 02:32 PM
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OMS

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Well, you know how the saying goes - the cutting edge of worst practice is about two steps ahead of regulation.

regards

OMS

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Failure is always an option
 01 February 2013 02:34 PM
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AJJewsbury

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Presumably if you're changing the characteristics of the protective devices (why else would you be changing the guts of it?) then you'd be creating lots of new circuits (if re-using lots of original wiring), so it would still be notifiable on that score?
- Andy.
 01 February 2013 03:14 PM
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rocknroll

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According to my chat with a BI this morning, if you don't change the outer casing of a CU, and just introduce new 'guts' like a new busbar holding MCB's etc........ then it's not notifiable!


A number of these points were discussed by some of us during the information sessions last year with regard to the proposed new document and the many loopholes that if you are bright enough could exploit.

If you rewire a property and do not add any extra circuits nor change the consumer unit do you notify.??

If you change say a 30A fuse for a 32A MCB are you really changing the parameters of the circuit or are you applying the building regulations definition of like for like, 'replacement with a comparable component or assembly'??

I will leave you to ponder over this for now.

regards

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"Take nothing but a picture,
leave nothing but footprints!"
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"Oh! The drama of it all."
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"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
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 01 February 2013 03:40 PM
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sparkingchip

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Remember the old saying "The blind leading the blind" and don't get caught up with a building inspector who doesn't understand the implications of what is being said.

Andy
 04 February 2013 04:58 PM
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mark2spark

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Once again, I don't think the BI's are interested Andy, if they know that you are a spark in some sort of guise then they really aren't bothered, they are only on the lookout for DIY'rs who might be chancers IMO.

Some good points there R & R

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 04 February 2013 05:12 PM
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AJJewsbury

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If you change say a 30A fuse for a 32A MCB are you really changing the parameters of the circuit or are you applying the building regulations definition of like for like, 'replacement with a comparable component or assembly'??

Well, since you ask...

In days of yore, up to 5s disconnection time was permitted for sockets (using the alternative method of limiting R2) - so loop impedances of up to 2.64 Ohms would have been permitted for a 30A BS 3036.

If you replace that with a B32, if Zs happens to be over 1.44 Ohms, then you've no guarantee it's going to open magnetically at all, and the thermal side might not kick in for more than 10 seconds.

These new fangled MCBs aren't always an improvement....

- Andy.
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