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Topic Title: Extending earth bonding
Topic Summary:
Created On: 19 April 2017 01:04 PM
Status: Read Only
Linear : Threading : Single : Branch
 Extending earth bonding   - goldenboy1818 - 19 April 2017 01:04 PM  
 Extending earth bonding   - dustydazzler - 19 April 2017 01:32 PM  
 Extending earth bonding   - geoffsd - 19 April 2017 01:41 PM  
 Extending earth bonding   - weirdbeard - 20 April 2017 06:53 PM  
 Extending earth bonding   - mapj1 - 19 April 2017 02:08 PM  
 Extending earth bonding   - John Peckham - 19 April 2017 04:41 PM  
 Extending earth bonding   - geoffsd - 19 April 2017 05:03 PM  
 Extending earth bonding   - geoffsd - 19 April 2017 06:52 PM  
 Extending earth bonding   - mapj1 - 20 April 2017 12:25 AM  
 Extending earth bonding   - geoffsd - 20 April 2017 01:04 AM  
 Extending earth bonding   - spinlondon - 19 April 2017 09:22 PM  
 Extending earth bonding   - AJJewsbury - 19 April 2017 10:11 PM  
 Extending earth bonding   - mapj1 - 20 April 2017 01:38 AM  
 Extending earth bonding   - geoffsd - 20 April 2017 05:17 PM  
 Extending earth bonding   - geoffsd - 20 April 2017 07:07 PM  
 Extending earth bonding   - weirdbeard - 20 April 2017 07:22 PM  
 Extending earth bonding   - geoffsd - 20 April 2017 07:28 PM  
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 20 April 2017 01:38 AM
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mapj1

Posts: 12039
Joined: 22 July 2004

I think we are on the same page actually, though it may be that the insomnia, and a beer or two(*), is not helping the clarity - I agree, with an IJ in line there is precious little point in earthing the pipes specially back to the MET - after all any appliance connected to pipework within the building will have its own CPC, or be class II, and in any case a 10mmsq bond is then overkill for tripping the local breaker or RCD, now all that would be the most required.

The whole point was that without the IJ, assuming the pipes are electrically continuous and shared, then they bring it either the outside terra-firma potential via several, maybe many ohms in some cases, or nowadays more likely they bring in the integral of all the neighbour's neutral offset voltages via some tens to hundreds of milli-ohms if the road is on PME...

So the metal services are not really earthed, rather they are neutralled (avoiding using "neutralized" and "neutered" which may better describe the effects of the plastic mains and the relative the IJ on the slightly defunkt EEBADS concept.).

(* counting liberally, probably in decibels.+3 to +5 dBpints.)

-------------------------
regards Mike
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