Best practices

To me,  the question is very much one of how much danger really arises.

Consider these examples,   

1) a defective earth to a building with lots of folk in it all using portable appliances, (imagine a computer studies annex to a school ) 

and 

2) A situation with the same fault, but with no users and equipment where even if it fails in the most impressive way possible, there is no  or very little, electrical risk to life, but a nasty consequence to a false trip  (imagine perhaps a locked brick outhouse shed with sewage pumps in or something in it). 

In the former example, the odds that if the ADS is ever needed to fulfill it's purpose, someone, maybe many people,  will be on the wire at the time.  Meeting disconnection times and keeping touch voltages down is then paramount.

In the latter case you could probably have a live pump body for a week and so long as it kept on pumping, no-one would notice.  But you'd need to be aware if you unlocked the door that it may  not be as safe as it appeared, so boots & gloves perhaps.

So if the kit is running but not meeting the regs - do you label it in some way  as operational but with a known fault ?

Now BS7671 apply the same Zs (and therefore ADS operation time) to both, but  there is a world of difference between the severity of outcomes, and to quote Matilda “and  that's not right” Perhaps less strongly, it is not a balanced approach to the real risk.

Very tellingly, the DNOs have a very different set of rules, because in their case leaving the power on if at all possible is the more desirable case compared to turning it off - so they do not even isolate to do cable joints and cut-out replacements, if they can avoid it, and they won't blink at a 1megohm insulation resistance, or even 100k  in a long run of existing cable.

I venture to suggest that some types of installation could be safely treated in a more DNO like way, and even perhaps allowed to run to catastrophic failure with a known minor fault,  without troubling the scorers, so long as access to the possible dangerous bits is limited to folk who understand the risk and know what to look out for.

Whats not acceptable is exposing the ‘ordinary person’ who may be in flip flops and have a weak heart.

Mike.

"We're told we have to do as we're told but surely
Sometimes you have to be a little bit naughty."

Matilda again…

To me,  the question is very much one of how much danger really arises.

Consider these examples,   

1) a defective earth to a building with lots of folk in it all using portable appliances, (imagine a computer studies annex to a school ) 

and 

2) A situation with the same fault, but with no users and equipment where even if it fails in the most impressive way possible, there is no  or very little, electrical risk to life, but a nasty consequence to a false trip  (imagine perhaps a locked brick outhouse shed with sewage pumps in or something in it). 

In the former example, the odds that if the ADS is ever needed to fulfill it's purpose, someone, maybe many people,  will be on the wire at the time.  Meeting disconnection times and keeping touch voltages down is then paramount.

In the latter case you could probably have a live pump body for a week and so long as it kept on pumping, no-one would notice.  But you'd need to be aware if you unlocked the door that it may  not be as safe as it appeared, so boots & gloves perhaps.

So if the kit is running but not meeting the regs - do you label it in some way  as operational but with a known fault ?

Now BS7671 apply the same Zs (and therefore ADS operation time) to both, but  there is a world of difference between the severity of outcomes, and to quote Matilda “and  that's not right” Perhaps less strongly, it is not a balanced approach to the real risk.

Very tellingly, the DNOs have a very different set of rules, because in their case leaving the power on if at all possible is the more desirable case compared to turning it off - so they do not even isolate to do cable joints and cut-out replacements, if they can avoid it, and they won't blink at a 1megohm insulation resistance, or even 100k  in a long run of existing cable.

I venture to suggest that some types of installation could be safely treated in a more DNO like way, and even perhaps allowed to run to catastrophic failure with a known minor fault,  without troubling the scorers, so long as access to the possible dangerous bits is limited to folk who understand the risk and know what to look out for.

Whats not acceptable is exposing the ‘ordinary person’ who may be in flip flops and have a weak heart.

Mike.

"We're told we have to do as we're told but surely
Sometimes you have to be a little bit naughty."

Matilda again…