BS7671:2018 Proposed Changes

[hightower]

Anyone read up on the proposed changes to the next edition yet?

https://standardsdevelopment.bsigro...030342612?standardsReference=BS 7671#/section

Some interesting items in there.

 

[Andy78]

Yes, had a skim through them.
Nothing that will cause too much pain in the wallet for contractor or customer, or too much hassle on the install side.
I would like to know the justification for some of the mysterious new ideas though.

 

[hightower]

Well I suppose one of the biggest changes is the earth rod requirement for TN systems. I'm guessing it will be applied in a similar style to bonding requirements - no work to take place unless those are up to scratch - which is going to mean a fair old stock of electrodes in the back of the van.

 

[Andy78]

Well I suppose one of the biggest changes is the earth rod requirement for TN systems. I'm guessing it will be applied in a similar style to bonding requirements - no work to take place unless those are up to scratch - which is going to mean a fair old stock of electrodes in the back of the van.

Not sure about that one. The regs ask that the earthing and bonding be "adequate" before alterations take place. I'm not sure you can say that all earthing systems are now inadequate unless a supplementary rod is added.

 

[mattg4321]

What's the real world benefit of a rod on a TN-S system?

 

[hightower]

Not sure about that one. The regs ask that the earthing and bonding be "adequate" before alterations take place. I'm not sure you can say that all earthing systems are now inadequate unless a supplementary rod is added.

But they wouldn't be deemed 'adequate' in the eyes of BS7671:2018. I get what you're saying, how can something we've been doing/using for decades suddenly become dangerous overnight, but my argument is why include that regulation if they aren't going to enforce it somehow.

 

[mattg4321]

Further to my post on the other thread can anyone find anything about AFDD's and where they will be required, other than they may be fitted!

 

[Andy78]

But they wouldn't be deemed 'adequate' in the eyes of BS7671:2018. I get what you're saying, how can something we've been doing/using for decades suddenly become dangerous overnight, but my argument is why include that regulation if they aren't going to enforce it somehow.

It will probably be applied on new build.

the introduction of the regs states that older versions of installs need not upgrading just for the sake of it nor need be considered unsafe.

Who knows though ? We may be pushing rods in before we add a socket.

 

[Ian1981]

A rod would only make sense to me if it was tncs and it offered supplementary protection against an open pen conductor on the supply authority's cable

 

[Ian1981]

Further to my post on the other thread can anyone find anything about AFDD's and where they will be required, other than they may be fitted!

Hopefully the schemes and potential manufacturers will give information on these devices before bs7671 18th edition comes into force because personally I haven't a clue what they are in the sense of size, wiring specification and when they are to be installed as I'm sure we are all possibly in the same boat so technical advise is most welcome

 

[Ian1981]

Think we need not get too worked up over purposed regulations as this is only a draft copy and still around a year away so it's not worth losing sleep over it IMO

Obviously can't take my own advice as my previous reply post demonstrated

 

[davesparks]

Think we need not get too worked up over purposed regulations as this is only a draft copy and still around a year away so it's not worth losing sleep over it IMO

Obviously can't take my own advice as my previous post demonstrated

Yes it the draft for public comment, that's why it's important that we read and understand it so that we can make informed comments on it.

 

[davesparks]

But they wouldn't be deemed 'adequate' in the eyes of BS7671:2018. I get what you're saying, how can something we've been doing/using for decades suddenly become dangerous overnight, but my argument is why include that regulation if they aren't going to enforce it somehow.

It hasn't suddenly become dangerous overnight, the danger has been there, and been slowly increasing for many years.
The problem is broken PEN conductors, there was an article posted on here about it not so long ago.
A lot of our distribution system is somewhat antique with lots of new alterations and repairs with conversions to TNCS.

The requirement to install earth electrodes connected to the MET has been common in other countries for many years and its introduction here is a good thing in my opinion, but only if they get the regulations right with regards to Ra values.

 

[davesparks]

Further to my post on the other thread can anyone find anything about AFDD's and where they will be required, other than they may be fitted!

I don't think we'll get anything more than the 'may be fitted' in this edition, they will slowly become a requirement over the next few amendments.
I think the use of RCDs has followed a similar method of being brought in as a requirement

 

[hightower]

the introduction of the regs states that older versions of installs need not upgrading just for the sake of it nor need be considered unsafe.

But that all earthing and bonding must be up to standard. I'd read that as sticking an earth rod in aswell under these new rules.

It hasn't suddenly become dangerous overnight, the danger has been there, and been slowly increasing for many years.
The problem is broken PEN conductors, there was an article posted on here about it not so long ago.
A lot of our distribution system is somewhat antique with lots of new alterations and repairs with conversions to TNCS.

I understand the dangers with PEN conductors and how having an earth rod would reduce the risk, but why not just apply this ruling to TNCS? The draft says "supplementing any earthing facility provided by the distributor" - so why are they pushing it on TNS as well? Is it just to make sure they tick the boxes, so that any TNS that are later converted to TNCS for whatever reason will be covered?

 

[Ian1981]

It hasn't suddenly become dangerous overnight, the danger has been there, and been slowly increasing for many years.
The problem is broken PEN conductors, there was an article posted on here about it not so long ago.
A lot of our distribution system is somewhat antique with lots of new alterations and repairs with conversions to TNCS.

The requirement to install earth electrodes connected to the MET has been common in other countries for many years and its introduction here is a good thing in my opinion, but only if they get the regulations right with regards to Ra values.

Yeah I posted it after receiving an email from the electrical safety council.

 

[Ian1981]

But that all earthing and bonding must be up to standard. I'd read that as sticking an earth rod in aswell under these new rules.



I understand the dangers with PEN conductors and how having an earth rod would reduce the risk, but why not just apply this ruling to TNCS? The draft says "supplementing any earthing facility provided by the distributor" - so why are they pushing it on TNS as well? Is it just to make sure they tick the boxes, so that any TNS that are later converted to TNCS for whatever reason will be covered?

I love how the supply authorities issue becomes the installers problem!

 

[davesparks]

I understand the dangers with PEN conductors and how having an earth rod would reduce the risk, but why not just apply this ruling to TNCS? The draft says "supplementing any earthing facility provided by the distributor" - so why are they pushing it on TNS as well? Is it just to make sure they tick the boxes, so that any TNS that are later converted to TNCS for whatever reason will be covered?

I assume it is due to the widespread conversion of TNS services to TNCS.
I'm not sure that there will be many TNS services out there which are fully TNS these days.
Plus TNS isn't perfect and can suffer from a loss of its earth connection.

 

[static zap]

t ...AFDD's ....

If clever enough should be good , but if noise is external to
premises , could be back to "Nuisance value !"
(with less AM radios about , some are less aware of
consequences of gentle buzzing noises ! )

 

[Risteard]

Most of the rest of the world has required Earth electrodes on TN-C-S systems from year dot. It's about time it was required by BS7671.