Best option going forward. Install cert.

[JohnW2]

EFLI has seemingly 'singled out' bonding, whereas 132.16 requires both bonding and earthing to be 'adequate' (before work is done), and one has to decide what 'adequate' means. A (TN) earthing arrangement which is 'adequate' today will presumably, in most cases, not be 'adequate' once "the 18th" is in force, at least with one interpretation of 'adequate'.

 

[ban-all-sheds]

Explain how at any point in time regulations can rely on earlier versions being available to the designer/installer/inspector/tester.

If work is being done to the N edition, then the only definition of "adequate" which can be used is that in the N edition.

As I said earlier, if the CU you are installing is to rely on ADS, then the ADS requirements which have to apply are the current ones, and to answer your earlier question 411 is the section which lays down the requirements which relate to ADS, and those requirements include protective earthing and protective bonding.

It would be unworkable for 132.16 to mean that earthing and bonding could be in accordance with requirements from past times.

 

[JohnW2]

So, as I asked, why did EFLI single out just bonding as something which "could [not] be in accordance with requirements from past times", when the reg to which you refer speaks of earthing in the same breath? ... and nor is this academic - bonding requirements have not changed for a good while, and aren't about to change, but the requirements for earthing are about to change.
As I therefore asked, do people believe that, come the 18th (assuming it remains true to draft), it will be the case that no work ('additions or modifications') will be able to be done in a TN installation without first installing an earth rod?

 

[ban-all-sheds]

Do we know what the 18th will say about the provision of a rod?

 

[securespark]

Can't find DPC any more.

 

[ericmark]

ADS simply means automatic disconnection of supply, it was EBADS the EB was earth bonding, but when the RCD arrived it was considered it could auto disconnect without earth bonding, so EB was dropped, however how this would help the guy get his installation certificate I fail to see?

 

[JohnW2]

542.1.201 The main earthing terminal shall be connected with Earth by one of the methods described in Regulations 542.1.2.1 to 3, as appropriate to the type of system of which the installation is to form a part and in compliance with Regulations 542.1.3.1 and 542.1.3.2. Additionally, there shall be an earth electrode, supplementing any earthing facility provided by the distributor, in accordance with one of the requirements of Regulation 542.2.3, to prevent the appearance ofa dangerous touch voltage in the event of the loss of the main connection to Earth.

 

[JohnW2]

ADS simply means automatic disconnection of supply, it was EBADS the EB was earth bonding, but when the RCD arrived it was considered it could auto disconnect without earth bonding, so EB was dropped

Was it not EEBADS ("Earth Equipotential Bonding and Automatic Disconnection of Supply")?

I never really understood (and still don't) what equipotential bonding has got to do with ADS and, since the primary mechanism of ADS is still mediated by OPDs, I don't think that the appearance of RCDs a good few decades ago had anything to do with "EEB" being dropped.

Kind Regards, John

 

[ericmark]

Yes EEBADS from memory this was ensuring enough current could run line to earth to operate the magnetic part of the trip, or rupture a fuse within the time limit. When the RCD arrived they would disconnect the supply without current high enough to operate trip or rupture fuse.

The fact it still required bonding to earth seems to have been missed, However question is do we actually require earth bonding for an RCD to work? Theory says yes, but we all know, on a non conductive floor, with shoes and socks on, standing on a wooden step ladder if you touch line you still get a shock, and it still trips the RCD.

For it not to trip, we would need to gradually charge our body to line potential.

 

[JohnW2]

Yes EEBADS from memory this was ensuring enough current could run line to earth to operate the magnetic part of the trip, or rupture a fuse within the time limit.

It surely is (and always has been) the installation's earth (and CPCs) that has to have a low enough impedance to ensure that the OPD operates in response to a fault (i.e. ADS), not the path to earth via bonded extraneous-c-ps. The path to earth (from exposed-c-ps) surely has to be low enough for ADS to work even if there are no bonded extraneous-c-ps.

Did 'bonding' perhaps have a different meaning in the days when "EEBADS" was coined?

When the RCD arrived they would disconnect the supply without current high enough to operate trip or rupture fuse.

Indeed - but, other than in TT installations, one is not meant to rely on RCDs for fault protection. BS 7671 regards RCDs as providing only 'additional protection' in a TN installation.

... but we all know, on a non conductive floor, with shoes and socks on, standing on a wooden step ladder if you touch line you still get a shock, and it still trips the RCD.

Eh? You'd surely be unlikely to get more than a 'tingle', at most (mainly due to capacitive coupling to earth), and there's surely no way that an RCD would trip?!

Kind Regards, John

 

[securespark]

Did 'bonding' perhaps have a different meaning in the days when "EEBADS" was coined?

Yes, it was popularised by Cynthia Payne.

 

[ban-all-sheds]

542.1.201 The main earthing terminal shall be connected with Earth by one of the methods described in Regulations 542.1.2.1 to 3, as appropriate to the type of system of which the installation is to form a part and in compliance with Regulations 542.1.3.1 and 542.1.3.2. Additionally, there shall be an earth electrode, supplementing any earthing facility provided by the distributor, in accordance with one of the requirements of Regulation 542.2.3, to prevent the appearance ofa dangerous touch voltage in the event of the loss of the main connection to Earth.

Hands up all those who think that t'committee simply did not think about the consequences of that and a requirement to ensure that earthing is adequate when there cannot possibly be any definition of "adequate" apart from "complies with {list of all regs imposing requirements for earthing}"?

And ditto all those who think that in Wiring Matters they will publish a piece explaining how the regulations don't actually mean what they can only mean.

 

[scousespark]

I know this thread stalled, but I'd be nterested to know how the op got on with his LABC.

 

[DetlefSchmitz]

Theory says yes, but we all know, on a non conductive floor, with shoes and socks on, standing on a wooden step ladder if you touch line you still get a shock

We performed this experiment under laboratory conditions, and nothing at all was felt.

 

[ericmark]

We performed this experiment under laboratory conditions, and nothing at all was felt.

Not sure how you can, in real terms you could select a random set of homes, where insulating foot wear, not welingtons as granite is added to mix to reduce static, and try holding the line wire.

However it is the very being in a laboratory which means the results are not valid. Around the home we have loads of items linked with inductive or capacitive bonds which you can't emulate in a laboratory, I only know of one job where the floor was tested, in a hospitial operating theatre special floors are used to reduce sparks because of gases used, other than there I have not seen floors tested.