For Fans of Bonding & Logic.

[EFLImpudence]

701.415.2 begins with:

"Local supplementary equipotential bonding according to 415.2 ..."

415.2.1 states "SEB shall include all simultaneously accessible exposed-conductive-parts of fixed equipment and extraneous-conductive-parts including ..."

It then states the formula R≤50V/Ia to determine if the parts are already adequately connected.

So, this means that if there are no exposed-c-ps then SB is not required - indeed, not possible.
Also people seem to forget the simultaneously accessible part.

All this is very clear and easy to understand.



However, back to 715.415.2 which, following the "according to 415.2" requirement then goes on to contradict, disregard and ignore 415.2 by stating that:

"(SEB) shall be established connecting together the terminals of the protective conductor of each circuit supplying ClassI and ClassII equipment to the accessible extraneous-c-ps, within a room containing a bath or a shower, including ..."

This is apparently a blanket requirement regardless of 415.2 (and must be done wherever the omission of SEB by RCDs etc. is not possible) because of the inclusion of ClassII circuits which have no exposed-c-ps and therefore, by 415.2, do not and cannot require SEB.
Other than this, it could have been argued that 715.415.2 only applied to parts covered by 415.2 in which case 701.415.2 would have been (unnecessary and) merely repetitive.



Does anyone see a need for bonding the CPC to ClassII items (this CPC may only be there as a requirement of 411.3.11 and 412.2.3.2 which states it is only for possible future requirement - a rather onerous demand if applied to other regulations)?
And:
Does the bonding have to be connected at the CPC terminals or would other equally adequate positions be satisfactory (if satisfying the electrical requirements)?
Or:
Does anyone think it is an OSG-like cover-all situation intended for those who do not really understand bonding?
Or:
Does anyone think this part of 701.415.2 is merely a badly written addition by someone with insufficient knowledge - much like some other bonding regulations - and should be, while not ignored, applied with superior knowledge?

 

[securespark]

Definite yes to the badly written bit. We have all waxed lyrical about the regs being difficult to interpret - the infamous Amd 3 being a perfect example...

Connecting at terminals seems to make sense, whether it be JB, ceiling rose, light switch, spur, DP switch etc..

CPC terminals appear at three places in the circuit, the origin, any joints and the destination.
Where else can you attach the CPC if not those?

Class II - don't think there is much point. As you say future-proofing is all well and good, but you can't do that across the board (no pun intended!).

 

[EFLImpudence]

Connecting at terminals seems to make sense, whether it be JB, ceiling rose, light switch, spur, DP switch etc..

CPC terminals appear at three places in the circuit, the origin, any joints and the destination.
Where else can you attach the CPC if not those?.

Ah. I thought it was only referring to the terminals at the appliance - I just wondered why it referred to terminals rather than connecting the exposed-c-ps.
Obviously, wherever it is connected there would be a terminal.

However, the point is that it says "of each circuit" whether or not it actually requires bonding under 415.2.


Not much point bonding at the CU terminal - but would people reading it realise that?

 

[securespark]

No, I agree, but it is included in the description.

The thing about SB is that it should not go back to the board.

"(SEB) shall be established connecting together the terminals of the protective conductor of each circuit supplying ClassI and ClassII equipment to the accessible extraneous-c-ps, within a room containing a bath or a shower, including ..."

Actually, it gets worse the more you read it.

Taken literally, that means the SEB should connect all the terminals of the protective conductor of each circuit.

Which is ridiculous.