S.W.A. Armour Earthing.

gkenyon:

lyledunn:

gkenyon:

Zoomup:

Indeed, I noted the "deficiency" and am not entirely happy with the situation. It was installed on the cheap by a sports' club member. I was keen to learn of regulations that apply if I have to defend my position of criticising the installation.


Z.

As previous post - page 39 of GN3

With respect, that's not the point. Z was looking for a reference in BS7671 2018 itself. To invoke 411.3.1.1 one would need to accept that the armour is an exposed conductive part and the definition of exposed conductive part in part 2 would not support that determination. 

To avoid imagination stretch the normal practice would be to employ explicitness, which is clearly absent in BS7671 with respect to the issue of earthing the armour, other than for certain underground applications. 

Interestingly, in 522.8.10 of IS10101:2020 there is no explicit mention for the need to have the wire armour earthed in underground applications. However, 526.5.1 states "Adequate electrical conductance shall be provided between metal sheaths or armouring of cables and the earthing terminals of equipment. This requires proper design and a proprietary method"........."A cable gland is a proprietary method"

With respect also, I don't agree with you that the definition of exposed-conductive-part in BS 7671 'doesn't support that determination'

Exposed-conductive-part. Conductive part of equipment which can be touched and which is not normally live, but which can become live under fault conditions.

A cable is (electrical) equipment as defined in BS 7671.


The armour is a conductive part. It is not normally live.


As I've said, unless it is covered by insulation that can only be removed by destruction, it can be touched. The circumstances may change as to when it can be touched, but an electrician would not expect armour to be a live part ... CDM designer's duties come in here, for all installations including domestic.


BS 7671 isn't a manual, and it's been in the published guidance for some time.

I disagree. A steel wire armouring which is part of a S.W.A. cable can NOT be touched as it is protected by a heavy duty P.V.C. oversheath. Therefore it is NOT an exposed conductive part. It simply is NOT exposed.


If the cable in my case 2 has a copper core used as a C.P.C., then the regs. appear not to require the armouring to be earthed.



Z.

gkenyon:

lyledunn:

gkenyon:

Zoomup:

Indeed, I noted the "deficiency" and am not entirely happy with the situation. It was installed on the cheap by a sports' club member. I was keen to learn of regulations that apply if I have to defend my position of criticising the installation.


Z.

As previous post - page 39 of GN3

With respect, that's not the point. Z was looking for a reference in BS7671 2018 itself. To invoke 411.3.1.1 one would need to accept that the armour is an exposed conductive part and the definition of exposed conductive part in part 2 would not support that determination. 

To avoid imagination stretch the normal practice would be to employ explicitness, which is clearly absent in BS7671 with respect to the issue of earthing the armour, other than for certain underground applications. 

Interestingly, in 522.8.10 of IS10101:2020 there is no explicit mention for the need to have the wire armour earthed in underground applications. However, 526.5.1 states "Adequate electrical conductance shall be provided between metal sheaths or armouring of cables and the earthing terminals of equipment. This requires proper design and a proprietary method"........."A cable gland is a proprietary method"

With respect also, I don't agree with you that the definition of exposed-conductive-part in BS 7671 'doesn't support that determination'

Exposed-conductive-part. Conductive part of equipment which can be touched and which is not normally live, but which can become live under fault conditions.

A cable is (electrical) equipment as defined in BS 7671.


The armour is a conductive part. It is not normally live.


As I've said, unless it is covered by insulation that can only be removed by destruction, it can be touched. The circumstances may change as to when it can be touched, but an electrician would not expect armour to be a live part ... CDM designer's duties come in here, for all installations including domestic.


BS 7671 isn't a manual, and it's been in the published guidance for some time.

I disagree. A steel wire armouring which is part of a S.W.A. cable can NOT be touched as it is protected by a heavy duty P.V.C. oversheath. Therefore it is NOT an exposed conductive part. It simply is NOT exposed.


If the cable in my case 2 has a copper core used as a C.P.C., then the regs. appear not to require the armouring to be earthed.



Z.