- Reaction score
- 2,115
Eh up
As per the title, "Is galv conduit containing insulated and sheathed cables (e.g. T&E) still an exposed-conductive part?"
Clearly, if it contained unsheathed singles, it obviously is.
If it's not an exposed-conductive part (and it's not extraneous in the case I'm thinking of) then it doesn't require earthing.
My gut instinct is that it's still an exposed-conductive part, but section 10.11 of GN8 - which is about cable tray, not conduit - got me thinking. That section (which refers to tray), states:
"A cable complying with the appropriate standard having a non-metallic sheath or a non-metallic enclosure is deemed to provide satisfactory basic protection and fault protection, as does an item of Class II equipment (Regulation 412.2.4.1 refers). Class II equipment is constructed such that any insulation fault in the cable cannot result in a fault current flowing into any conductive parts with which the equipment may be in contact. Hence, the metal cable tray or basket need not be earthed."
On the other hand, as insulated and sheathed cables are drawn into galv conduit, they may experience damage to their sheath which could not be spotted by inspection (they shouldn't get damaged if you do it carefully, but sometimes it happens). Hence my gut feeling of treating it as an exposed-conductive part. Which means an extra 4mm conductor for earthing it back to the MET (trivial to do).
Any thoughts, one way or the other?
As per the title, "Is galv conduit containing insulated and sheathed cables (e.g. T&E) still an exposed-conductive part?"
Clearly, if it contained unsheathed singles, it obviously is.
If it's not an exposed-conductive part (and it's not extraneous in the case I'm thinking of) then it doesn't require earthing.
My gut instinct is that it's still an exposed-conductive part, but section 10.11 of GN8 - which is about cable tray, not conduit - got me thinking. That section (which refers to tray), states:
"A cable complying with the appropriate standard having a non-metallic sheath or a non-metallic enclosure is deemed to provide satisfactory basic protection and fault protection, as does an item of Class II equipment (Regulation 412.2.4.1 refers). Class II equipment is constructed such that any insulation fault in the cable cannot result in a fault current flowing into any conductive parts with which the equipment may be in contact. Hence, the metal cable tray or basket need not be earthed."
On the other hand, as insulated and sheathed cables are drawn into galv conduit, they may experience damage to their sheath which could not be spotted by inspection (they shouldn't get damaged if you do it carefully, but sometimes it happens). Hence my gut feeling of treating it as an exposed-conductive part. Which means an extra 4mm conductor for earthing it back to the MET (trivial to do).
Any thoughts, one way or the other?