I’ve been doing some reading on the above, and some seem to suggest that the swa should not be relied upon for the CPC, what is the generally consensus on here, my thoughts are it appears to still be listed in the BBB, and in my opinion in certain conditions I.e. indoors so no risk of rust due to poor termination should be fine and if glanced correctly gives appropriate readings.
543.2.1 (v) and 543.2.5 allows the metal covering including armouring to be used as a C.P.C. We use the armouring as a C.P.C. for street lighting, so it is not limited to indoor use only. You can always use a three core cable and use one internal core as a C.P.C. as well as the armouring for a single phase supply.
Perfectly fine to use armour as CPC, same as metal conduit - if it is going to corrode it is not installed correctly or it is the wrong cable for the location anyway.
However, the water is muddied with some smaller sizes of SWA, as the armour cross-section is not enough if for example you are exporting a PME earth to an outbuilding that needs bonding to plumbing or whatever. Also for some very large sizes, depending on circuit rating and length, Zs amy be too high.
No problem using the swa as the cpc for a basic final or submain circuit. It gets more interesting when the cpc/swa has more than one function.
Do the teachers at college still teach you to make off the glands correctly?
Legh
The evening we were taught how to make off SWA at college the head of department announced “Tonight your tutor is the workshop technician, because he used to work for a traffic light company and has made off more SWA than most people ever will”.
Thanks for the replies guys simply confirming what I had already thought, my investigation started after a comment was about it being unsuitable and can be used.
im sure I was taught correctly at college by an old hand lecturer however I’ve since since seen many various methods over the years, some more successful than others.
If you email me I will send you my paper on the use of SWA armour as a CPC. There are older versions of the paper available on various web sites but you may prefer the latest version.
Not as a couple of my young students who moved up through the college as apprentices said when asked by me what is the best lecture you have had in the college and replied, "When the college nurse showed us how to put a condom on a cucumber". I think this may have been a demonstration of making off glands other than in the college workshop.
Mind you I am still waiting for the opportunity to rescue a rubber brick from the bottom of a swimming pool whilst wearing my pajamas, as taught when I was at school. I carry a pair of rolled up pajamas in the boot of my car just in case the situation should arise.
