Can we use the armour of an SWA as the CPC???

[i=p/u]

when reading the table lenny posted , doest st mean strands and cu as ccc

 

[tony mc]

St is the actual steel armour csa

Cu is the copper equivalent csa

 

[i=p/u]

so 1.5mm phase conductor in swa has 15mm csa swa as cpc and 6.65 equivelent in copper.. if im on right track

 

[tony mc]

Yes you are and thats for 2 core swa.

 

[i=p/u]

good man, wont have to ask again, stuck

 

[mattd888]

I have a similar table that the niceic sent me. Another point is that although the armouring is suitable for the circuits cpc it would be important to remember that it my not satisfy the requirements for bonding of water pipes etc if the armoured was a sub feed. Rotting of the armouring can be an issue but that is why a periodic inspection is/should be carried out to catch such issues before it completly breaks down.

 

[BARK982]

The armour of swa should always be connected to earth and that's why you don't have to rcd protect a swa because if you damage it you will hit an earth before a live conductor, thats why you don't see a lot of two core swa about because people stopped buying it and just using the old yellow or new black as the earth. But the cross sectional area of the swa is larger than the earth conductor inside the cable, but why not connect both.

 

[johnny999]

This is the reason why we were taught at collage not to use it!!

 

[malcolmsanford]

This is the reason why we were taught at collage not to use it!!

You have been taught in a college never to consider using the armoured of a SWA as the CPC?

 

[Engineer54]

You have been taught in a college never to consider using the armoured of a SWA as the CPC?

The mind just has to boggle at some of these so called competent to teach Electrical lecturers these day's.

 

[malcolmsanford]

The mind just has to boggle at some of these so called competent to teach Electrical lecturers these day's.

I know mate I sometimes just can't believe what is happening to our industry.

Not this young lads fault but the institution.

Apparently teaching someone to run a cat cable and terminating a RJ45 plug is considered more relevant to an electrician than running and terminating MICC.

 

[johnny999]

Sorry guys that was taught, it can corrode or come loose in the gland therefore not giving adequate continuity.

 

[malcolmsanford]

Johhny your quite right it can corrode in certain environments and of course it can come loose.

But IMO you should be taught all types of erection methods. I may very well feel as the designer that running an SWA in a ship yard or perhaps a chemical store will most likely have a corrosive affect on the armour. But if that was the case I would be looking at another method, perhaps galvanized trunking/conduit or even sheathed MICC, but if SWA was the best method then yes I would most likely run a 3 core using the 3rd core as your CPC.

As for the remark about it maybe coming loose well you could say that about any form of termination even the 3rd core of your SWA in a screw terminal.

I just feel that by blanketing use of "always using a 3rd core of a SWA as a CPC" is depriving you the student of designing an installation that is safe and the best for it intended use, as well in a lot of cases it's most cost effective.

 

[johnny999]

I think the course I was on ( 3yrs @ 1 day a week ) was symptomatic of the way this country has gone in the last few years, "keep it simple & go heavy on the Health & safety". I have lots of questions to ask which most of you will roll your eyes at.

 

[Guest123]

I think the course I was on was symptomatic of the way this country has gone in the last few years, "keep it simple & go heavy on the Health & safety".

In a nutshell.

I am astonished that you have been taught in this fashion, rather than outlawing it due to possible deterioration, they should be showing you how to install it in order to protect against the problem.

I despair, I really do!!!!:mad2: