SWA seperate CPC

[paulthemagpie]

Hi guys,

how would you code a SWA cable which feeds a DB within a commercial unit with no seperate CPC so only realying on the SWA strands as means of CPC

 

[Andy78]

Hi guys,

how would you code a SWA cable which feeds a DB within a commercial unit with no seperate CPC so only realying on the SWA strands as means of CPC

Are you saying you have performed calculations which proves that the SWA is not sufficient for use as a CPC ?

 

[Spoon]

Hi OP.
What is the problem with it?

 

[davesparks]

Hi guys,

how would you code a SWA cable which feeds a DB within a commercial unit with no seperate CPC so only realying on the SWA strands as means of CPC

If it is only a CPC then it is almost certainly compliant (unless your testing suggests otherwise) with current regulations.

If it is also required to perform the function of a main bond then you will need to do further calculations and consider other variables to confirm that it is ok.

 

[Pete999]

Hi guys,

how would you code a SWA cable which feeds a DB within a commercial unit with no seperate CPC so only realying on the SWA strands as means of CPC

What size is the SWA is it 2 core 3 core or what, seem to recall that up to and including 95mm 2 core is the limit for using the steel as the cpc, I have a table somewhere giving details, but to busy at the mo to look for it, I got it from Google a while back try (pvc xlpe)

 

[davesparks]

What size is the SWA is it 2 core 3 core or what, seem to recall that up to and including 95mm 2 core is the limit for using the steel as the cpc, I have a table somewhere giving details, but to busy at the mo to look for it, I got it from Google a while back try (pvc xlpe)

Be wary of the tables floating around the Internet, they aren't exactly correct, more of a rough guide.
Calculation is the only real way of proving it

 

[Octopus]

Hi guys,

how would you code a SWA cable which feeds a DB within a commercial unit with no seperate CPC so only realying on the SWA strands as means of CPC

and the problem is? What is the Ze/Zbd?

 

[clematis432]

I personally dont like relying on the SWA although regs are quite happy about it. Always scared SWA comes loose on gland.
Are other forum members comfortable with only the SWA ?

 

[Andy78]

I personally dont like relying on the SWA although regs are quite happy about it. Always scared SWA comes loose on gland.
Are other forum members comfortable with only the SWA ?

I would be as comfortable and confident in using SWA as a CPC as I am in dressing in and making off SWA glands.

 

[clematis432]

And you never have a bad day ?

 

[Darkwood]

I personally dont like relying on the SWA although regs are quite happy about it. Always scared SWA comes loose on gland.
Are other forum members comfortable with only the SWA ?

Wouldn't your concerns be applicable to any earthing application, they are only as good as the method and means in which they are terminated and the competence of the person doing the termination, SWA glands are perfectly fine for the job, its down to the installer to ensure the glands (s)he fits do actually fit the cable correctly and are tight, and where required, an earth tail fitted to the earthing lug or bar.

 

[ipf]

And you never have a bad day ?

So you have a bad day and b***s things up and then just leave it without noticing, eh?

 

[Andy78]

And you never have a bad day ?

Well yeah we all do. I have made off plenty of glands I have not been 100% happy with. I have never left one not being sure of it's mechanical connection though.

 

[Risteard]

This question smacks of someone carrying out periodic inspection and testing without the knowledge and experience to be doing so. It's amazing how often people comdemn situations which are fully compliant with BS 7671.

 

[Risteard]

Be wary of the tables floating around the Internet, they aren't exactly correct, more of a rough guide.
Calculation is the only real way of proving it

Indeed - it's the difference between calculation and selection.