SWA cable , TT, do i need an earth conductor in the cable?

[vde-electrician]

At the origin the installation is TT.
Plan is to install a submain to a new db. Not carried out all the calcs yet, but my question is does the swa require an earth conductor in the cable.
Basically planning on running a phase and neutral or perhaps even 2 x phases and neutral.(the cable will be run long distance so thinking of reducing costs by not having a cpc conductor) I plan to rod at both ends and bond the swa sheathing at both ends. Providing my cable meets below the max zs for the mcb, the ze is permitted value, volt drop, and current carrying capacity, and backed up by the appropriate rcd to meet appropriate dissconnection times, am i complying?
For extra information the cable will be in the region of 70mm or 95mm at a guess, not yet calculated.

 

[Deleted member 9648]

Doubt you'll get a Zs for an OCPD. If you have an electrode at both ends then the (2 core)SWA armouring will just need earthing as a conductive part and will not be a cpc for the distribution circuit, it can however be used to link the two electrodes and will bring down the overall Ra. Use an S type time delay at the supply end.

 

[Strima]

Just use the armour as a CPC. Ensure it is not connected at the load end to maintain separation.

 

[Deleted member 26818]

As long as you don’t intend using the SWA as a bonding conductor, no you don’t need to use a core as a CPC.

 

[Deleted member 9648]

Just use the armour as a CPC. Ensure it is not connected at the load end to maintain separation.

It's TT at the origin, why separate?

 

[telectrix]

Just use the armour as a CPC. Ensure it is not connected at the load end to maintain separation.

i read OP as it's TT at origin, so Ze and hence Zs will probably be way too high for ADS.

 

[Strima]

It's TT at the origin, why separate?

Good point, I was raging at my NIC software at the time so missed that tiny, but pertinent, bit of information...

 

[Deleted member 9648]

Good point, I was raging at my NIC software at the time so missed that tiny, but pertinent, bit of information...

Are you trying to download Cliks new 18th software? Spent a torrid 2 hrs this afternoon only to find on finally getting there it wont run on the OS on the laptop I use on site.....(vista!!)….I know, ancient but it ran the previous version just fine. So after the 18th course, all the new books,now gotta buy a new laptop. How the ---- are we supposed to earn a living...……….

 

[Deleted member 26818]

Are you trying to download Cliks new 18th software? Spent a torrid 2 hrs this afternoon only to find on finally getting there it wont run on the OS on the laptop I use on site.....(vista!!)….I know, ancient but it ran the previous version just fine. So after the 18th course, all the new books,now gotta buy a new laptop. How the ---- are we supposed to earn a living...……….

Can’t you just buy a copy of Windows 7?

 

[Deleted member 9648]

Could do but I wouldn't want to do the install myself, by the time I've paid for the software and someone to set it up I may as well just get a new laptop with windows 10.

 

[Strima]

Are you trying to download Cliks new 18th software? Spent a torrid 2 hrs this afternoon only to find on finally getting there it wont run on the OS on the laptop I use on site.....(vista!!)….I know, ancient but it ran the previous version just fine. So after the 18th course, all the new books,now gotta buy a new laptop. How the ---- are we supposed to earn a living...……….

Is that still the Beta or the update?

Annoyingly it's going to cost my place around £600 a year with all the additional licenses. I'm tempted to start using Word templates, enough of being screwed over by various companies and CPSs...

 

[Nigel]

i read OP as it's TT at origin, so Ze and hence Zs will probably be way too high for ADS.

Not if the correct fault protection is installed, as it should be.

 

[Deleted member 9648]

Is that still the Beta or the update?

Annoyingly it's going to cost my place around £600 a year with all the additional licenses. I'm tempted to start using Word templates, enough of being screwed over by various companies and CPSs...

Cant download any new ecerts until V2 of the software is installed, and existing unused certs are not valid after the 31st. It did install ok but needs windows 7 or above to run. A call to Clik support confirmed. Should have expected it really as Vista hasn't been supported by MS for a long time, but the old software ran fine on the on-site laptop so no issues until now.

 

[vde-electrician]

thats great, just what i thought, thanks guys. One other thing, spinlondon mentioned not to use swa sheath as bonding. I understand because the swa sheath may not have the minimum surface area and thus minimum cpc would be too small. But say if the far DB had for example a 10mm onto a near by incoming water pipe, wouldn't this be classed as okay if the far db has its own rod , with correct size earth to it and a suitable loop reading? whats your thoughts?

 

[Deleted member 9648]

Minimum main bond for a TT is 6.0mm, so a main bond from the far DB with an electrode at that end will be fine.