Bonding conductor in armour?

[cornburn]

When running a new feed in armour, that will also require a bonding conductor over the same run, is there a problem with buying armour with an extra core and using one of those? I only ask as I've only ever seen a separate green and yellow zip tied to the side of the armour, if you're using 2 cores and the sheath as your earth, why not buy 3 core and use the other core as your bond?

I suppose it's meant to be unbroken and it would be rare in commercial setups that the armour going in is running from the MET right to where the services come in at the other end

 

[KINKY]

No problem with using a spare core as earth. Assuming its CSA is adequate for the purpose.

 

[IQ Electrical]

I suppose it's meant to be unbroken and it would be rare in commercial setups that the armour going in is running from the MET right to where the services come in at the other end

Do you mean as a cpc or a protective bonding conductor?

 

[cornburn]

As in the post, bonding conductor. Will be 3 phase + neutral so thinking 5 core and using one of the cores as the bond for gas and water and the sheath as main earth

 

[KINKY]

You have to run individual cables/cores for Main Bonding Conductors, dont you?

So a 6c SWA would be required.

 

[cornburn]

You have to run individual cables/cores for Main Bonding Conductors, dont you?

So a 6c SWA would be required.

This is what I need to look up. We're looking at a 16mm 3 phase feed, 50A per phase so I'm thinking might be easier to use 4 core 16mm for the 3 and neutral, sheath for the earth and a separate 10mm for the bond. Both services are within a meter of each other and the MET is about 40 metres away so don't want to drag another cable over there unnecessarily to bond each one separately. I can't find anything in the book stating that each must have it's own. I'm thinking trying to use a spare core (or cores) will be too much of a faff and waste meters of the other conductors as we'd have to cut them back to get the length for the bonding conductor.

 

[IQ Electrical]

Personally, I'd install a separate protective bonding conductor-you can pick up both services if the conductor remains unbroken.

This means that any future alterations to the 3-phase item still leave the main protective bonding intact.

 

[cornburn]

Thanks. This is what I've decided to do. I've just got to sort out my confusion over the sizing now as the PME coming in is massive compared to this submain - on another post http://www.electriciansforums.net/e...23491-sizing-bonding-subboard.html#post173423

Thanks for your help