Doing my first sub-main in SWA.

[ash2020]

I guess 16 will do, it's a smallish flat. I wasn't sure about being able to use the armouring for the main earth. Are you saying it's not enough? The calcs for it are mind boggling. (543.1.3 17th ed) How the hell do you work out the CSA of the armouring?
And is I in the equation the same as max PFC?

 

[Mike P]

I only use the armour as a way of beefing up the earth and mech protection.
If your not running three core 16mm yoy should run a seperate 16mm MET

 

[ms&electrical]

I only use the armour as a way of beefing up the earth and mech protection.
If your not running three core 16mm yoy should run a seperate 16mm MET

I would do it this way to. 3 core 16mm swa with 60amp switch fuse isolator.

 

[ash2020]

Sorry to bang on about it but where does it say about running a separate earth and why isn't the armouring sufficient.

 

[Spudnik]

Sorry to bang on about it but where does it say about running a separate earth and why isn't the armouring sufficient.

There is no requirement if you are using 3 core SWA, but obviously you need one if using 2 core plus seperate earth.

However, if there is no need for mechanical protection and it is going to be run in trunking, then i would suggest you ask your supplier for 16mm split concentric cable.

Doddle to run and terminate with standard plastic compression glands.

Have a look here:

Electrical Cable - Split Concentric Cable BS7870

 

[jibspark]

There is no requirement if you are using 3 core SWA, but obviously you need one if using 2 core plus seperate earth.

However, if there is no need for mechanical protection and it is going to be run in trunking, then i would suggest you ask your supplier for 16mm split concentric cable.

Doddle to run and terminate with standard plastic compression glands.

Have a look here:

Electrical Cable - Split Concentric Cable BS7870

wow! never seen that before! whats with all the neutrals???

 

[Spudnik]

wow! never seen that before! whats with all the neutrals???

The neutral conductors csa together form 16mm2. As the same with the CPC's.

Centre core is 16mm line conductor.

 

[sparkyork]

last time i used some of this stuff we had to heat shrink the neutrals and earth

 

[Spudnik]

last time i used some of this stuff we had to heat shrink the neutrals and earth

No need if they are terminated into an enclosure!

Plus, 10mm earth sleeve is available.

 

[sparkyork]

they were terminated into consumer units from sw/fuse isolators down in the mains room. both ends were heat shrinked, neatrals were carefully bared off and twisted together, and heat shrinked. looks professional, rather than seeing a load of seperate neautrals etc.

 

[ash2020]

D'you think it would be ok to run split con through a communal entrance hall (all indoors) into the flats without trunking, just clipped to the surface? If not, would plastic trunking be OK?

 

[spark-doctor]

Sorry to be the bearer of doom but if you used Split-Con you would have to RCD protect the cable, bury it greater than 50mm or protect it with earthed capping/conduit, as it does not have a earthed protector and the Neutral is classed as a Line conductor.

Trying to get all the neutrals into the termination would be a pain as well.

As for not sleeving them, would you not sleeve CPC and Neutral conductors in a CU?

 

[Spudnik]

Sorry to be the bearer of doom but if you used Split-Con you would have to RCD protect the cable, bury it greater than 50mm or protect it with earthed capping/conduit, as it does not have a earthed protector and the Neutral is classed as a Line conductor.

Trying to get all the neutrals into the termination would be a pain as well.

As for not sleeving them, would you not sleeve CPC and Neutral conductors in a CU?

There is no requirement to rcd protect a split con cable that is surface mounted, providing it is out of reach and cannot be damaged. No different from t&e.

Obviously if it is buried then yes, but to be honest, i would do everything i can to avoid an RCD on the front end of it, even if it meant trunking. Its a piece of cake to work with and looks a lot neater.

There is no problem getting the neutrals into a termination point. Just a little care and time taken to do the job.

Why would you need to sleeve a neutral conductor in a cu?

CPC's yes.

 

[spamwize2]

hi cant you run the supplies in hi tuff? i just bought 25mm tails and they were £1 per foot!