Doing my first sub-main in SWA.

[DYCHE4230]

Switch fuse at the meter end then
Use 25mm 2 core swa & a seperate 16mm mec.
.

Easyfox Would the 16mm MEC need protecting? Cheers

 

[sparkyork]

is it not permissable to run it in plastic trunking then?

 

[jibspark]

arnt 3-4 meter tails too long? i thought there was a limit on length but i cant remember what.....

 

[Mike P]

Mechanical protection not needed on any thing over 4mm.

I refer of course to the MEC

 

[Jurassic Spark]

Why are you using 25mm SWA? 16mm SWA is adequate for 100amp supply - use 3-core with one core used as earth to supplement the armouring.

 

[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.