Armouring for earth

[tigerpaul]

Hello Fellas,

I think I might have dropped a ------- (never a good feeling)
All my SWA cables turned up for a job I'm about to start.
I've got 10mm 2 cores and 4 cores, for SP&N and TP&N DB's
Also 16mm 2 cores and 4 cores, for SP&N and TP%N DB's

Now I'm thinking about whether the armouring will suffice for the earth. I have no information on the design of the job so I'm unaware of any Ze or pfc values.

I know I can always strap a G&Y cpc to the cable later but it looks untidy and I'll have to go back to the gaffer saying I miscalculated on cable (and look like a muppet)

I know I should have got 3 and 5 cores in the first place!

 

[tigerpaul]

Okay I've just found the "sticky" on this subject, and am reading hoping for the best.

Would still appreciate anyones comments though...

 

[Welchyboy]

there is a guide on here i have seen before about values of SWA sheath as a cpc that i stuck in my regs book, and im pretty sure as long as your using PVC/SWA/PVC and not XLPE cable your fine until you start getting into the big boy sizes of around 95mm+

 

[micknew]

Agree with Welchyboy.
We always calculate swa sizes with Amtech software and have never had a failure flagged up for the armour as cpc. We specialise in industrial works in foundry's etc so have done hundreds of calcs for swa's.

 

[Richard Burns]

These are the values I have for the armour copper equivalent csa for
10mm2
2 core PVC 17.7mm2
4 core PVC 20.3mm2
2 core XLPE 8.36 mm2
4 core XLPE 13.5mm2
16mm2
2 core PVC 20.3mm2
4 core PVC 31.9mm2
2 core XLPE 13.5mm2
4 core XLPE 16.0mm2

But might be best to check the cable manufacturers information.

 

[tigerpaul]

Thanks chaps,

It is XLPE cable we're using, only short runs indoors. I'm going to try and get manufacturers details tomorrow and hopefully I'll be alright.

 

[BruceB]

There is a table on the earthingnuts website:
http://www.earthingnuts.co.uk/pdf/pvc_xlpe.pdf

 

[Darkwood]

Shouldnt be a problem at those small sizes but XPLE would need confirming i always use pvc also freindly word of caution Tiger! Watch your P's and Q's its a public forum and the Mods dont appreciate swearing on any level as it lowers the value of the site :38:

 

[Engineer54]

Here you go, The figure in brackets are those cable that DON'T comply!! As you can see your fine all the way up to 95mm, on 2 core SWA cables...



Table for 90[SUP]0[/SUP]C Thermosetting SWA cables operating at 70[SUP]0[/SUP]C.

Conductor CSA​	Minimum CSA of SWA to meet 54G​	CSA of armour 2 core​	CSA of armour 3 core​	CSA of armour 4 core ​
1.5​	3.4​	16​	17​	18​
2.5​	5.7​	17​	19​	20​
4​	9.0​	19​	21​	23​
6​	13.6​	22​	23​	36​
10​	22.6​	26​	39​	43​
16​	36.1​	41​	44​	49​
25​	36.1​	42​	62​	70​
35​	36.1​	62​	70​	80​
50​	56.4​	68​	78​	90​
70​	79.0​	80​	90​	131​
95​	107.2​	113​	128​	147​
120​	135.3​	(125) ​	141​	206​
150​	169.2​	(138​	201​	230​
185​	208.6​	(191) ​	220​	255​
240​	270.6​	(215) ​	(250)​	289​
300​	338.3​	(235) ​	(269)​	(319)​
400​	451.0​	(265) ​	(304)​	(452)​

 

[tigerpaul]

Thanks chaps, gonna get on the case today.

 

[tigerpaul]

Looks like PVC cables would have been okay but as were using XLPE they are not... Typical!
Hopefully if I get moe info then the adiabatic equation might get me out of a hole..

 

[Engineer54]

Looks like PVC cables would have been okay but as were using XLPE they are not... Typical!
Hopefully if I get moe info then the adiabatic equation might get me out of a hole..

I've got 10mm 2 cores and 4 cores, for SP&N and TP&N DB's
Also 16mm 2 cores and 4 cores, for SP&N and TP%N DB's

What are you talking about?? Look at the table i posted again!!. ....The cables you mentioned above ALL conform with the minimal CSA required for your CPC!!!

 

[Amp David]

Happy days!!:1eye:

Do they still manufacture PVC SWA?