Swa/pvc cable size

[weepaul]

Does anyone know the cable size for a 400V 4C SWA/PVC Cable run on galvanised tray for a 250A supply. Is it a 4C 150mm with a 70mm CPC?????


Thanks in advance

 

[ian.settle1]

Is it's own on the tray or in a group of cables, ambient temp, length of run to name a few things needed to even confirm what you are asking as volt drop also needs to be taken into account.

 

[weepaul]

Yes Ian.settle1 its on its own on the tray its an 80M run and the ambient temp i believe is 30 is that enough info?

 

[Deleted member 26818]

Table 4D4A Multicore 70ºC armoured thermoplastic insulated cables.
Reference method E (in free air or on a perforated cable tray etc, horizontal or vertical).
95mm² cable has a current carrying capacity of 251A. Impedance per meter of 0.43mV.
120mm² cable has a current carrying capacity of 290A. Impedance per meter of 0.35mV.
150mm² cable has a current carrying capacity of 332A. Impedance per meter of 0.29mV.

 

[weepaul]

Table 4D4A Multicore 70ºC armoured thermoplastic insulated cables.
Reference method E (in free air or on a perforated cable tray etc, horizontal or vertical).
95mm² cable has a current carrying capacity of 251A. Impedance per meter of 0.43mV.
120mm² cable has a current carrying capacity of 290A. Impedance per meter of 0.35mV.
150mm² cable has a current carrying capacity of 332A. Impedance per meter of 0.29mV.

Thanks for the reply & help

 

[Engineer54]

Weepaul,

No need for the stated 70mm cpc, on the 4 core cable sizes, that Spin gave you. All have armouring CSA in excess of minimum cpc requirments.

Minimum CSA of SWA to meet 54G

95mm min CSA 107.2mm ...CSA of armour 160mm
120mm min CSA 135.3mm ...CSA of armour 220mm
150mm min CSA 169.2mm ...CSA of armour 240mm

That's a few more bob saved for you!! haha!!!

 

[Sintra]

So long as it is PVC SWA PVC those figures are fine but if it is XLPE SWA PVC then only the 120mm 4 core is suitable with armour being used as cpc 206mm steel which has a copper equivilant of 66.2mm.


Sent from my iPhone using Tapatalk.

 

[Engineer54]

So long as it is PVC SWA PVC those figures are fine but if it is XLPE SWA PVC then only the 120mm 4 core is suitable with armour being used as cpc 206mm steel which has a copper equivilant of 66.2mm.


Sent from my iPhone using Tapatalk.

I think you'll find that any SWA cable with 4 cores, of thermosetting or thermoplastic will meet cpc minimal requirements upto around 240/300mm. It's when you come down to 2 or 3 cores, that you really have to check with the manufacturers data sheets to ensure compliance...

 

[Sintra]

Not according to this table.


http://www.earthingnuts.co.uk/pdf/pvc_xlpe.pdf

Sent from my iPhone using Tapatalk.

 

[Engineer54]

Haha!!, ....but it does for this table, Which i've been using now for a number of years. (Figures in brackets fail minimal CSA requirements) ...But there is typo errors in there...lol!!!


Sorry .... can't get the table to pan out correctly!!!!

 

[Deleted member 26818]

700ºC nice.
I couldn't make head nor tail of that table.
I use one produced by a friend from the IEE.
That lists 95mm² 90ºC 4 core as having a CSA of 147mm².
As an aside, there is no way that 206mm² steel has a copper equivelance of 66.2m², more in the region of 26mm².

 

[ian.settle1]

700ºC nice.
I couldn't make head nor tail of that table.
I use one produced by a friend from the IEE.
That lists 95mm² 90ºC 4 core as having a CSA of 147mm².
As an aside, there is no way that 206mm² steel has a copper equivelance of 66.2m², more in the region of 26mm².

Thats some temp it can handle

 

[johnboy6083]

can anybody give us a definitave way of converting steel CSA into equivelant copper?

Thanks,

John

 

[Engineer54]

700ºC nice.
I couldn't make head nor tail of that table.
I use one produced by a friend from the IEE.
That lists 95mm² 90ºC 4 core as having a CSA of 147mm².
As an aside, there is no way that 206mm² steel has a copper equivelance of 66.2m², more in the region of 26mm².

Spin,

Are you talking about the table produced by John Peckham (i think that's his name)?? If so that is the table i'm refering to in my above post. I've always found it to be spot on, apart from a couple of typo errors....

 

[Chr!s]

As an aside, there is no way that 206mm² steel has a copper equivelance of 66.2m², more in the region of 26mm².

About right to my calcs spin

can anybody give us a definitave way of converting steel CSA into equivelant copper?

its approximately 8 -1

 

[Deleted member 26818]

Here's one way:
Electrical Conductivity of Materials - Resources - Blue Sea Systems
Although it's not very exact as the conductance of steel is indicted as being between 3 to 15. With copper as usual being 100.
I use the 8:1 ratio.
Yes, John Peckham he's the chap.
Of course this is all a bit rule of thumb.
The only way to really determine the equivalance would be to physically measure the actual materials being compared.

 

[Engineer54]

Spin,

Well, for the best part of my years i ''Always'' used to go by calculation, but now basically use this guy's table as a good rule of thumb. When cable lengths start getting long, i will still calculate, just to be on the safe side, especially where compliance is just scraping through.

 

[Deleted member 26818]

Same here.

 

[Chr!s]

I use the 8:1 ratio.
Yes, John Peckham he's the chap.
Of course this is all a bit rule of thumb.
The only way to really determine the equivalance would be to physically measure the actual materials being compared.

Spin, you only want to use this where bonding applies though

 

[Deleted member 26818]

Spin, you only want to use this where bonding applies though

CPC and bonding, except where PME conditions apply.