SY Cable - current carrying capacity

[yellowvanman]

Anyone know which table in the BGB can be used for SY current ratings or can direct me to a relevant table?

 

[Guest123]

I have a PDF somewhere for SY cable as the CCC differs slightly from that of the book.

I'll look for it now.

 

[Guest123]

Here she be.

 

[yellowvanman]

Dilemma I have.

5 core SY cable - 3 phase circuit (neutral not used) would the de-rating factor apply, as obviously only 3 cores are carrying current!

In my case I've got 4mm/5c handy and the machine is rated at 34A.

 

[Guest123]

I would say treat as 3c and no factor to apply.

 

[Darkwood]

Id treat it as its core no' (5), the rating of the cable isnt so simple to work out if the core is their but not used it still ocuppies space altering the effective surface area the other conductors have against the outer-sheath, id get 6mm but be careful here although Elland cables supply a good proportion of the cable near me as its just down the road other manufacturers exist and may differ as they have variations with regards to braiding and sheathing thickness.
And to note the 4mm 5core is rated at 34amps and subject to manu' spec derating of 0.75, a 6mm will only leave you with a 33amp rating without other factors taken into account so loading characteristics of machine might be needed to be taken into account but if running at 34 amps then 10mm may be your choice.

 

[Guest123]

I understand what you say but, at worst it would be 4 core still with no factor to apply as the CPC is never included, ie, 2 core for SP & 4 core for TP as per BS 7671.

 

[Darkwood]

I understand what you say but, at worst it would be 4 core still with no factor to apply as the CPC is never included, ie, 2 core for SP & 4 core for TP as per BS 7671.

Good point made but although i have every confidence in you id be inclined to check with manufacturer with this one but know what your saying, im used to saying 5core when i get 4core and earth and ive always got the core im after.

 

[red1]

HI mr guest 123 could you please send me a link to SY CCC table.

Many thanx