SWA cable rating - 2 core or 3 core?

[teacherspark]

Hi guys and girls,

When calculating current carrying capacity of SWA; if you have 3 core swa but one core is being used as the cpc, is the SWA classed as 2 core?


Many Thanks

 

[multimick]

Hi guys and girls,

When calculating current carrying capacity of SWA; if you have 3 core swa but one core is being used as the cpc, is the SWA classed as 2 core?


Many Thanks

no

 

[Pete999]

No

 

[teacherspark]

no

Thanks for your reply multimick.

So 3 core: phase L1, phase L2 and neutral with separate cpc can carry same current as 3 core: Phase, neutral and cpc?

They both get as warm as each other?

I appreciate the time you took to write your answer.

Many thanks

 

[multimick]

Thanks for your reply multimick.

So 3 core: phase L1, phase L2 and neutral with separate cpc can carry same current as 3 core: Phase, neutral and cpc?

They both get as warm as each other?

I appreciate the time you took to write your answer.

Many thanks

Yes, that took a long time as well

 

[HandySparks]

When calculating current carrying capacity of SWA; if you have 3 core swa but one core is being used as the cpc, is the SWA classed as 2 core?

If you use 3 core SWA for a single phase circuit, it won't dissipate as much heat as the same cable used for a 3 phase circuit running at the same current. I use the 'single phase' column values in the current carrying capacity tables.

 

[westward10]

I tend to judge it on the number of cores and not their function as more cores are likely to prevent heat dissipation. Some feel the third core used as a cpc is negligible.

 

[westward10]

I just love helpful responses.

 

[multimick]

i agree but he original question was about CCC.

 

[westward10]

i agree but he original question was about CCC.

.??

 

[HandySparks]

I tend to judge it on the number of cores and not their function as more cores are likely to prevent heat dissipation. Some feel the third core used as a cpc is negligible.

If an extra core carrying no/negligible current made a significant difference to the heat dissipation, then there would be separate columns for 3 phase 3 core and 3 phase 4 core.

 

[multimick]

sorry west i wrote it before your post

 

[teacherspark]

More warm cores (more phases) would slow heat dissipation. A cold core would increase the rate of heat loss.

Heat would be transferred from phase to colder cpc and out 'the other side', dissipating it quicker. If all the cores were warm to begin in with you wouldn't get heat transfer as they are all warm.

I guess this is why I'm here discussing it.

 

[westward10]

If an extra core carrying no/negligible current made a significant difference to the heat dissipation, then there would be separate columns for 3 phase 3 core and 3 phase 4 core.

Possibly but it is interesting that YY, CY and SY cables give a ccc for the conductor csa and then you apply correction factors for core quantity with no relevance to core function.

 

[Ian1981]

Possibly but it is interesting that YY, CY and SY cables give a ccc for the conductor csa and then you apply correction factors for core quantity with no relevance to core function.

Yes but they are devil cables designed to confuse numpties like myself