Current Oven Wire

[JohnW2]

Googling says 7/0.036 = 4.6mm².

... and my calculator says that 7/0.036" = 4.59685mm² - so it sounds as if Mr Google got it right! However, as I've been asking, does anyone know what its CCC (or that of 7/029) was regarded as?

Kind Regards, John

 

[EFLImpudence]

Does anyone know what the stated CCCs of those cables were, and what OPDs those CCCs related to?

Does it matter?

If they are equal to 2.5mm² and 4.6mm² respectively (which they are), can we not equate them to todays CCCs?

 

[JohnW2]

Does anyone know what the stated CCCs of those cables were, and what OPDs those CCCs related to?

Does it matter? If they are equal to 2.5mm² and 4.6mm² respectively (which they are), can we not equate them to todays CCCs?

Whilst, as I've said, I agree that 7/036 = 4.6mm², my calculator says that 7/029 = 2.98mm², not 2.5mm² - and I don't know what "today's CCCs" would be for either 3.0 or 4.6 mm².

That aside, in the context in which this issue arose, it probably "matters" only if the CCCs used in those days differ (at least, pro rata) from those we use today - since, if they were different, we need to know what they then regarded as the CCCs in order to determine whether that might have been part of the reason for favouring ring finals over radials supplying the same current.

Kind Regards, John

 

[EFLImpudence]

I have found this:

http://www.electrical-contractor.net/PC/ASEE_T13.jpg

I can only assume they relate to 3036s, in which case I may have been right all along.

 

[JohnW2]

I have found this:
http://www.electrical-contractor.net/PC/ASEE_T13.jpg
I can only assume they relate to 3036s, in which case I may have been right all along.

Assuming that they do relate to 3036's these 'in free air' CCC figures seem rather pessimistic in terms of our 'modern ' figures. For 7/036 (aka 4.6mm²), 28A on a 3036 would translate to 38.6A in modern tables, whereas those modern tables give a CCC of 40A 'in free air' for 4mm², let alone 4.6mm². For 7/029 (aka 3.0²), 20A on a 3036 would translate to 27.6A in modern tables, whereas those modern tables give a CCC of 30A 'in free air' for 2.5mm², let alone 3.0mm².

Kind Regards, John