7,300 Watts supplied on a 2.5mm2 T&E.

whjohnson: 
 

Go on Dave, tell us what current a 2.5mm cable can carry at -273K. I'm intrigued.

Since 2.5mm at 70' will carry something like 21A in a best case clipped direct scenario, and given that -273K is absolute zero in degrees C terms, I would imagine that the current carrying capacity would be much much higher. However, we would need length of run and duration of load to get a bit nearer.

very very roughly, with ambient temp 30 degrees, with a 32 A load after a few minutes use (up to 5 mins but may be less):

• Ref method C (clipped direct) get to about 80 deg C
• Ref method 102# gets to about 90 deg C
• Ref method 103# gets to well over 100 degrees C

I think in this particular case, the installation may have been lucky based on duration of use and ambient temperature, and I'd guess Ref method C ???

If for any reason the cable is accidentally further thermally insulated, or the ambient temp gets above 25 degrees, things could change quite quickly.

whjohnson: 
 

Go on Dave, tell us what current a 2.5mm cable can carry at -273K. I'm intrigued.

Since 2.5mm at 70' will carry something like 21A in a best case clipped direct scenario, and given that -273K is absolute zero in degrees C terms, I would imagine that the current carrying capacity would be much much higher. However, we would need length of run and duration of load to get a bit nearer.

very very roughly, with ambient temp 30 degrees, with a 32 A load after a few minutes use (up to 5 mins but may be less):

• Ref method C (clipped direct) get to about 80 deg C
• Ref method 102# gets to about 90 deg C
• Ref method 103# gets to well over 100 degrees C

I think in this particular case, the installation may have been lucky based on duration of use and ambient temperature, and I'd guess Ref method C ???

If for any reason the cable is accidentally further thermally insulated, or the ambient temp gets above 25 degrees, things could change quite quickly.