1000 kcm
- Thread starter domnic
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- Massachusetts
Some will say 'the skin effect' I disagree with that. IMO it is all about heat.
The fatter the conductor the less surface area there is compared to the area inside to dissipate the heat to the air around it.
Or in other words the strands at the center of the 1000 Kcmil have a much harder time shedding their heat then the strands at the center of a 3/0 do.
The fatter the conductor the less surface area there is compared to the area inside to dissipate the heat to the air around it.
Or in other words the strands at the center of the 1000 Kcmil have a much harder time shedding their heat then the strands at the center of a 3/0 do.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
I believe that at 60Hz and 1000 kcmil, skin effect is just barely starting to show itself.
But in the whole, as iwire says, heat dissipation is the dominant issue.
-Jon
But in the whole, as iwire says, heat dissipation is the dominant issue.
-Jon
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
winnie said:
The skin effect ratio for 1000 kcmil @ 60Hz is only 1.068.
Larger diameter conductors are also subject to "proximity effect", which also results in uneven current distribution (more current in less area) in a conductor.
With the price per pound of copper skyrocketing,it is wise to evaluate conductor size and quantity. Take an 800Amp 3P 480V 500FT feed, for instance. 3 runs of 250MCM - $21K ; 2 runs of 500MCM - $28K (recent example, $6.08 / pound). Cable/Conduit System, the price is probably a wash, but a cable tray system??? Definately warrants a second thought.
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