Does solid carry more voltage than stranded?

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Dennis Alwon

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Wire does not carry voltage...??? :roll:

Assuming you meant current, for practically all NEC applications, there is no difference.
For NEC but doesn't stranded have more surface area and theoretically can carry more current? I have heard this but never thought much about it. I realize the insulation may be the limiting factor.
 

charlie b

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The voltage rating of a conductor is based on the ability of its insulation system to prevent the leakage of current from the metal conductor (stranded or solid, it does not matter) to the outside world (i.e., to the conduit inside which the wire is resting).
 

jim dungar

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For NEC but doesn't stranded have more surface area and theoretically can carry more current? I have heard this but never thought much about it. I realize the insulation may be the limiting factor.

The individual stranding does not increase the effective surface area at 60Hz.
At power line frequencies, including normal harmonics, we are concerned with the cross sectional area of the conductor. Skin effect and proximity effect are negligible below 266kcmil. I recall(?) the skin effect adjustment for 500kcmil is like 1.005, but regardless it is built into the NEC tables.
 

K8MHZ

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For NEC but doesn't stranded have more surface area and theoretically can carry more current? I have heard this but never thought much about it. I realize the insulation may be the limiting factor.

As far as we are concerned, no. The two are made so they are equal. That may mean that solid has more copper than stranded......but.....at 60 hz skin effect (the reason behind the consideration of skin effect) is negligible for the sizes of insulated conductor we are allowed to use solid wire on.

Surface area is a consideration for lightning protection systems because lightning, although technically DC, acts like 100 MHz AC.

You must also consider that 'compact conductors' are squeezed so tight that there is practically no space between the strands and as such, the 'surface area' is practically the same as solid wire.
 

K8MHZ

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The individual stranding does not increase the effective surface area at 60Hz.
At power line frequencies, including normal harmonics, we are concerned with the cross sectional area of the conductor. Skin effect and proximity effect are negligible below 266kcmil. I recall(?) the skin effect adjustment for 500kcmil is like 1.005, but regardless it is built into the NEC tables.

You can see the differences in Table 8 (DC, skin effect not considered) and Table 9 (3 phase AC with skin effect and proximity considered).
 

Dennis Alwon

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You guys are great-- thanks. I knew per NEC it made no difference but was curious if there was an actual difference. :thumbsup:
 

K8MHZ

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You guys are great-- thanks. I knew per NEC it made no difference but was curious if there was an actual difference. :thumbsup:

If you take a look at large antenna feed line, you will notice that it is a hollow tube instead of a solid conductor. This is for the center conductor of the coax. At VHF frequencies, all the current is traveling on or close to the surface so anything in the middle is just a waste of money and adds extra weight.

By large, I mean 2 to 4 inches or more in diameter. The small stuff (LMR 400, for instance) does not use a hollow conductor in the center.
 

Strife

Senior Member
I know you mean AMPs
The problem is not the copper itself.
The problem is temperature limitations on the insulation (check the bare, free air ampacity, it'll blow you away). The copper itself can probably get heated to 200+ celsius and not have a problem.
So the question should be: will a #12 THHN SOLID wire get less or heated past (or bellow) 90degree celsius when fully loaded compared to stranded.
For any practical purpose, I seriously doubt it. I'm sure there's variations, like solid getting 89.5 VS stranded getting 89.8???
Then we're talking terminations. I can see where some terminations are stranded friendly, whereas some are solid friendly. For all it's worth I think most are solid friendly for 15-30A breakers.

If any thing I thought it was the other way around or no difference at all.
 

Eddy Current

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Im going to sound like a real idiot here but i thought everything in Ohms law was carried through the wire. I guess voltage is just a potential?
 

kwired

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Im going to sound like a real idiot here but i thought everything in Ohms law was carried through the wire. I guess voltage is just a potential?

Any conductor can have any voltage applied to it. The insulation is the limiting factor for voltage. Current will create excess heat if conductor is too small.
 
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