Stranded VS Solid

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Stranded VS Solid


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jim dungar

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Staff member
Location
Wisconsin
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PE (Retired) - Power Systems
# Also, skin effect is another great advantage of using stranded.

As far as skin effect goes, individual stranding does not provide sufficient separation and the conductor is treated as if it were a solid. This is also true for compact and sectored construction as well.

For normal power systems of 60Hz, skin effect is a fairly useless topic to be taught.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
As far as skin effect goes, individual stranding does not provide sufficient separation and the conductor is treated as if it were a solid. This is also true for compact and sectored construction as well.

For normal power systems of 60Hz, skin effect is a fairly useless topic to be taught.

I think skin effect should indeed be taught. That way it would be understood why, at 60 Hz, we don't bother with adjusting for skin effect given the size of the conductors we use.
 

jim dungar

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Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I think skin effect should indeed be taught. That way it would be understood why, at 60 Hz, we don't bother with adjusting for skin effect given the size of the conductors we use.
I think in general it is simply a 'fun fact' which is almost always used out of context. After all, when skin effect does become an issue so might proximity effect, but we almost never hear of this topic even being taught.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I'll bite: What is proximity effect?
In a nutshell, the closer a group of alternating current carrying conductors are to each other, the greater the effect the magnetism created by one conductor will be on the current in the other conductors.

Wikipedia has an entry here.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
For raceways filled to near capacity stranded is the only way to go. With this new trend towards value engineering we constantly see 1" EMT's spec'd with 15-#10 solid conductors as the norm. There is no way on earth that 15 solid #10 conductors is as easy to pull in as 15 stranded #10 conductors.

Frankly, I don't think I'd even try it.

Unfortunately I've had to do it, and often. For some reason engineers love to spec only solid conductors and they also like to load conduits to their maximum fill. Can someone say pulling machine. :roll:
 

jim dungar

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Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Proximity effect: when conductors are lying next to each (i.e. in conduit) the magnetic forces cause more current to flow in one half of the conductor than in the other.​

From General Cable:
The proximity effect also increases the effective resistance and is associated with the magnetic fields of two conductors which are close together. If each carries a current in the same direction, the halves of the conductors in close proximity are cut by more magnetic flux than the remote halves. Consequently the current distribution is not even throughout the cross-section, a greater proportion being carried by the remote halves. If the currents are in opposite directions, the halves in close proximity will carry the greater density of current.

cut and paste link
www.generalcable.co.nz/Technical/10.3.2.1.pdf
 
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stjohnbarleycorn

Senior Member
on the original question, you might take into effect that you can't use stranded on the standard grade receptacles, I have heard about twisting counterclockwise, but unless you use a better grade you need to go with solid. Although someone may prove me wrong.
 

LEO2854

Esteemed Member
Location
Ma
on the original question, you might take into effect that you can't use stranded on the standard grade receptacles, I have heard about twisting counterclockwise, but unless you use a better grade you need to go with solid. Although someone may prove me wrong.

Just use stake on's
 
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