THHN VS XHHW

John120/240

Senior Member
Location
Olathe, Kansas
My guess is it is the popularity of one product over another. Maybe THHN is considered more

versital than XHHW ? Itruthfully do not know, just a guess. Look at the cost of a 15A recptacle

(three prong) vs a 2 prong ungrounded one. They make a heckuva lot more 3 prong than

2 prong.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
My guess is it is the popularity of one product over another. Maybe THHN is considered more

versital than XHHW ? Itruthfully do not know, just a guess. Look at the cost of a 15A recptacle

(three prong) vs a 2 prong ungrounded one. They make a heckuva lot more 3 prong than

2 prong.
I think the question is why the %age difference is less for a larger size wire
 

eric9822

Senior Member
Location
Camarillo, CA
Occupation
Electrical and Instrumentation Tech
My guess would be that the bulk of the cost is the copper, bigger wire more copper. The amount of copper is the same regardless of the insulation type. I would expect the cost difference in percentage to go down as the wire size increases.
 

steve66

Senior Member
My guess would be that the bulk of the cost is the copper, bigger wire more copper. The amount of copper is the same regardless of the insulation type. I would expect the cost difference in percentage to go down as the wire size increases.
I think you've hit the nail on the head.

For #12, you probably have more insulation than copper in the wire.

For 500 KCM, there might be 10 times as much copper as insulation.
 

Cow

Senior Member
Location
Eastern Oregon
The cost of the raw material and the volume sold determines the price. So it would appear that people who specify XHHW do not use 3/0, but choose the next higher size. For years I've heard that 3/0 is NOT a readily available size in XHHW.
That's standard 200A wire size, so I highly doubt that.
 
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