# Minimum wire bend radius for 600MCM THHN



## McClary’s Electrical

Tape up a conduit bender shoe and get-r-done...


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## Dennis Alwon

Look at Table 312.6(A) & (B)


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## HARRY304E

Shorty Circuit said:


> Help! Need the minimum allowable bend radius for 600 MCM THHN. The only thing I can find in NEC is 300.31 for wire over 600 volts. This will be at 480. The switchgear manufacturer now claims he's having a problem with bend radius for this wire. He says 500 MCM would be OK but the load feeders are 1200 amps 3 phase so 3 parallel sets of 600 MCM. Over 800 amps the feeders must be rated at full load or above. The enclosure is 40" wide due to space limitations and cannot be wider. 2 SKLA1200s will be mounted vertically. I'm thinking top feeder entry at the rear with a 42 or 48 inch deep enclosure, the last 10" or so will be a wireway for load feeders. They'd come to the bottom, bend forward and back up. The supply is from buswork spliced to adjacent sections. He says 500 MCM would be OK. Would the 10 foot tap rule in 240.21(B)(1) apply inside the enclosure? It could be spliced to 600 MCM just above. One wire manufacturer I contacted says 16 times the wire diameter which is about 0.9 inches or 14.3 inches is the minimum radius. Anyone had experience with this sort of thing? Could these breakers be mounted upside down so that the load lugs are on top or isn't that legal?


 3.1.4 Minimum Bend Radius: Bends in Type THHN shall be made so that the cable will not be damaged.

Look here..:thumbsup:

http://www.southwire.com/support/THHNGuideSpecifications.htm


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## Dennis Alwon

You cannot mount the breaker upside down unless you can comply with 240.81


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## donaldelectrician

Is the Switch Gear American ? 

I have installed EU Switch Gear that is tight as hell on the wire space

, but well made .


Get er done !



Donald "Outstanding Citizen of the Conch Republic "


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## Shorty Circuit

donaldelectrician said:


> Is the Switch Gear American ?
> 
> I have installed EU Switch Gear that is tight as hell on the wire space
> 
> , but well made .
> 
> 
> Get er done !
> 
> 
> 
> Donald "Outstanding Citizen of the Conch Republic "


GE. There will be a ton of room. There will only be two breakers in this section. The GE SKLA1200 breaker is about 15 inches long, 5 inches wide, and 8 inches deep. The enclosure must be deep enough to allow the wire to sweep through 180 degrees from back to front in 36 inches. A 42 inch deep enclosure with the back 6 or 8 inches will be enough. The load feeders will enter from the top at the back, come down past where the wireway will end about 24 inches from the bottom. The Breakers will be at least 24 inches from the bottom and not one on top of the other. The buswork will have to be custom made anyway to match the existing adjacent section. I don't see any problem.


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## Kevlar66

McClary’s Electrical said:


> Tape up a conduit bender shoe and get-r-done...


Lol you got a table for that? Seriously though I’ve been on so many blogs tonight talking about this. I can’t believe there’s no table in the NEC for wire bend radius. I guess F it. Unless the wire breaks or the insulation breaks it’s all good? I’m about to pull 6 runs 1000’ long of 500kcmil. I have to go through 2 j-boxes and we’re being forced to pull from the middle of the run. They don’t want to “splice” the run. So I’m looking for bend radius and sheave ratings. Also funny note I didn’t know it was spelled sheave, everyone calls them shivs like prison and there’s always the jackass jokes. Anyway.


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## paulengr

Dennis Alwon said:


> Look at Table 312.6(A) & (B)


You need to look here.

Two tables. One for a90 requires less space than one for an S curve. The reality is you can come straight in and just make it with an S.

But this is silly. Most breakers that size are made with lugs for 4 350s. That would give you 1200 A without dealing with the 600 MCM and the cable is cheaper and labor costs to install 350 are less than 600.


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## Dennis Alwon

This thread is 11 years old...


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## Dennis Alwon

Kevlar66 said:


> Lol you got a table for that? Seriously though I’ve been on so many blogs tonight talking about this. I can’t believe there’s no table in the NEC for wire bend radius. I guess F it. Unless the wire breaks or the insulation breaks it’s all good? I’m about to pull 6 runs 1000’ long of 500kcmil. I have to go through 2 j-boxes and we’re being forced to pull from the middle of the run. They don’t want to “splice” the run. So I’m looking for bend radius and sheave ratings. Also funny note I didn’t know it was spelled sheave, everyone calls them shivs like prison and there’s always the jackass jokes. Anyway.


312.6(A & B) has the bending radius


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