Stranded wire

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Djelite

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Electrician
Why does the national electrical code required conductors in a conduit to be 8 awg or smaller if pull in conduit?
 
Even mixing small and larger stranded conductors in the same raceway can result in damage to the smaller conductors.
Most of my industrial projects used 120 volt controls for the 480 volt motors and we ran the 14s in with the motor conductors, but the plant specs prohibited that where the motor conductors were 4 AWG and larger. There is the possibility of the 14s ending up on the outside radius of the conductors when pulled around the 90s, and if the 14s can't slide they can break because of the longer length required for the out side path around the 90.
 
Many years ago, when I was green and solar micro-inverters required a Grounding Electrode Conductor (min 8awg) to the roof, I was on a solar crew that forgot to put the stranded green 8awg on the truck. But we had the solid bare copper 8awg that was used to bond the racking and inverters out on the array. The crew lead decided to use the solid bare 8awg and pull it to the roof through the 3/4" EMT along with the 10awg circuit conductors. I found out that day why that code section exists.
 
Joe.B said:
For those of us who haven't had the experience, please share. I think I know what you're eluding too, but I have never experienced it...
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I've pulled insulated 8 solid out when replacing a wet niche light with led low volt. It's the only place it's allowed in the code and it was terrible. Had to replace the brass box too which was interesting.
 
kwired said:
I believe you are talking about the 8AWG equipotential bonding conductor here that possibly required to be solid?
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When using a non-metallic raceway between the forming shell and the J-box an insulated #8 solid or stranded conductor is required to be installed in the raceway with the light cord. I have never seen solid used but that is probably because insulated solid #8 was not a common item at the supply houses since the time non-metallic raceways have be used.

#8 solid THW seemed to be popular in my area during the 60's. It must have been quite a bit cheaper than stranded otherwise not sure why it would be preferable.
 
Joe.B said:
For those of us who haven't had the experience, please share. I think I know what you're eluding too, but I have never experienced it...
Click to expand...
It a nutshell, it was super difficult to pull, and the outer nylon jacket of the THHN #10s was coming out super chaffed up. The worst was pulling the loops tight at the LBs. Took a whole lot more time than a proper pull aside from the possible damage issue. It wasn't so bad that we didn't 'get away with it' and finish the job. (But if there was a failed inspection or a service call after that, I wouldn't know.) I may have asked the crew lead if it was really allowed, and he may have said he didn't know why not, but we definitely didn't do that again either. I came away definitely feeling it was not right, and however many years later I learned of the code section I was like...Yup.
 
letgomywago said:
No curt got it.
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He did say it could be solid or stranded. But this is a specific thing in chapter 6 and not a general rule of chapters 1-4. In general solid conductors larger than 10 AWG are not allowed to be pulled through raceways. I don't even like pulling 14 and 12 solid and seldom ever do anymore, stranded pulls easier.
 
jaggedben said:
It a nutshell, it was super difficult to pull, and the outer nylon jacket of the THHN #10s was coming out super chaffed up. The worst was pulling the loops tight at the LBs. Took a whole lot more time than a proper pull aside from the possible damage issue. It wasn't so bad that we didn't 'get away with it' and finish the job.
Click to expand...
Sometimes damaged insulation problems do not show up until later when the wires in the conduit get wet.
 
kwired said:
He did say it could be solid or stranded. But this is a specific thing in chapter 6 and not a general rule of chapters 1-4. In general solid conductors larger than 10 AWG are not allowed to be pulled through raceways. I don't even like pulling 14 and 12 solid and seldom ever do anymore, stranded pulls easier.
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Oh I prefer solid at that size. It's easier to push and make up clean.
 
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