# Cec code rules



## Donniep1234 (11 mo ago)

What is the raw ampacity of a 250kcmil aluminum single TW conductor in free air?


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## joe-nwt (Mar 28, 2019)

When is the homework due?


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## backstay (Feb 3, 2011)

NEC is 265, doesn’t help you though.


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## emtnut (Mar 1, 2015)

Donniep1234 said:


> What is the raw ampacity of a 250kcmil aluminum single TW conductor in free air?


I'll narrow it down for you.
It's either in Table 1,2,3, or 4.

Donnie, it's best if you post CEC questions in the Canadian Electrical Section.
Some of the Canucks here only check that section.


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## Donniep1234 (11 mo ago)

emtnut said:


> I'll narrow it down for you.
> It's either in Table 1,2,3, or 4.
> 
> Donnie, it's best if you post CEC questions in the Canadian Electrical Section.
> Some of the Canucks here only check that section.


Okay I will do that thankyou all for the assistance just have a few questions I was having trouble with For schooling for my apprenticeship


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## SWDweller (Dec 9, 2020)

Other than a class problem no one would use TW in free air. 
First off you have the strain problem to solve. Next there are much better insulators out there for free air. Look at the tri and quadplex wire for instance.


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## wcord (Jan 23, 2011)

The op's question is not related to overhead conductors.
It's to get the student to investigate allowable ampacities by determining the type of wire and the type of installation.
Im going to throw the op a bone.
Look at the question and read the info you have.
1. Insulation type
2. Installation 

You have to cross reference both to get your answer.
Heres your hint. There are 2 tables you have to look up.


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## Donniep1234 (11 mo ago)

wcord said:


> The op's question is not related to overhead conductors.
> It's to get the student to investigate allowable ampacities by determining the type of wire and the type of installation.
> Im going to throw the op a bone.
> Look at the question and read the info you have.
> ...


Thankyou so much


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## Donniep1234 (11 mo ago)

Donniep1234 said:


> Thankyou so much


I came up with 355 amps


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## emtnut (Mar 1, 2015)

Donniep1234 said:


> I came up with 355 amps


How did you get that ??


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## Donniep1234 (11 mo ago)

emtnut said:


> How did you get that ??


I accidentally was looking at the table for copper in free air instead of AL, I went to table 19 and found that “TW” type is rated for 60 degrees. I now have an amperage of 265 amps from table 3


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## wcord (Jan 23, 2011)

Glad you figured out the answer on your own.
You'll find that we'll help point you in the right direction but won't give you the answer.
It takes awhile to learn how to read the code book, and don't expect to memorize it.


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## Donniep1234 (11 mo ago)

wcord said:


> Glad you figured out the answer on your own.
> You'll find that we'll help point you in the right direction but won't give you the answer.
> It takes awhile to learn how to read the code book, and don't expect to memorize it.


I appreciate and respect that thankyou for taking the time to help me out it means a lot!


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