Ampacity question.

[Cuddy613]

The question im having trouble with is..

What is the permissible ampacity for six #8 Copper T-90 Nylon Conductors in Conduit?

Can anyone help me out and let me know how to figure this out?


Thanks

 

[augie47]

With students, we have found the best help is to allow you to answer the questions telling how you derived your answer and then we will help...

 

[Cuddy613]

Hey thanks for the quick reply

my problem is i just have no idea how to even go about finding the answer.

 

[suemarkp]

Lookup the ampacity of T90 in table 310.16 (don't know what T90 is, but sounds like THHN). I would use the 90C column at this point.

For the rest, we have to start making assumptions. If we assume all the conductors in the raceway are current carrying, you have to derate the ampacity above by the 80% factor for 4-6 current carrying conductors.

I don't think there are other relevant factors (like ambient temperature), since nothing else was stated.

 

[augie47]

Mark has directed you.
95% of "ampacity" questions will be based on Table 310.16.
Look there and the associated rules in 310.15.
Let us know what that tells you.

 

[jumper]

Is this a NEC or a CEC question?

http://www.southwire.com/ProductCatalog/proddetail.jsp?htmlpreview=true&token=195&desc=T90

Seems to be a Canadian conductor.

 

[rexowner]

All the info you need is in Tables 2 and 5 in the Tables section of the
CEC. Make sure you read the notes to the tables.

Also, if you have an Android phone, there is an app called "CEC Ampacity"
that can help you make the calcs per the CEC.

 

[Cuddy613]

Hey thanks to everyone for their input. Also i forgot to mention that it was indeed at CEC question.

I think i may have figured it out...

I went to table 2 and found that allowable ampacity for No. 8 T90 was 45amps. But because I have 6 of them I go to table 5c and multiply 45amps by a correction factor of .70 to come up with 31.5 amps.

Would someone be able to confirm if this is correct?

Thanks for all of your help

 

[infinity]

Hey thanks to everyone for their input. Also i forgot to mention that it was indeed at CEC question.

I think i may have figured it out...

I went to table 2 and found that allowable ampacity for No. 8 T90 was 45amps. But because I have 6 of them I go to table 5c and multiply 45amps by a correction factor of .70 to come up with 31.5 amps.

Would someone be able to confirm if this is correct?

Thanks for all of your help

Are the CEC and the NEC tables the same? If so then your calculation is incorrect.