Help: I don't understand how to use Table 1 Ch. 9...

[DavJ09]

I read through Table 1 Ch. 9's information bullets and I'm at a loss as to how to apply the calculations to specific cables/tubings.

Say ENT is being installed in the second floor of three stories (in accordance with 362.10(1)), then how would I use Table 1 Ch. 9?




-- J. Davis (tapatalk!)

 

[Jon456]

Are you referring to: "Chapter 9, Table 1: Percent of Cross Section of Conduit and Tubing for Conductors"?

If so, that is simply the allowable fill ratio based on the number of conductors in the conduit.

 

[DavJ09]

What is a fill ratio?

-- J. Davis (tapatalk!)

 

[augie47]

Again, assuming Table 1 Chapter 9.
In most cases the work has been done for you in the Tables following.
Table 4 (pg 672 in '08) shows the allowable fill such as .181insq for over 2 wires,
You then go to Table 5, pick your wire type, check the area and add for fill.
Even better, if all your wires are the same size, Go to Annex C, Table C2 for your ENT ((Pg 709 in ;08) and the work has been done for you.

 

[DavJ09]

I am referring exactly to your question. And, thank you for your answers.

-- J. Davis (tapatalk!)

 

[Dennis Alwon]

Annex C is only good if the wires in the conduit are the same size.

Go to Table 5 and choose the wire sizes and insulation type and write down the sq.in of those wires.

Add them up and then look in Table 4 for the conduit type and size and see what number in sq.in column (usually 40%- last column) and as long as the wire fill is less than the conduit sq. in then you are good to go.

 

[kwired]

All that table 1 is telling you is that a raceway with a single conductor in it - the conductor can not take up more then 53% of the space inside the raceway.

If the raceway has 2 conductors in it they can not take up more then 31% of the space in the raceway.

If there are more than two conductors they can not take up more then 40% of the space in the raceway.

Other raceway fill tables use this information for the results listed in those tables, but if you are calculating without those tables for some reason, you still have table 1 as the base.

 

[DavJ09]

Thank you!

I'm finding there are so many technicalities I've done yet haven't actually acknowledged... I'm stoked to be working with electricity again. I hope I land the job I've put so much effort towards!

Thank you, everyone!

-- J. Davis (tapatalk!)