Sizing multi - conductor cable

[ZMIKE123]

IF i have a 3/c#12 cable for example :

1. what is the the diam. and area of the 3 individual conductors ?
2. what is the total diam. and area of the cable including insulation ?

 

[skeshesh]

IF i have a 3/c#12 cable for example :

1. what is the the diam. and area of the 3 individual conductors ?
2. what is the total diam. and area of the cable including insulation ?

1. NEC tables
2. Consult Mfg. documents

 

[ZMIKE123]

Thank you for your answers

Thank you for your answers

1. NEC tables
2. Consult Mfg. documents

thank you for your help
i know im just learning so please bear with me
i am a new electrical draftsman learning design now
i know about some of the tables in the NEC also
here is an example i am confused about

3/C #12 AWG = 0.167 sq. in.x 10 cables = 1.67 sq. in.

this example is from a book i have on electrical design
my question please explain how how he got the area to be .167 sq. in.

here is my calculation:
i found the diameter # 12 wire from the tables to = .081 inches
i divide that by 2 to get the radius = .0405
area = 3.14 x radius squared = 3.14 x .0016 = .0050 sq. inches

.0050 sq inches does not equal to .167 sq inches
this is where i am confused

thank you

 

[Dennis Alwon]

Speaking of #12 makes no sense unless you know what kind of insulation is on the wire. If you have a multiwire cable with 3- 12 wires then you need to know the insulation on the wire.

You can get the wire and measure it and then do the math or go to the website of the distributor and look up the area.

For instance a #12 bare copper wire =.005 sq. in. while a #12 with TW insulation has an area of .0181 sq. in. A #12 with THHN insulation has .0133 sq. inches.

You can't just figure the size of each wire and determine the cable size.

 

[BJ Conner]

There are a couple of diameters here,

There are a couple of diameters here,

This is a cut sheet from Okonite. There is the diameter of the indiviual conductors ( bare wire and insulation ) and the overall diameter of the cable.
For this cable 3C/12 has an OD of 0.44". and an area of 0.16 In-sq.

http://www.okonite.com/Product_Catalog/section4/sec4-pdf/4-7.pdf

 

[Dennis Alwon]

Here is Southwire's wire

 

[ZMIKE123]

THANK YOU EVERYBODY FOR ALL YOUR HELP (multi cunductor sizing )

THANK YOU EVERYBODY FOR ALL YOUR HELP (multi cunductor sizing )

thank you for your help
i know im just learning so please bear with me
i am a new electrical draftsman learning design now
i know about some of the tables in the NEC also
here is an example i am confused about

3/C #12 AWG = 0.167 sq. in.x 10 cables = 1.67 sq. in.

this example is from a book i have on electrical design
my question please explain how how he got the area to be .167 sq. in.

here is my calculation:
i found the diameter # 12 wire from the tables to = .081 inches
i divide that by 2 to get the radius = .0405
area = 3.14 x radius squared = 3.14 x .0016 = .0050 sq. inches

.0050 sq inches does not equal to .167 sq inches
this is where i am confused

thank you

THANK YOU EVERYONE FOR ALL YOUR HELP
they did not explain this at all in this book
they left this all out
manufacturers sizes /different insulation / etc.............
i thought it was a standard size and that was it

 

[LarryFine]

Mike, welcome to the forum!

When installing a cable in conduit, the individual conductors don't matter. You use the cable's outer diameter (or major diameter if oval).