Table 310.15(B)(2)(a) & 310.16 '08

[1793]

I will be doing an Outdoor Residential Service Heavyup and I will be adding a few more circuits. My question is in line of derateing. I will have 6 circuits that will be MWBC and one standard for a total of 7 circuits. If I have 3 sets of MWBC the neutral, grounded conductor, for these circuits do not count as a CCC --- correct?

I?m installing #12 THHN/THWN in 3/4? EMT so fill is not an issue just want to be sure I have the ampacity I need for each 20 amp circuit.

 

[C3PO]

If I am understanding you right, in your example you would have 8 ccc so the 12awg would still be ok for 20A

 

[480sparky]

If I am understanding you right, in your example you would have 8 ccc so the 12awg would still be ok for 20A

That's what I was thinking.

Now, what's Heavyup?

 

[C3PO]

Now, what's Heavyup?

My guess was a service upgrade ????

 

[480sparky]

My guess was a service upgrade ????

Why would that affect the ccc count?

 

[C3PO]

Why would that affect the ccc count?

I will be doing an Outdoor Residential Service Heavyup and I will be adding a few more circuits.

He is also adding some circuits

 

[480sparky]

He is also adding some circuits

But what does the service have to do with derating branch circuit conductors? T310.15(b)(2)(a) could care less if it's a 60a single phase 12/240volt or a 4,000amp 3-ph 480volt service.

 

[charlie b]

Why would that affect the ccc count?

It wouldn't. He was just setting the scene, before presenting the question. I agree that you have only 8 CCCs, and that #12 THHN conductors are fine for 20 amp circuits.

 

[1793]

But what does the service have to do with derating branch circuit conductors?

Nothing, just adding information. Most of the time everyone wants more info.

Just like my wife, you ask her" how much more money do you need to feel comfortable?" and she will reply: "a dollar more."

 

[1793]

It wouldn't. He was just setting the scene, ...

Thank you charlie b

 

[480sparky]

Still.... what's Heavyup?

 

[1793]

Still.... what's Heavyup?

Service Uprgrade, you know say from 100 to 200 amps.

 

[480sparky]

Service Uprgrade, you know say from 100 to 200 amps.

Note to self...."Remember that." :smile:

New to me. :wink:

 

[1793]

Note to self...."Remember that." :smile:

New to me. :wink:

Was to me too. I had to ask that same question after reading it on this Forum.

 

[480sparky]

Was to me too. I had to ask that same question after reading it on this Forum.

Once you mentioned your wife and money, I thought it was something you did to her purse..... make it 'heavyup' with spending cash.....

 

[SEO]

I think service up-grade sounds a little more professional.:smile: