Because of derating factor the wire ampacity is less than 18 amps, is that ok to put that wire in 20 amps braker..

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- Thread starter Rufino
- Start date

Because of derating factor the wire ampacity is less than 18 amps, is that ok to put that wire in 20 amps braker..

- Location
- New Jersey

- Occupation
- Electrician

- Location
- Chapel Hill, NC

- Occupation
- Retired Electrical Contractor

16 #12== 16 x 2.25 = 36

17 #10 = 17 * 2.5 = 42.5

42.5 + 36 = 78.5 so you should be good.

17 # 10 = .0211==.3631 in^2

1 1/4"

- Location
- New Jersey

- Occupation
- Journeyman Electrician

How did you come up with less than 18 amps after derating? Also what kind of raceway, for 1" EMT your tubing is too small.

Because of derating factor the wire ampacity is less than 18 amps, is that ok to put that wire in 20 amps braker..

- Location
- Chapel Hill, NC

- Occupation
- Retired Electrical Contractor

It would be okay to put on a 20 if the load was equal to or less than 18 amps but the fact is the de-rating would be 20 amps as Gus stated.

Because of derating factor the wire ampacity is less than 18 amps, is that ok to put that wire in 20 amps braker..

#10 at 90C is 40 amps. 50% of 40 amps is 20 amps

If you the math thats correct .. but is that what nec permit... because when you look at the boxes fill in the nec you have to use less than the actual cubic inches(a) simply do the math 8x8x4 = 256 cu in good for 100+ #10s

Your derating for 16 current-carry #10 THWN-2 should be 20 amps I believe

Thanks

16 #12== 16 x 2.25 = 36

17 #10 = 17 * 2.5 = 42.5

42.5 + 36 = 78.5 so you should be good.

17 # 10 = .0211==.3631 in^2

1 1/4"

- Location
- New Jersey

- Occupation
- Journeyman Electrician

Where does it say that?If you the math thats correct .. but is that what nec permit... because when you look at the boxes fill in the nec you have to use less than the actual cubic inches

- Location
- Chapel Hill, NC

- Occupation
- Retired Electrical Contractor

I started to mention that earlier but I realized it didn't matter in this case. Yes the dimensions in the table is interior dimension

Should be 20 amp 50% derating..How did you come up with less than 18 amps after derating? Also what kind of raceway, for 1" EMT your tubing is too small.

- Location
- New Jersey

- Occupation
- Journeyman Electrician

Got it, what type of raceway?Should be 20 amp 50% derating..

Table 314.16 AWhere does it say that?