hhsting
Senior Member
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- Glen bunie, md, us
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- Junior plan reviewer
I looked in NEC 2017 Section 240 but did not find this. Is their anything in NEC 2017 that says there are 80% breaker and 100% rated breakers?
80% rated and 100% rated breakers
- Thread starter hhsting
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- Bremerton, Washington
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- Master Electrician
Yes. 110. 3 B
synchro
Senior Member
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- Chicago, IL
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- EE
Also see 210.20(A) and its exception.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
See 210.19(A)(1), 210.20(A), 215.2(A)(1), 215.3, 230.42,
kwired
Electron manager
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- NE Nebraska
Notice majority of what is addressed by NEC involves selecting minimum conductor ampacity.
I was taught one the major reasons for this is a standard device depends on sinking heat into the terminations therefore you need to take the continuous load at 125% when determining minimum ampacity. A 100% device doesn't depend on terminations for heat sinking (which especially makes sense if the OCPD is electronic instead of thermal) and therefore doesn't need to increase conductor size for the sake of termination temperature.
I was taught one the major reasons for this is a standard device depends on sinking heat into the terminations therefore you need to take the continuous load at 125% when determining minimum ampacity. A 100% device doesn't depend on terminations for heat sinking (which especially makes sense if the OCPD is electronic instead of thermal) and therefore doesn't need to increase conductor size for the sake of termination temperature.
Tulsa Electrician
Senior Member
- Location
- Tulsa
- Occupation
- Electrician
Since he did not mention branch circuit or feeder etc.
With the lack of info I would go with first answer of 110. 3 (B) as well.
Depending on type of installation. 240.91 (B)
Then 240.91 (B) (2) takes you to the mentioned 110.3 (B) ( 2014 NEC) " All equipment in which the Conductors terminate is listed and marked for the application"
Note: Please do not skip past 240.91 (B) (1)
With the lack of info I would go with first answer of 110. 3 (B) as well.
Depending on type of installation. 240.91 (B)
Then 240.91 (B) (2) takes you to the mentioned 110.3 (B) ( 2014 NEC) " All equipment in which the Conductors terminate is listed and marked for the application"
Note: Please do not skip past 240.91 (B) (1)
hhsting
Senior Member
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- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have one for feeder and one for branch circuit. For both types of install
winnie
Senior Member
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- Springfield, MA, USA
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- Electric motor research
Going from memory here, but I don't believe that 80% breakers are explicitly mentioned at all.
Instead 'standard' breakers are 80% rated, and code is designed for 'standard' breakers.
What you will find are exceptions to the standard requirements for 100% rated breakers.
-Jon
Instead 'standard' breakers are 80% rated, and code is designed for 'standard' breakers.
What you will find are exceptions to the standard requirements for 100% rated breakers.
-Jon
- Status