Matt Mckenzie
Member
- Location
- United States
800 amps or less next we use next standard size ocp.... 800 amps or more we use next standard size down ocp? correct?
No.800 amps or less next we use next standard size ocp.... 800 amps or more we use next standard size down ocp? correct?
800 amps or less next we use next standard size ocp.... 800 amps or more we use next standard size down ocp? correct?
Ah, that makes more sense.almost... devices over 800 the conductor ampacity must be equal or greater
(the way u stated it "800" was is both categories)
But there's also 240.91(B) that allows a conductor ampacity of 95% of the ocpd for Devices Rated over 800 Amps for Supervised Industrials. This is the one that allows (4) 500 kCMs (1520A ampacity) to be protected by a 1600-A trip breaker.
VIII. Supervised Industrial Installations
240.90 General. Overcurrent protection in areas of supervised
industrial installations shall comply with all of the
other applicable provisions of this article, except as provided
in Part VIII. The provisions of Part VIII shall be
permitted only to apply to those portions of the electrical
system in the supervised industrial installation used exclusively
for manufacturing or process control activities.
Hey, watch it!... I will also add that IMO 'supervised' means qualified engineering spervision not just a 'Shift supervisor Vinnie'.
I think it's new for 2011.That section is new for 2014 and seeing as you are aware of it I have to assume you know the limitations of it.
I think it's new for 2011.