Mike Dolt Enterprises
Mike Dolt Enterprises
User: ceb58, Location: Raeford, NC
Asked on: Tuesday, March 15, 2011 at 2:28 pm EDT
Answered on: Tuesday, May 14, 2024 at 2:49 am EDT
Question: In looking over the changes in the 2011 I want to make sure I have it correct.338.10 (B)(4)(a) is now stating that the amp rating of SE can now go back to the 75 deg column as long as it is not installed in thermal insulation.So dose this mean that if you install a 200 meter/combo with feed through lugs and the SER doesn't run through thermal insulation we can go back to using 4/0al or doing 2 back to back panels on a 320amp service as long as 240.4 is met?
Yes, you have the correct interpretation.Article 338.10(B)(4)(a) now allows for the ampacity of service-entrance (SE) cable to be based on the 75°C column of Table 310.16 if the cable is not installed in thermal insulation.This means that you can use 4/0 aluminum SE cable for a 200-amp service with feed-through lugs as long as the cable is not installed in thermal insulation. You can also use two back-to-back panels on a 320-amp service as long as the requirements of 240.4 are met (e.g., the panels are mounted side-by-side, have a common bonding means, and have service disconnects with common trip units).
Note: The 75°C column of Table 310.16 is based on an ambient temperature of 30°C (86°F). If the ambient temperature is higher, then the ampacity of the SE cable must be adjusted accordingly. Flag for review