Mike Dolt Enterprises
Mike Dolt Enterprises
User: cdcengineer, Location: New Jersey
Asked on: Friday, March 18, 2011 at 4:38 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:00 am EDT
Question: I have a question...The scenario. A 800A 208Y/120V MDP in the main electrical room feeds thru a 400A feeder breaker to section 1 of a 2-section panel HP1-S1 which is 400A main lug with feed thru lugs (this panel lives on the first floor elec closet serving branch lighting and power)..Any reason why HP1-S1 cannot feed a second section HP1-S2 which will be a 400A, main lug (living in the 4th floor elec closet) fed from the feed thru lugs in section 1?The question is can I use the feed thru lugs and locate the second section in a completely separate room on a different floor? Usually I see 2-section panels living side by side.Thx
Yes, you can use the feed-thru lugs in section 1 of the HP1 panel to feed a second section, HP1-S2, located in a separate room on a different floor.
NFPA 70 (NEC) Requirements
408.16(A) Feed-Through Neutral Bars
Feed-through neutral bars shall be permitted to supply branch circuits on both sides of the panelboard.
408.16(B) Feed-Through Grounding Bars
Feed-through grounding bars shall be permitted to supply grounding conductors for branch circuits on both sides of the panelboard.
408.24(C) Feeder Arrangement
Where the feeder supplies additional panelboards, as permitted in 408.24(A), the feeder conductors shall terminate on the line side of the terminals or lugs that supply the branch circuits.
Considerations
Voltage Drop
Ensure that the voltage drop within the second section is within the allowable limits for the branch circuits being supplied.
Conduit and Wiring
Provide appropriate conduit and wiring to accommodate the feeder conductors and branch circuit conductors within the second section.
Load Balancing
In a two-section panel, load balancing between the two sections is important to prevent overloading. Consider distributing the branch circuits evenly across the sections.
Short-Circuit Current Rating
The section panelboards must be listed for the short-circuit current rating of the feeder supplying them.
Grounding and Bonding
Ensure proper grounding and bonding of the second section panelboard to the electrical system and to the building structure.
Advantages
Allows for flexibility in distributing power to different areas of the building. Can save on installation costs by using a single feeder and feed-thru lugs instead of multiple feeders.* Provides a convenient way to expand the panelboard capacity in the future.
Conclusion:
Provided that the necessary considerations and requirements are met, it is acceptable to use the feed-thru lugs in section 1 of the HP1 panel to feed a second section, HP1-S2, located in a separate room on a different floor. Flag for review