Mike Dolt Enterprises
Mike Dolt Enterprises
User: mshields, Location: Boston, MA
Asked on: Tuesday, March 29, 2011 at 6:11 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:27 am EDT
Question: I've got a shallow electrical closet with double doors that only afford me 5 feet clear. I need to get three panelboards in this closet. If touching each other, I make the clearance just barely, but that doesn't even allow for a door hinge cutting into that space by a fraction of an inch.What I'm considering is using column type panelboards but I've never done this before and want to make sure I'm considering all that needs to be considered here. One concern is getting all the conduit out the top of these things. It will need to be conduit and not MC because these are Emergency panels in a hospital. I'm thinking I can probably make this work, but combining circuits in larger conduit where exiting the panelboard, running to a box above and then running the individual circuits from that box.Would be interested in your thoughts?Thanks,Mike
Considerations for Using Column Panelboards Clearance
Column panelboards offer significant space savings compared to traditional panelboards, allowing you to achieve the required 5 feet of clearance even when the panels are touching.
Conduit Routing
Column panelboards typically have conduit knockout locations only at the top, which can be a challenge for routing conduit out of the closet. However, as you mentioned, you can use junction boxes above the panelboards to combine circuits into larger conduits and then run individual circuits from there.
Feeder Wiring
Since the panelboards will be touching, you will need to pay special attention to the feeder wiring. Ensure that the feeders are not touching the panelboard enclosures and that there is adequate space for termination.
Access
Column panelboards can be more difficult to access compared to traditional panelboards. Consider the location of the disconnect switches and if there is sufficient room for maintenance and troubleshooting.
Design Considerations Conduit Layout
Plan the conduit routing carefully to avoid any potential interference with the panelboard enclosures or conduit knockouts.
Junction Box Placement
Determine the optimal location for the junction boxes above the panelboards to minimize conduit lengths and maintain accessibility.
Circuit Combining
Group circuits in the junction boxes based on their load characteristics and conduit size requirements.
Feeder Sizing
Calculate the feeder sizes based on the total load of the combined circuits and ensure that the conductors are properly rated for the voltage and current requirements.
Labeling
Clearly label all circuits, conduits, and junction boxes for easy identification and maintenance.
Additional Tips Consult with an electrical engineer to ensure compliance with applicable codes and standards. Plan for future expansion by providing additional knockouts or spare conduits in the junction boxes. Use locknuts and sealing washers to ensure proper grounding and watertight connections. Allow for ample headroom above the panelboards for conduit installation and cable bending. Consider using a short-circuit current rating (SCCR) that is higher than the available fault current at the location. Flag for review