Mounting Panels Overhead on Mezzanine Walk-Through

[msilva94]

As part of the design, the construction firm requested I mount the Panels feeding equipment overhead on the Mezzanine Walk-Through. This walk-thru is essentially an open grate platform with safety rails. Their concern is security and manageability, they do not want the panels easily accessible to the workforce (forklift damage, tampering, etc), but they still need to be located near the equipment/serviced areas.

I informed them that the panels require a minimum of 3' clearance in front for maintenance, would prefer it the path was closed (not open grate) and that I would need to confirm with the structural team whether the weight of the panels and associated conduit could be properly supported. In response, they’ve proposed widening the mezzanine to 4' and passed the concern along to the Structural Engineer.

As far as I understand and have read in the NEC (240.24), as long as the Electrical Panel has clear working space, is accessible, and is marked accordingly this shouldn't be an issue.

I was wondering if there was anything I might need to be concerned about code and non-code wise, but it seems like a completely plausible approach?

 

[Rick 0920]

My only concern with this would be...... Is it readily accessible by NEC definition? How hard is it to get to the mezzanine? Do you have adequate working space within the voltages? Different depths of working spaces are required for different conditions.

 

[jim dungar]

I have been in many facilities, primarily food related, that mount their panels as you describe. In some cases they added a solid floor below the panel but that is not common. In one facility the incoming service switchboard was on a grated floor mezzanine some 20' feet up, accessible via a fixed in place straight ladder with a safety cage.

As long as you can get to the panels using fixed in place stairs or ladders, and you have sufficient working space, you meet the requirements of the NEC. everything else is a design consideration.

 

[msilva94]

My only concern with this would be...... Is it readily accessible by NEC definition? How hard is it to get to the mezzanine? Do you have adequate working space within the voltages? Different depths of working spaces are required for different conditions.

There may be a second floor office, with the intent there will be two entry points to the catwalk, with stairs and an elevator. If possible, I may request the mezzanine to extend so the stairwell (and possibly the elevator) have two doors—one to the offices and one to the mezzanine—ensuring accessibility. For the working space, I might convince the team to provide a wider catwalk, depending on structural support.

I think, be definition, this should be possible.

I have been in many facilities, primarily food related, that mount their panels as you describe. In some cases they added a solid floor below the panel but that is not common. In one facility the incoming service switchboard was on a grated floor mezzanine some 20' feet up, accessible via a fixed in place straight ladder with a safety cage.

As long as you can get to the panels using fixed in place stairs or ladders, and you have sufficient working space, you meet the requirements of the NEC. everything else is a design consideration.

From what you and Rick mentioned, and my reply to Rick, it sounds like by definition this should be legal and possible and I'm not missing anything.

Thank you both very much!