110.26 Working Spaces above Lay-in Ceilings (VAV Boxes)

[SparkyEngineer]

We have recently run across some issues in the field with the AHJ citing the VAV boxes not having 42" clear in front of the control panel (boxes contain 480V electric heaters and 277V fans). Typically most jurisdictions have just required sufficient "access" to the mechanical equipment and not "working space" as required for electrical equipment such as switchgear, panelboards, MCCs and similar. That said, I certainly can see where a VAV box would be "likely to require examination, adjustment, service, or maintenance while energized", if nothing else to check voltages.

From experience, this is always the grey area of 110.26 as by default equipment above the ceiling is usually accessed off of a ladder and thru a 2'x2' suspended metal ceiling grid which means you almost never have more than 2' clear area anyway.

Any thoughts on this?

 

[SparkyEngineer]

No comments? Has anyone run across this interpretation/issue?

 

[Dennis Alwon]

It is a gray area and really up to the inspector. Obviously it is next to impossible to have a disconnect meet those requirements. IMO, a disco does not need the clearance however a VAV box does need adjustment and may be considered necessary to have clearance. I am not sure what choice there is in making the box more accessible. It does not seems to be a realistic demand.

 

[Smart $]

IMO, your VAV's are not electrical equipment. They are...

Utilization Equipment. Equipment that utilizes electric
energy for electronic, electromechanical, chemical, heating,
lighting, or similar purposes.

Additionally, electrical equipment is part of and facilitates a...

Premises Wiring (System). Interior and exterior wiring,
including power, lighting, control, and signal circuit wiring
together with all their associated hardware, fittings, and
wiring devices, both permanently and temporarily installed.
This includes (a) wiring from the service point or power
source to the outlets or (b) wiring from and including the
power source to the outlets where there is no service point.
***Such wiring does not include wiring internal to appliances,
luminaires, motors, controllers, motor control centers,
and similar equipment.

 

[Dennis Alwon]

IMO, your VAV's are not electrical equipment. They are...

I guess that is the million dollar question.

 

[SparkyEngineer]

That is indeed the issue.

If a VAV box is not required to have clearance, then what about roof-mounted equipment, air handlers in mechanical rooms and the like?

Another interesting twist can be found from looking at 670.5 in the 2002 NEC. This section is on clearance for industrial machinery (similar to HVAC equipment) and allows for a reduced working space (to 2-1/2') where "conditions of maintenance and supervision ensure that only qualified persons service the installation...". That means at some point it was clearly the intent for the code to apply to these pieces of packaged equipment.

:?

 

[Dennis Alwon]

When I met with the members of the code making panel at our annual meeting in Raleigh and ask whether an a/c disco needs to meet the clearances, they all agreed that it did. When I asked how we can maintain the 6'6" required by 110.26(E) when the unit is in a crawl space or a dropped ceiling they all had blank looks on their faces. Obviously they never thought about that.

 

[SparkyEngineer]

Thanks for everyone's input. At least I feel better knowing that others have struggled with this grey area of the code.

 

[kwired]

IMO, your VAV's are not electrical equipment. They are...

Utilization Equipment. Equipment that utilizes electric
energy for electronic, electromechanical, chemical, heating,
lighting, or similar purposes.

Additionally, electrical equipment is part of and facilitates a...

Premises Wiring (System). Interior and exterior wiring,
including power, lighting, control, and signal circuit wiring
together with all their associated hardware, fittings, and
wiring devices, both permanently and temporarily installed.
This includes (a) wiring from the service point or power
source to the outlets or (b) wiring from and including the
power source to the outlets where there is no service point.
***Such wiring does not include wiring internal to appliances,
luminaires, motors, controllers, motor control centers,
and similar equipment.

I like this approach.

A lot of utilization equipment will have problems if you tried to apply 110.26 just by nature of the equipment and places it is commonly located.

I will try to remember that next time anyone gives me crap about needing 110.26 clearance for anything that is not premises wiring.

A big one (I don't have any problems with inspectors with it) that I hear sometimes is breakers included in HVAC equipment. Since it is not premises wiring 110.26 doesn't apply to it. If manufacturers instructions or the listing of the unit require the space that would be reason to provide it, not 110.26.