For common, general terms used but not defined in the National Electrical Code, we rely on the dictionary.

Section 210-70(a)(3) of the 1999 National Electrical Code states, in part: "(3) Storage or Equipment Spaces. For attics, underfloor spaces, utility rooms, and basements, at least one lighting outlet containing a switch or controlled by a wall switch shall be installed where these spaces are used for storage or contain equipment requiring servicing. At least one point of control shall be at the usual point of entry to these spaces…."

The application of this requirement to a utility room in a dwelling has been questioned. How large must a closet be before it becomes a room?

Whether or not a light should be placed in a utility room may not seem significant, but to a contractor who has bid a multiunit project without the light, it could become very significant indeed if the inspector later decides that lights are required.

The room under consideration is a small room, indicated on the plans as a "storage room." It contains no equipment requiring servicing. We are so used to using the term "utility room" to mean that the room contains some electrical or mechanical equipment. However, lacking a definition in Article 100 of the NEC, common dictionary terms apply. "Utility" simply means "useful"; "room" means "space that is or might be occupied by something."

One rule of thumb used to distinguish a closet from a room is this: Can the door be closed behind a person after entering the space? If so, it is a room.

There are other distinctions between a room and a closet. A linen closet is a space that a person cannot enter, which is often completely filled with shelving that reaches inside the door. On the other hand, a clothes closet is often a walk-in closet that requires a light and to which no one objects.

There is another consideration: If it is determined that the storage room does require illumination, can that be supplied from outside the room as it can be for service equipment, etc. Sec. 110-26(d) says, in part: "(d) Illumination. Illumination shall be provided for all working spaces about service equipment, switchboards, panelboards, or motor control centers installed indoors. Additional lighting fixtures shall not be required where the work space is illuminated by an adjacent light source."

If illumination from outside the space is acceptable for service equipment and panelboards, why would it not be acceptable for a small storage room?

The wording of Sec. 210-70(a)(3) raises another point. In the first sentence, it is permitted that the required lighting outlet could be "containing a switch." (Actually, the fixture, not the outlet, would contain the switch.)
The second sentence requires that "at least one point of control shall be at the usual point of entry to these spaces."

Does this mean that in a room containing equipment requiring servicing, a pull-chain fixture could be located at the equipment and a string from the pull-chain running to a screw eye at the entry to the room be permitted as the point of control at the entry? No, I don't think so either, but the words can be so interpreted.

Now for something completely different.
Is there a conflict between Sec. 384-14(b) and 384-16(b)?

"384-14(b) Power Panelboard. A power panelboard is one having 10 percent or fewer of its overcurrent devices protecting lighting and appliance branch circuits."

"384-16(b) Power Panelboard Protection. In addition to the requirements of Section 384-13, a power panelboard with supply conductors that include a neutral and having more than 10 percent of its overcurrent devices protecting branch circuits rated 30 amperes or less shall be protected on the supply side by an overcurrent protective device having a rating not greater than that of the panelboard."

384-14(b) defines a power panelboard as one having 10 percent or fewer of its overcurrent devices protecting lighting and appliance branch circuits, so how can 384-16(b) speak of a power panelboard having more than 10 percent of its overcurrent devices protecting 30-ampere-or-less branch circuits?

Part of the answer is in the new definition in Sec. 384-14(a) of a lighting and appliance branch circuit as one of 30 amperes or less and having a connection to the neutral. A careful reading is necessary to distinguish between 384-14(b) and 384-16(b), but it appears to be this: In 384-14(b) a power panelboard is defined as having 10 percent or fewer overcurrent devices protecting circuits having neutral connections, whereas 384-16(b) speaks of a power panelboard having more than 10 percent of its overcurrent devices protecting circuits of 30 amperes or less, but not necessarily having neutral connections.

The feeder contains a neutral, but the branch circuits may or may not contain a neutral. It appears that the 1999 changes were intended to require the same overcurrent protection for a power panelboard as for a lighting and appliance branch circuit panelboard, when more than 10 percent of the branch circuits served are 30 amperes or less.

This question then arises: What if the more-than-10-percent, 30-ampere-or-less branch circuits in the panelboard include neutral conductors? By the definition of 384-14(a), it is a lighting and appliance branch circuit panelboard. Surely, the intent could be more clearly and more simply worded.

SCHWAN is an electrical code consultant in Hayward, Calif. He can be reached at bev-schwan@aol.com.