Q
I am in a disagreement with a customer over installing light fixtures in clothes closets. The clothes closets in question are 48 in. to 60 in. wide, 8 ft high and 24 in. deep, with a clothes-hanging rod 6 ft from the floor with a 12-in. wide shelf directly above the rod.
In my opinion, it is a violation to install any type of fixture within these closets. Section 410-8 (d)(1), which states that incandescent fixtures are required to be 12 in. from storage spaces — with a 12-in. shelf and a 12-in. clearance — prohibits this type of fixture. While 410-8 (d) (2) permits fluorescent fixtures with a 6 in. restriction, this type of fixture would leave little room for installation.
A
You are correct that the requirements in Section 410 8(d)(1) do not allow a surface-mounted incandescent fixture in your closet. This section requires a clearance of 12 in. from the storage space. It would not be possible to maintain the required 12 in. with a ceiling-mounted or wall-mounted incandescent fixture.
Section 410-8(d)(2) allows a wall- or ceiling-mounted fluorescent fixture with a clearance of only 6 in. from the storage space. You should be able to locate a small fluorescent fixture that would satisfy Section 410-8(d)(2).
Sections 410-8(d)(3) and (4) recognize the use of ceiling- or wall-mounted recessed fixtures. Sections 410-8(d)(3) and (4) allow an incandescent or fluorescent fixture. In this case a clearance of 6 in. is required. You may be able to locate a fixture small enough to allow ceiling mounting. Both types would work if they are wall-mounted above or beside the door. If an incandescent fixture is used, the lamp must be completely enclosed.
Dann Strube
Q
We have a service that is 400A 120/240V one-phase. From the self-contained meter it goes into a trough and splits into three 200A disconnects (two 200A circuit breaker disconnects; one two-phase/two manual switch for a generator in a farm application).
Question and problem:
What regulates the use of three 200A disconnects on a single 400A service?
The owner wants me to relocate the feeders to the one 200A breaker disconnect to the load side of the double-throw switch. That would put (we'll say) two 200A services on one 200A, double-throw, non-fusible, service-rated switch.
It doesn't sound like a good idea but his combined loads aren't over 160A. Can you tell me what sections in the Code would regulate this?
A
Section 230-79 requires the rating of the service disconnect to be not less than the calculated load. When there is more than one disconnect, the combined rating (the sum of the ratings) has to be at least equal to the calculated load.
The general rule in Section 230-90 states that each ungrounded conductor must be protected from overload by a device rated not more than the ampacity of the conductors. However, 230-90(a), Exception No. 3 permits the sum of the ratings of a group of disconnects to exceed the rating of the service conductors as long as the conductors are big enough for the calculated load.
It sounds like you have something less than 360A of load on your 400A service, so the sum of the disconnects (600A) may exceed the rating of the service conductors (400A). This rule assumes that anyone adding load will recalculate the load in order to stay in compliance with the Code.
You do not say how the conductors attached to the transfer switch are protected from overcurrent. You must provide the overcurrent protection required by 230-90 for service conductors, and by 215-3 for feeders.
Since you have a farm application, you can use Section 547-8 to determine the arrangement of disconnects, overcurrent protection and grounding, and one permitted arrangement allows the overcurrent protection to be located at other feeder disconnects at other structures.
You are probably dealing with an optional standby system, so Article 702 applies. This permits the manual transfer switch. Emergency systems and legally required standby systems require automatic transfer.
Section 702-5 allows you to determine what will be supplied by the system and requires only that the equipment be adequate for the selected load.
The other common concern would be terminations in the switch. The switch must have terminals suitable for two conductors or space adequate to make splices in accordance with Sections 110-14 and 373-8.
The key to this all being acceptable is that you have less load than the ratings of the conductors, switches and overcurrent devices, and that none of the required components is eliminated by the proposed rearrangement.
Noel Williams
Dann Strube is a nationally recognized NE Code expert and electrical code consultant.
Greg Bierals is president of the Electrical Design Institute, Davie, Fla.
Noel Williams is licensed as an electrical inspector in Utah and is co-author of the NFPA's 1999 NE Code Changes.
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