CFLs, Permanent Generators and More

Article 110 Requirements for Electrical Installations; Article 250 Grounding and Bonding; Article 300 Wiring Methods; Article 517 Health Care Facilities; Article 547 Agricultural Buildings; Article 695 Fire Pumps; Some parts of the Guide Information for Electrical Equipment Directory (White Book) 2008 edition published by Underwriters Laboratories Inc. also are mentioned.

CFLs in incandescent luminaires

Am I in violation of Section 110.3(B) by installing compact fluorescent Edison screw-type lamps in listed incandescent luminaires? May they be installed in listed totally enclosed recessed incandescent luminaires?

Yes, compact fluorescent self-ballasted fluorescent lamps (CFL) may be installed in incandescent luminaires provided that they fit and the wattage of the fluorescent lamp does not exceed the maximum wattage marked on the luminaire.

At present, the most popular type of self-ballasted fluorescent lamp has a spiral shape with a rating of 13 watts. This lamp may be installed in totally enclosed incandescent luminaires, provided the trim can be replaced after the lamp is installed. These lamps will fit into some 6- and 8-inch recessed luminaires.

If the luminaire is in a damp location, the lamp must be marked suitable for a damp or wet location.

These self-ballasted fluorescent lamps may not be acceptable in exit and emergency luminaires where brightness may be reduced.

Installing self-ballasted fluorescent lamps is not a violation of 110.3(B) because Underwriters Laboratories Inc. recognizes these lamps in the Guide Information for Electrical Equipment Directory (White Book) under the category “Lamps, Self-Ballasted and Lamp Adapters (OOLR).” Part of the introduction states: “These products are generally for use in indoor, dry locations unless additionally investigated and marked for applications such as damp locations (not directly exposed to water). Products investigated and marked for wet locations may have additional restrictions regarding use or orientation.”

Another paragraph reads: “These products have been investigated for use in the smaller of a 6- or 8-inch diameter recessed luminaire, if they will physically fit and are intended for use in totally enclosed recessed luminaires unless marked and stated not for such use.”

For more information on the proper use of self-ballasted fluorescent lamps, see page 232 in the 2008 issue of the White Book.

Grounding permanent generators

What sections of the National Electrical Code (NEC) provide requirements for grounding a permanently installed generator that supplies loads in a one-family residence?

The generator neutral conductor must be grounded where the voltage is 120/240 volts, three-wire, single phase and the system supplies premises wiring and loads. Section 250.20(B) (1) requires this. Item (2) of 250.26 requires that the neutral conductor of a three-wire, single-phase system be grounded.

Where the generator supplies more than one enclosure, the main bonding jumpers cannot be smaller than required by 250.66 to comply with 259.28(D).

A grounding electrode and grounding-electrode conductor must be connected to the neutral at the generator and the grounding electrode, which could be buried metal water pipe or a structural grounding electrode. The grounding electrode should be as close as practical and preferably in the same area as the generator. Where these electrodes are not available, any other electrodes in 250.52(A) may be used.

If the transfer switch is two-pole and the neutral is not switched, a grounding electrode and grounding-electrode conductor are not required for the generator. This is explained by Fine Print Note No. 1 following 250.20(D).

Where the neutral of the generator is switched with a three-pole transfer switch, the neutral must be grounded with a grounding-electrode conductor and grounding electrode. If the grounding electrode is 10 feet or more of buried metal water pipe, the grounding--electrode conductor must be sized to comply with Table 250.66. If the grounding electrode is a concrete-encased electrode, the grounding-electrode conductor does not have to be larger than 4 AWG copper.

Power supply for jockey pump

Can the jockey pump for a fire pump installation be supplied from the normal building electric power source, or must the jockey pump be fed from the fire pump service?

The pressure maintenance pump may be supplied from the normal electrical supply to the building or from the service that supplies the fire pump. Either power source is acceptable. The pressure maintenance pump motor is permitted to be connected to the fire pump service by 695.3(A), but is not required to be connected to this power source.

The pressure maintenance pump motor is permitted to be connected to the normal power source, and the rules in Article 430 apply to the wiring and equipment that are part of the motor branch circuit. In other words, there are no special requirements for wiring a pressure makeup pump unless the pump is connected to the fire pump electric supply.

If the pressure maintenance pump is supplied from the fire pump electric source, the overcurrent-protective device(s) must be sized to carry indefinitely the sum of the locked rotor currents of the fire pump motor and the pressure maintenance pump to comply with 695.4(B)(1).

Bathroom branch circuit

May the branch circuit that supplies a -receptacle in the bathroom in a multifamily building also supply the exhaust fan and lighting in that bathroom?

Where two or more bathrooms are supplied from the same branch circuit, Article 210.11(C)(3) of the NEC permits only receptacles to be connected to the branch circuit. Where a single 20-ampere branch circuit supplies one bathroom, other outlets in the bathroom are permitted to be supplied from this branch circuit. The exception to 210.11(C)(3) permits this.

Type MC cable in patient care areas

May Type MC cable be used to supply receptacles in patient care areas of a hospital?

Some types of MC cable are suitable for this application. Section 517.13(A) requires the wiring method to provide a ground return path, plus an equipment-grounding conductor, along with the branch-circuit conductors supplying the receptacles. The requirement in 517.13(A) states: “All branch circuits serving patient care areas shall be provided with an effective ground-fault path by installation in a metal raceway system or a cable having a metallic armor or sheath assembly. The metal raceway system, or the metallic cable armor, or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118.”

According to the Guide Information for Electrical Equipment Directory with regard to metal-clad cable (PJAZ), “The metal sheath is an interlocked metal tape, a corrugated metal tube or a smooth metal tube.” A few sentences later, the guide states: “Cable with interlocked armor that has been determined to be suitable for use as a grounding means has interlocked aluminum armor in direct contact with a single full-sized bare aluminum grounding/bonding conductor. This cable is marked to indicate that the armor/grounding conductor combination is suitable for ground.” This type of interlocked armor MC cable with an equipment-grounding conductor in addition to the bare bonding conductor may be used to wire receptacles in a patient care area of a hospital.

The sheath of the corrugated-tube or smooth-tube Type MC cable with an insulated green grounding conductor is also a suitable wiring method for receptacles in a patient care area. However, if the smooth or corrugated tube MC cable also contains a bare equipment-grounding- conductor not in contact with the armor, the armor is not an equipment--grounding conductor and the cable cannot be used to supply receptacles in a patient bedroom of a hospital.

Panelboards and animal confinement

What type of panelboard enclosure is required in a building that has pens for animals and a show area for the remainder of the building?

Without knowing what animals will be in the pens, it is not possible to recommend the type of enclosure required for the distribution equipment necessary to satisfy Article 547—Agricultural Buildings. Two atmospheres are mentioned in 547.1(A) and (B) and are defined as those with excessive dust and those with dust with water and corrosive atmospheres. Enclosure types that may be needed are listed in Table 110.20 and include the following protection against these environmental conditions: hosedown types 4, 4X, 6, 6P; corrosive agents 3X, 3RX, 3SX, 4X, 6P for outdoor installations. For indoor use, where there is settling dust, lint, fibers, and flyings, 4, 4X, 5, 6, 6P, 12, 12K, 13; for corrosive agents, use 4X and 6P.

Fuses and circuit breakers must be installed in enclosures that are suitable for the environment in one of the enclosure types listed above. These requirements are mentioned in Sections 547.5(C) and 547.6. Pay attention to the fine print note following 547(C)(3), which indicates that aluminum and magnetic ferrous materials may corrode in agricultural environments.

Increased service and use of MC cable

Does the swing of the door have to be changed and panic hardware have to be provided on the access door to the electrical equipment room? The service to an existing building is to be increased from 1,000 amperes to 2,000 amperes. Must MC cable be installed in metal raceways where installed underground in the building? This cable, which is suitable for direct burial, will be installed between the utility transformer outside of the building to the service switchboard in the building.

Because the 2,000 ampere service is new, the edition of the NEC that is currently being enforced must be complied with. To comply with the 2008 NEC, if the new switchboard is more than 6 feet wide, the working space must conform to the requirements in Table 110.26(A)(1), and two doors must be provided. Or, if the working space is twice the dimensions in the table, one door that swings outward and is provided with panic hardware that meets the requirements of 110.26(C)(3) is necessary.

One or two doors must open in the line of egress and be equipped with panic bars, pressure plates or other devices that are normally latched but open under simple pressure.

Type MC cables that are suitable for encasement in concrete may be directly buried, but they must be installed in raceways where they enter under a building. This is required by 300.5(C).

FLACH, a regular contributing Code editor, is a former chief electrical inspector for New Orleans. Questions can be sent to

About the Author

George W. Flach

Code Q&A Columnist
George W. Flach was a regular contributing Code editor for Electrical Contractor magazine, serving for more than 40 years. His long-running column, Code Q&A, is one of the most widely read in the magazine's history. He is a former chief electrical in...

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.