Code Panel Questions & Answers 2014

WESTERN SECTION IAEI

CODE PANEL QUESTIONS & ANSWERS 2014

1. An installation consists of a breaker–breaker 480v series rated system and a industrial controller. The line side breakers are 65k, the downstream panel contains 14k AIC breakers. The fault current at the downstream panel is 28,000. Next to the downstream panel attached by a close nipple is an industrial controller that was a field evaluated an issued a 14k sccr. The fault current is approximately 25,000 at the line terminals of the controller. Is this controller protected and NEC compliant since it has the same rating as the breakers in the panel? If not what is a solution?

2. Does a UPS require a disconnecting means ahead of it and within sight? Is the UPS considered an appliance for installation guidelines?

Reference 645.11, 700.12(C), 701.12(C) and the Definitions in 100

This is a difficult question to answer. Personally, I would say yes that you would need a disconnect before the UPS to isolate it from the power source. You would also need a disconnect between the UPS and the piece of electrical equipment that might need to be serviced.

However, I could not find a section within the code that made this statement generally. I did find the reference in 645.11 that require disconnects and in 700.12(C) and 701.12(C) states that the UPS needs to be treated as a Battery and Generator Set where 700.12(B)(6) 701.12(B)(5) for Outdoor Generators Sets require a disconnect. As NFPA always stated: We look forward to your Public Input.

Is an UPS consider an Appliance?

I would say maybe. If it is a cord and plug piece of equipment I would say yes and the disconnect could be accomplished by unplugging the UPS per 422.33. Otherwise the UPS is a piece of electrical equipment.

Article 100 defines the following:

Appliance. Utilization equipment, generally other than industrial, that is normally built in standardized sizes or types and is installed or connected as a unit to perform one or more functions such as clothes washing, air-conditioning, food mixing, deep frying, and so forth.

Uninterruptible Power Supply. A power supply used to provide alternating current power to a load for some period of time in the event of a power failure.

Informational Note: In addition, it may provide a more constant voltage and frequency supply to the load, reducing the effects of voltage and frequency variations.

UPS systems do not alleviate the need for a generator or second utility service power source, but they do serve to buffer critical loads from the effects of generator starting time and voltage and frequency variations.

3. UL stands behind their reducing washers even when over 250v if they are installed by removing all rings in a concentric. If we have an installation that is 120v or208v and use a reducing washer in a disconnect but do not remove all the rings is it now required to install a bonding bushing?

Answer: NEC 250.96(A), 110.3(B), UL White Book, QCRV, Pg. 392

Yes, NEC 250.96 (A) requires the enclosure to be bonded and remove the paint from the effected area. See Outlet Bushings and Fittings (QCRV) in the UL White Book that states: GROUNDING

Metal reducing washers are considered suitable for grounding for use in circuits over and under 250 V and where installed in accordance with ANSI/NFPA 70, "National Electrical Code." Reducing washers are intended for use with metal enclosures having a minimum thickness of 0.053 in. for non-service conductors only. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been certified for bonding purposes may be used with reducing washers without all knockouts being removed.

4. Under the 2014 NEC, do I now have to have a grounding electrode system for roof top solar arrays? Are ground rods required?

Answer: Yes. You did not ask, but I’ll answer anyway (Do I have to have an auxiliary grounding electrode system…Yes). Are ground rods required…No.

Code Reference: 690.47(A); 690.47(B); 690.47(C)(1), (2), or (3); 690.47(D)

An auxiliary grounding electrode system is required to be installed in accordance with 250.52 and 250.54 at all ground- and pole-mounted PV arrays and as close as practicable to roof-mounted PV arrays.

The large quantity of conductive material that is added to a roof when a PV system is installed increases the likelihood of a lightning strike. This PV grounding electrode system would help to minimize the effects of such a lightning strike. The purpose of this PV grounding electrode is two-fold. The primary purpose is to maintain the frames of the PV array to as close to local earth voltage potential as possible. This is favorable to relying on a potentially long equipment grounding conductor back to a grounding electrode perhaps on another structure. This situation presents a potential shock hazard and necessitates these PV arrays be grounded to a local grounding electrode. The secondary purpose of this PV grounding electrode is to provide a simple and direct path to earth for any static charge that may build up in storm or lightning activities.

The term “Auxiliary” was added to the title and reference in the text along with a reference to 250.54 to indicate that this PV grounding electrode system is not required to be tied into the premises grounding electrode system. This tie-in with auxiliary grounding electrodes will also make it clear that if multiple PV “auxiliary“ grounding electrodes are installed, they do not need to be bonded together by a dedicated bonding jumper. These grounding electrode(s) will be permitted to be connected to the equipment grounding conductors of the branch circuit(s) or feeder(s) to these PV arrays.

5. A 200- amp main breaker for a home is installed on the exterior of the house and from there a 4/0 aluminum SER cable rated at 75 degree is installed to the sub-panel (main feeder). The cable is run in a insulated area of the floor joists. Is the ampacity of the cable determined at 60 degrees because Art- 338.10 (B) 4 or does Informational note #2 allow the use of table 310.15 (B) 7 and the 4/0 cable is good for 200 amps?

Answer: The statements in the question are not exactly true but yes you can feed the sub-panel in this question with the 4/0 Alum SER 4 plex. 338.10(B)(4)(a) interior installations must comply with Article 334 Part 2 except for 334.80, therefore the ampacity limitations for NM cable do not apply to SER.

6. Are the conductors between a 30 amp breaker and a 30 amp fused disconnect feeding a single air conditioning unit defined as a feeder or a branch circuit? Would the answer change if the fuses in the 30a disconnect are reduced to 20 amps to meet the nameplate rating of the equipment?

Reference: NEC 100 – Feeder / Branch Circuit

Answer: Q1) Yes it is a Feeder

Q2) No

7. What size equipment bonding jumper is required to connect a 125-volt, 20-amp duplex receptacle, located in the patient care area, to the patient equipment grounding point of a critical care area located in a health care facility?

Answer: Equipment bonding jumper connected to the grounding point shall not be smaller than # 10 AWG

Reference: 2014 NEC 517.19(D) 2011 NEC 517.19(C)

Reference grounding point is defined at 517.2 as “The ground bus of the panelboard or isolated power system panel supplying the patient care area.”

Though an optional feature a patient equipment grounding point continues to be provided by many hospital equipment manufacturers and is specified by consulting engineers. The objective is to reduce any potential difference between conductive surfaces in the patient care vicinity. Also see NFPA 99:3.3.141

8. Is it permissible to install an 8” piece of ¾” EMT with set screw connectors between the bottom of a panel (below live parts) and a 3R pull box installed outdoors?

Reference: NEC 314.15 and 110.3(B), 2014 UL White Book, Pg. 174, Electrical Metallic Tubing Fittings (FKAV)

Answer: No, See NEC 314.15, which states that in damp or wet locations, “Boxes, conduit bodies, outlet box hoods, and fittings installed in wet locations shall be listed for use in wet locations.” A set screw fitting would not be Listed as a suitable for wet locations or rain tight. See EMT Fittings (FKAV) in the 2014 UL White Book.

9. A 400 amp service is installed using 500 KCMIL copper conductors. Based on table 250.66 a 1/0 copper conductor is required for the grounding electrode conductor. Is it permissible to instead install 2- #2 AWG copper conductors in parallel instead of the single 1/0 for the GEC?

See 250.62 for the material permitted for grounding electrode conductors. There is no provision in Article 250 for parallel grounding electrode conductors.

10. We have an Eaton panelboard that does not recognize a 208v three pole breaker to be series- rated with a Type ( J ) fuse. Could we install three single pole breakers and use a listed 3- pole tie handle to achieve the series rating?

225.33(B) Single-Pole Units. Two or three single-pole switches or breakers capable of individual operation shall be permitted on multiwire circuits, one pole for each ungrounded conductor, as one multipole disconnect, provided they are equipped with identified handle ties or a master handle to disconnect all ungrounded conductors with no more than six operations of the hand.

Article 100 Definitions

Identified (as applied to equipment). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.

11. We have multiple roof top exhaust fans that have starters controlling them. These starters are “hand/ auto/ off” type with heaters and fuses in them. A common practice is to locate these controllers above the ceiling below the units that are on the roof. Is this location permissible?

Reference: 404.8(A) Exception Number 2, 430.2, 430.102

Yes, 404.8(A) Exception Number 2, allows for motor controllers (switches) to be located higher than 2.0 meters and to be accessible by portable means.

430.2 Controller. For the purpose of this article, a controller is any switch or device that is normally used to start and stop a motor by making and breaking the motor circuit current.

Switch, Motor-Circuit. A switch rated in horsepower that is capable of interrupting the maximum operating overload current of a motor of the same horsepower rating as the switch at the rated voltage.

430.102 states that the requirements for the disconnects for the motor and the controller. However, it does not state where the controller is permitted to be installed.

12. UL requires exhaust fans that are in a damp location to have GFCI protection. Is the exhaust fan for a residential or commercial hood considered to be in a damp location?

Answer: Reference: Art. 100 Definition of Damp Location, NEC 110.3(B)

No, the definition of Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Informational Note: Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.

Look at the installation provided with the Listed Hood.

13. Can a listed deck box for pool lights be located in a wall with an access cover for aesthetic reasons?

Answer: No

Code Reference: NEC 314.20; 314.29; 680.24(A)(2)(c); and 110.3(B)

I could not find a listed flush deck box for an Article 680 environment that was listed as a swimming pool junction box and identified to be installed in an orientation other than horizontal flush in the deck.

314.20 requires boxes in walls or ceilings to have the front edge of the box to not be set back more than 6 mm (¼ in.). from the surface. It would seem that the aesthetic access cover over the flush deck box would be set the deck box back more than 6 mm (¼ in.) from the surface of the wall.

314.29 requires boxes to be installed so that the wiring contained in them can be rendered accessible without removing any part of the building or structure.

14. We have a 6- story building with about 20 low- voltage cabinets installed in 10 different locations; most of them are for 24v card readers. Is it required to ground or bond every low voltage cabinet that contains low voltage cables for these card readers?

Answer: Yes if supplied by a Transformer if the supply system exceeds 150V

NEC 725.133 must comply w/ 725.135 and 143 Grounding is not covered 250.3 250.112(I) and 250.20(A)

15. Does a 480-volt, 1600-amp frame breaker with an 800-amp trip plug installed require GFCI protection?

Reference: NEC 230.95

The rating of the service disconnect shall be considered to be the rating of …. the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted.

Answer: No

16. When the travelling carnival comes to town, they have a couple of distribution panels located throughout the carnival site. From these distribution panels a feeder ranging from a 60a 3 pole to a 20a 2pole are run to each ride controller. These controllers then supply the rides that typically have motors & lights. Is it required to install an electrode at each controller?