SOME REVIEW - QUESTIONS 2011 NATIONAL …

1 some REVIEW - QUESTIONS 2011 NATIONAL electrical CODEJ & W Educational Services1340 Hickory Hill , Ga 30677 Jim Allison(706) is the Code rule regarding neutral conductors at switches?Switches controlling line-to-neutral lighting loads must have a neutral provided at the switch location [ (C)].Exception: The neutral conductor isn t required at the switch location if: conductors for switches enter the device box through a raceway that has sufficient cross-sectional area to accommodate a neutral conductor. assemblies for switches enter the box through a framing cavity that s open at the top or bottom on the same floor level, or switches enter the box through a wall, floor, or ceiling thatis unfinished on one sideHint 404 One of my guys put two uninsulated conductors undera single screw on the bonding bus.

2 The inspector saidthat was a code violation. Where is this in the NEC?Hint electrical Connections(A) Terminals. Connection of conductors to terminal partsshall ensure a thoroughly good connection without damagingthe conductors and shall be made by means of pressure Connectors (including set-screw type), solder lugs, or splices toflexible leads. Connection by means of wire-binding screws orstuds and nuts that have upturned lugs or the equivalent shallbe permitted for 10 AWG or smaller for more than one conductor and terminalsused to connect aluminum shall be so flexible metal conduit or surface metal raceways be used for branch circuits in patient care areas where wiring must be provided with a ground path for fault current?

3 Hint metal conduit in lengths not exceeding 6 ft can be used for branch circuit wiring in patient care areas of a healthcare facility if the circuit conductors contained in the racewayare protected by overcurrent devices rated at 20A or less. A redundant equipment grounding conductor is also necessary. In addition, (6)c points out that where the flexible metal conduit is part of the ground return path, thetotal combined length of the flexible metal conduit in that runcannot exceed 6 metal raceways are also considered suitable for grounding unless they have some marking like UL information that would prohibit its use as a sole grounding someone tell me if the NATIONAL electrical Code (NEC) limits running flexible metal conduit to any particular length?

4 I ask this because I understand Greenfield for a light fixture shall not be longer than 6 ft. I would like to know if I can extend a 7-ft run of flexible metal conduit to a (2)The NEC does restrict the length of flexible metal conduit for lighting fixtures to 6 ft to limit the ground return path. Sec. restricts the length of the motor leads between the motor and required junction box to a maximum of 6 ft, regardless of what type of conduit they are contained in this pertains to the motor leads only. The length of flexible metal conduit for other uses isn t restricted, while a grounding conductor is included with the circuit conductors. In response, the author may run any length of flexible conduit from the disconnect to the motor junction box, provided he also meets the requirements for support of the flexible conduit and location of the disconnecting other commentsIf over 6 ft must have grounding 'm installing 3-in.

5 Intermediate metal conduit (IMC) with anextended run length of about 300 ft to 350 ft. My coworkers told me I have to install a pull box about every 100 ft, but I can't find a reference to this in the NEC. Is there a rule in the Code that specifies the maximum distance between pull points?No. The Code does not specify when a pull box is required, but does specify how to properly size a pull box. You can run the raceway as long as you want, but the Code does not permit more than the equivalent of four quarter bends (360 total) between pull points [Secs. , , , , , , , and ].Hint 314I just set a service on a new house where I used -in. electrical metallic tubing (EMT) to encase the grounding electrode conductor (GEC) from the meter base to the ground rod.

6 The inspector said I have to bond both ends of the metal raceway to the GEC. He also said I should use nonmetallic conduit in the future. Is he correct?Hint According to (E), you can use a metal enclosure to encase the GEC, but you must maintain electrical continuity between the point of attachment to cabinets or equipment and the grounding electrode. You must also securely fasten it to the ground clamp or fitting and make metal enclosures that are not physically continuous from cabinets or equipment to the grounding electrode electrically continuous by bonding each end to the GEC Sec. This ensures they will be in parallel with each other. Failure to bond both ends could create a condition where the reactance of the raceway becomes so high that it creates an inductive choke that would limit the GEC's ability to carry current.

7 If you used nonmetallic conduit to encase the GEC, you don't have to worry about maintaining the electrical continuity of the metal 'm working on a project that includes hooking up a listed kiln in a ceramics classroom. The kiln is rated 100A at 208V. The flexible metal raceway from the kiln to the 100A disconnect includes two 1 AWG conductors, one 6 AWG grounded (neutral) conductor, and one 12 AWG equipment ground. I can't find a section of the NEC that allows the grounded (neutral) conductor to be reduced in size as it is. Am I missing something?Yes. There are no Code rules that specifically tell us how to size the grounded (neutral) conductor for branch circuits, but there is one for feeders ( (B)).

8 You only need to size the grounded (neutral) conductor to carry the maximum unbalanced load between it and any ungrounded conductor. Because this is a listed product, you only need to wire the appliance according tothe instructions. However, the size of the equipment grounding conductor in the flexible metal raceway is cause for concern. This equipment grounding conductor may not be smaller than shown in Table , based on the rating of the circuit overcurrent protection device. For a 100A protection device, the equipment grounding conductor may not be smaller than 8 've heard an insulated equipment grounding conductor for an isolated grounding circuit installation should float from the electrical system.

9 I've also heard it must terminate at the neutral point of a transformer or at the neutral-to-case connection point at service equipment. Which way is correct?Isolated (insulated) equipment grounding circuits must provide aneffective ground-fault current path in addition to providing a clean grounding connection for the the isolated (insulated) equipment grounding conductor serves both purposes. The required equipment grounding conductors must always be in place and effective in addition to any desired isolated (insulated) equipment grounding conductor. Where designs call for more specialized equipment grounding means for reducing unwanted electromagnetic interference on the grounding circuit, usually an additional insulated equipment grounding conductor path is installed.

10 In the patient care areas of health care facilities, where isolated (insulated) equipment grounding circuits are installed with the branch circuits, there will be three equipment grounding conductor to meet the requirements in (A) and (B) in addition to any desired isolated (insulated) equipment grounding that may be desired. A good way to approach these installations is to always strive to satisfy what is required by the minimum requirements of the NEC before applying any desired isolated (insulated) equipment grounding circuits. Safety must not be The NEC doesn't require the isolated equipment grounding conductor for electronic equipment to terminate to the neutral point of a transformer or at the neutral-to-case connection point at service equipment nor does it permit you to float the equipment grounding conductor from the electrical system [ (B) and (D)].