A. Yes. GFCI protection is required for all receptacle outlets serving the countertop areas regardless of the sink location. (Note): ALL receptacle outlets in a non-dwelling kitchen must be GFCI protected, not just the countertop receptacles. There is also no exception for cooking or refrigeration equipment. One option is to use fiberglass electrical conduit fittings.
Q. Where a PVC water line is ran to a building, is it necessary to drive two ground rods?
A. Generally no. There is no mandatory requirement to drive two rods simply because the building is supplied by a nonmetallic waterline. Where there is no metallic water line ran to the building, a water pipe electrode does not exist. Therefore 250.53(D)(2) would not apply. As long as there are no other electrodes present at the structure, one ground rod is sufficient, provided the resistance of the driven electrode is 25 ohms or less. (Note): Only where the resistance of the required driven electrode exceeds 25 ohms is an additional rod required to be driven [250.56]. The driven rods shall not be less than 6′ apart.
Q. Are vent fans required in non dwelling bathrooms with no outside window? There is no bathtub, only a sink and toilet.
A. The NEC does not address the installation requirements of exhaust fans. This topic would probably be covered in the International Building Code (IBC).
Q. If EMT conduit is used as a wiring method and an equipment grounding conductor is installed, do I have to attach the grounding conductor to a junction box located above a drop ceiling?
A. If an equipment grounding conductor is present and spliced within any box, it must be attached to the box by a screw used for no other purpose.
Q. Article 430 requires overload protection for motors of 1hp or more. Does this include motors for fire pumps?
A. No. Article 695 prohibits the use of overload protective devices for fire pumps. Ground-fault protection is also not permitted to protect fire pump motors.
Q. Is a generator a separately derived system?
A. Maybe. It depends on the transfer (xfer) switch . If the xfer switch has a solid neutral bar, the generator is not a SDS. If the neutral is switched in the xfer switch, then the generator is a SDS. The reason for this is in order to qualify as a SDS, there must be no direct electrical connection between the two systems, including the grounded conductor.
Q. Can Type MC cable be used on an isolated ground receptacle circuit?
A. Standard MC cable may not be used on an IG circuit because the metallic sheath is not listed as a ground fault current return path. There are some MC cables on the market that are suitable, such as MC/IG (isolated ground) and MC/HCF (health care facility). These cables have a redundant equipment grounding conductor (EGC) required to bond the enclosure, in addition to the EGC to the receptacle.
Q. What are the purpose of motor overloads?
A. Overloads are devices installed in series with the motors ungrounded branch circuit conductors that open in the event of an overload condition. Overloads can be caused by worn bearings, lock-ups, or loading the motor beyond capacity. The devices are not intended to protect against short circuits. The overcurrent protective device, fuses or circuit breakers, are generally only used for ground-fault, short-circuit condition, such as line to line, or line to ground faults.
Q. I know that all lights and receptacles in a dwelling bedroom are required to be AFCI protected, but what about smoke detectors and switches in the bedroom for outside lights?
A. Article 210.12(B) requires all 120V, 15 and 20 ampere branch circuits supplying dwelling unit outlets to be AFCI protected. Note: AFCI protection is not required for outlets serving kitchens, bathrooms, laundry, garages, basements or outside areas.
Q. We are wiring a warehouse and installing high bay fixtures in the building. The inspector turned us down because we hardwired the fixtures with SO cord into 4 square j-boxes on the ceiling. Is the inspector right?
A. Your inspector is correct. Article 410.30(B)(C)(1) states that flexible cords may be used only where installed in the following manner: Where installed with a male grounding type attachment plug installed on the fixture cord to plug into a receptacle outlet installed on the ceiling above the fixture, where used as part of an assembly with a canopy and strain relief or, where needed to reposition or aim an adjustable fixture. In all cases the cord must be visible for its entire length and free from physical damage.
Q. If an incoming water pipe is metal and I have plastic water piping inside, do I need a ground to the metal pipe?
A. You will need to install a grounding electrode conductor to the incoming metallic portion within 5′ of entry into the structure. The incoming piping is an electrode and the conductor shall be sized in accordance with 250.66.
Q. Are in-use covers required for 15 and 20 ampere receptacles on temporary services?
A. Yes. Article 406.8(B) requires that all 15 and 20 ampere, 125 and 250 volt receptacle outlets installed in wet locations be equipped with enclosures that are weatherproof whether or not an attachment plugs is inserted.
A. While done regularly, it is a code violation to tape the end of a 6 AWG conductor and use it as a grounded or grounding conductor. Articles 200.6(A) and 250.119(A) requires any conductor 6 AWG or smaller used as a grounded or grounding conductor to be continuous in color. But, if the wiring method is a multiconductor cable and conditions of maintenance and supervision ensure only qualified persons will service the installation, a smaller conductor may be reidentified.
Q. Is type MC cable permitted to supply lighting in a patient care exam room?
A. Maybe. If the cable sheath is listed for a fault current return path in accordance with 250.118. Type HCF (health care facility) MC cable, Type AC cable, or a metallic raceway would be required in addition to an insulated equipment grounding conductor (EGC) in order to comply with the redundant grounding requirement of 517.13(A). There is an exception in 517.13(B) that states if the light is located more than 7 1/2 ft above the floor and the switch is located outside the patient vicinity, the insulated EGC may be omitted, but the raceway or cable serving the light must still be of an approved method as mentioned in 517.13(A).