NEC Questions and Answers  - September 2006

 

 

By Mike Holt for EC&M Magazine

 

Q1. Can Table 310.15(B)(6) be used for to size the service conductors to the utility for a duplex?

A1. No. Table 310.15(B)(6) (reduced size service conductors) is only permitted for individual dwelling units of one-family, two-family, and multifamily dwellings meeting the requirements of 310.15(B)(6).

 

Q2. Can I use low voltage wiring for 24V lighting supplied by a 1.5 kVA transformer?

A2. No. All wiring must be in accordance with Chapter 3 of the NEC, unless Chapters 5 through 8 modifies the general requirements [90.3]. Since there are no rules in Chapter 5 through 8 that modify the wiring method requirements for low voltage lighting, you’ll need to use a traditional wiring method, such as Type MC cable, EMT and wire, or where permitted, Type NM cable.

 

Q3. Are there any GFCI protection requirements for a receptacle supplying a drinking water fountain?

A3. No.

 

Q4. What are the bonding requirements for a hydromassage tub pump motor if the water piping system is nonmetallic?

 

A4. None. Only metal piping systems and metal parts in contact with the circulating water are required to be bonded together, and to the pump motor [680.74].

 

Q5. Does the code require a building owner to have spare light bulbs and batteries for emergency lighting and exit signs?

A5. No.

 

Q6. How far away must nonmetallic-sheathed cable be located from metal duct work used to heat a home?

A6. No distance, however the mechanical code may have clearance requirements from water heater and/or furnace vents.

 

Q7. Can a dishwasher be hard-wired with Type NM, MC, or AC cable instead of having it cord and plug connected? 

A7. Yes.

 

Q8. Do I have to use bonding jumpers around listed reducing washers?

A8. No. According to the UL Guide Information for Electrical Equipment (White Book), listed metal reducing washers are considered suitable for grounding. This information can be found in section QCRV (Outlet Bushings and Fittings) of the UL White Book. Click here to download this document at no charge.

 

Q9. Do I need to use hospital grade receptacles in a chiropractor’s or medical examining room?

A9. No, hospital grade receptacles are not required in examining rooms, treatment rooms, clinics, and similar areas of health care facilities. However, receptacles for inpatient sleeping beds in general care areas [518.18(B); or receptacles for beds or procedure tables in a critical patient care areas [517.19(B)(2)] must be listed as “hospital grade.”

 

Q10. Am I required to have a dedicated circuit for an above the range microwave that includes a range hood if it’s cord-and-plug connected?

A10. Yes, see 422.16(B)(4)(5).