Access in Drywall Ceilings, Type P Cable and More

Orange electrical cords with plugs overlaying each other | iStock / Filo
iStock / Filo

Jim Dollard has an extensive background in codes and standards. Send questions about the National Electrical Code (NEC) to Jim at codefaqs@gmail.com. Answers are based on the 2020 NEC.

Access in drywall ceilings

Are we permitted to place junction boxes for other systems above 2 x 4 lighting fixture locations in a drywall ceiling to allow access to those junction boxes? We are working in a research facility with drywall ceilings. We are trying to limit the number of locations where this will occur and do not want to pay another contractor to install access panels where junction boxes are necessary.

No, see Section 410.118. Where a luminaire is recessed in a drywall or other type of inaccessible ceiling, removal of the luminaire to access junction boxes, pull boxes, conduit bodies, etc., is not permitted. If the junction box is part of the luminaire, it is permitted. During the 2020 first draft revision stage, one technical committee added permission (314.19(C)) for such access, provided the luminaire was capable of being removed without damage and the luminaire was identified as an access point to those boxes. However, the committee with purview over luminaires took an opposite approach, which resulted in a prohibition of that practice in 2020.

Type P cable uses

It is our understanding that a new robust wiring method, Type P cable, has been added to Chapter 3 of the 2020 NEC . Are we permitted to use this cable in extremely cold environments?

Type P cable—commonly referred to as marine shipboard cable—is suitable in extremely cold environments, but it is permitted only in the venues identified in a new NEC Article 337 to address the use of this wiring method. This wiring method has been used for many years in very harsh environments that include offshore and land-based oil and gas well drilling rigs, which are frequently set up, operated, broken down and relocated. Type P cable can withstand extreme cold and heat conditions and significant vibration, and it is suitable where there is a potential for physical damage. Section 330.10 permits Type P cable to be used in industrial installations where conditions of maintenance and supervision ensure that only qualified persons will monitor or service the system. Type P cable is also permitted in hazardous locations where specifically identified in other NEC articles, for example, in Section 501.10(A)(1).

ECs’ responsibility for other trades

Is an electrical contractor responsible for extension cords used by other trades during construction where an assured equipment grounding conductor program (AEGCP) is implemented? An electrical inspector requested a copy of our AEGCP, and we provided him the opportunity to view it. He then told us we needed to continuously monitor extension cords used by other trades and repair them if necessary. Are we required to do that?

No. The requirements of 590.6(B)(2) apply to temporary wiring installations, where receptacles, other than those covered by 590.6(A)(1) through (A)(3), are used to supply temporary power to equipment used by personnel. There are two options here: GFCI protection can be provided in 590.6(B)(1) or an AEGCP can be implemented in 590.6(B)(2). In many cases, the most feasible option is the AEGCP. In the situation you describe, the EC is only responsible for the temporary power receptacle outlets they installed and any extension cords used by the EC. Individual employers in other trades must monitor the cords they use. See the informational note following 590.6(B)(2), which references OSHA standards and NFPA 70E. The implementation of an AEGCP is the responsibility of every individual employer as required by OSHA. The NEC only requires that the EC document and make available their AEGCP. The electrical inspector does not have the authority to direct an EC to implement another employer’s AEGCP.

Alphabet soup

What happened to the requirements in Article 210 for GFCI protection where appliances are involved? After reading the new 210.8(D), I need a drink and a new pair of glasses! How does text like this make the Code easier to use? This is ridiculous.

I agree there are significant problems with the application of 210.8(D). There was action taken on requirements to provide GFCI protection for appliances in Article 210 for branch circuits and Article 422 for appliances. The intent of two separate committees was to provide additional clarity and usability, so their intentions were good. However, the result is, in my opinion, a disaster. This text is not user-friendly in any manner; it is convoluted and compromises safety. In 210.8(D) there are 10 circular references to requirements in 422.5.

This text in 210.8(D) refers the  Code  user to requirements in 422.5 that require GFCI protection in an integral part of the attachment plug, within the supply cord not more than 12 inches from the attachment plug or factory installed within the appliance. This new requirement mandates (GFCI built into the appliance) that if these requirements are not met, GFCI protection must be provided within the branch-circuit overcurrent device or in a device or outlet within the supply circuit.

We relocated GFCI requirements for branch circuits into Article 422 and replaced them with circular text that can only be described as alphabet soup. There are more issues here than a simple mistake made with clarity and usability. For example, an electrical contractor bids a job and installs branch circuits. The EC does not purchase or install the appliances. How does the EC decide on the requirements of 210.8(D)? The branch circuit installation will occur long before the occupancy is finished and appliances are installed. These GFCI requirements should be mandatory in Article 210. If there is an additional GFCI in the appliance, the level of safety is increased. The  NEC  should not require the installer to gamble on whether another entity provides GFCI protection. This is not good  Code . I share your frustration and agree this needs to be revised in 2023.

Snap switch as disconnect?

In an existing facility, are snap switches used as disconnects for motors permitted? Wouldn’t a molded case switch be required?

Yes, a snap switch is permitted, provided all of the applicable rules are met. Requirements for motor disconnects are found in Part IX of Article 430. Section 430.109(C) for stationary motors rated at 2 HP or less and 300V or less, permits a snap switch as a motor disconnecting means for AC circuits only. The snap switch must be marked as suitable only for use on AC and cannot be a general-use AC/DC snap switch. The motor full-load current rating as determined in accordance with 430.6(A)(1) must not be more than 80% of the ampere rating of the switch. A molded case switch is also permitted in 430.109(A)(3).

Fire pump conductors

Where a dedicated transformer is used to supply a fire pump controller, do the rules in 240.21(C) for transformer secondary conductors apply?

No. This is a good example of where Section 90.3 applies, and Chapter 6 modifies requirements in Chapter 2. See 695.5(A), which requires that the transformer be sized at a minimum of 125% of the sum of the fire pump motor(s), pressure maintenance pump(s) motor loads and 100% of the associated fire pump accessory equipment supplied by the transformer. The primary overcurrent protection is determined in accordance with 695.5(B). It must be sized to carry, indefinitely, the sum of the locked-rotor current of the fire pump motor(s), the pressure maintenance pump motor(s) and the full-load current of the associated fire pump accessory equipment. Secondary overcurrent protection is not permitted. The secondary conductors are not required to be sized to carry locked-rotor currents indefinitely.

About the Author

Jim Dollard

Code Columnist

Jim Dollard is the safety coordinator for IBEW Local 98 in Philadelphia. He is a member of the NEC Correlating Committee, NEC CMP-10, NEC CMP-13, NFPA 70E, NFPA 90A/B and the UL Electrical Council. He can be reached at codefaqs@gmail.com.

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