Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Send questions to firstname.lastname@example.org. Answers are based on the 2017 NEC.
Marking requirements for industrial control panels
When is an enclosure considered an industrial control panel? We have always applied Article 409’s marking requirements to enclosures that contain both power and control. One installation we’re working on has a dozen or more enclosures with only control devices inside. Do we need to mark those enclosures as Article 409 requires?
Yes, the marking requirements of 409.110 will apply to each assembly with two or more components of a power circuit, control circuit or a combination of both. Article 100 defines the term “industrial control panel.” An enclosure with a single component such as a single motor controller, overload relay, push button, or timer would not be considered an industrial control panel because there is only a single component. Where two components of a power circuit or control circuit or a combination of the two exist, the enclosure is an industrial control panel.
The requirements of 409.110 state each of these enclosures must be marked with the manufacturer’s name or trademark and the supply voltage, number of phases, frequency and full load current for each supply circuit. Where more than one electrical source exists and more than one disconnecting means is required to disconnect circuits at 50 volts (V) or more, the marking must indicate more than one disconnecting means must be opened to de-energize the equipment. The disconnect locations must be documented and available.
The easiest way to meet this requirement is to label the location of the all disconnecting means on the industrial control panel. Marking the short-circuit current ratings is required for all enclosures except those containing only control circuit components.
As the facilities manager for a small campus, I received a risk manager’s report that included damage to electrical systems. The damage referred to in this report is multiple conduits that were dented. Together with our electricians, we determined there was not an issue and the minor dents were not of concern. To support our position, we referenced an informational note in 300.4 of the 2017 NEC that stated minor damage to a raceway does not necessarily violate the integrity of the contained conductors. The risk manager’s response explained the informational note was not part of the NEC and we needed to replace those conduits. Does the NEC address this issue? Do we need to replace those conduits?
The informational note to 300.4 in the 2017 NEC that references minor damage was added in error and corrected by errata 70-17-1 on Sept. 29, 2016. Each NEC cycle, multiple issues occur during revision that get corrected as an errata or through the tentative interim amendment (TIA) process. In many cases, the Code-making panels realize an error occurred or a conflict/correlation issue exists due to a revision, and the TIA process is implemented to correct the issue. In this case, the second revision to add this informational note failed to get two-thirds of the vote on the written ballot. The negative votes included concern on the inability to see inside a raceway or cable assembly to determine if damage had occurred.
Additionally, the term “minor damage” would be open to a very wide range of interpretations. For example, in this scenario, the risk manager believes the damage seen is a serious concern while the electricians determined it was not an issue. The owner, together with those qualified and perhaps the authority having jurisdiction, must make these determinations on a case-by-case basis. All NEC users should be aware that NFPA lists errata and TIAs for each NEC cycle on its website. There are only a few errata and TIAs each cycle. However, they may have a significant impact on your installation. They are easy to locate and download for your records.
GFCI, swimming pools
Can we provide GFCI protection for swimming pool branch circuits by installing a GFCI-protected circuit breaker that feeds a small load center? An inspector recently failed one of these jobs and required each branch circuit to be the GFCI type, in spite of the fact that Article 215 permits it.
Section 215.9 provides general permission for a feeder to be GFCI protected where it supplies 15- and 20-ampere (A) receptacle branch circuits requiring GFCI protection. This permission is limited to the branch circuits supplying receptacles . This section prescriptively identifies this GFCI protection “in lieu of” that required in 210.8 and 590.6, but there is no reference to Article 680. Multiple requirements in 680 simply require GFCI protection, which could be provided by the feeder overcurrent protective device. However, hardwired motors or luminaires, for example, would require a GFCI in the branch circuit.
See also 680.23(A)(3), which prescriptively requires GFCI protection to be installed in the branch circuit that supplies luminaires operating on voltage greater than the low-voltage contact limit.
Labeling power cables?
Would you kindly guide me to the regulatory references that would apply to labeling power cables? I need to explain why I recommend to our infrastructure team that they need to properly label power and data cables. I see some potential hazard issues that need to be remedied. Our facility deals with cybersecurity, and we need to take every step possible to ensure continued operation.
The NEC does not contain a general requirement to label service, feeder and branch circuit conductors. Section 110.22(A) requires each disconnecting means to be legibly marked to indicate its purpose unless it is located and arranged so that the purpose of the disconnect is evident. The Code contains general requirements to identify ungrounded conductors by phase and system as well as identifying grounded and equipment grounding conductors. However, these requirements apply to individual conductors and not raceways or cable assemblies. One example of specific system marking requirements is in 690.31(G)(3) for PV system DC circuit conductors.
OSHA requirements for electrical distribution systems in the general industry standard (1910) are based upon the NEC. See Article 708, Critical Operations Power Systems (COPS). This article and the necessity for such COPS apply only where the facility owner chooses to implement these rules or where it is mandated by municipal, state and federal (or other) codes by any governmental agency having jurisdiction or by facility engineering documentation.
Per Article 708, where a COPS is installed in a building with another electrical power system, all boxes, enclosures and receptacles in which COPS are present must be permanently marked so they will be readily identified as such. However, Article 708 does not contain a requirement to identify service, feeder or branch circuit conductors.
It is important to understand all NEC requirements are minimum requirements only; compliance with the NEC is the least you can do . The fact that there is not a specific requirement to label all raceways and cable assemblies does not mean it is not a good idea in your facility. Article 708 references NFPA 1600 2013, Standard on Disaster/Emergency Management and Business Continuity Programs ; NFPA 110, Standard for Emergency and Standby Power Systems; and NFPA 730 2014, Guide for Premises Security .
Verify equipment grounding at county fair?
For the past four years, we have been installing the temporary power for the county fair, which is held locally. There was a minor shock incident due to the owner’s faulty equipment last year. Starting next year, we have been informed by the county that we must provide documentation of the equipment grounding for all portable electrical equipment. Is this an assured equipment grounding conductor program (AEGCP)? Is this an NEC requirement?
The wiring installed for power and lighting at a carnival, circus, fair or similar event falls under the scope of Article 525 and is considered as “portable wiring.” Article 590, Temporary Installations, contains requirements for temporary power and light.
Article 525 does not require an AEGCP to be implemented. However, 525.32 requires the continuity of the equipment grounding conductors (EGCs) to be verified each time portable electrical equipment is connected. While this section does not require the verification of the continuity of the EGCs to be documented, in this case, the owner requires the documentation.
STOW cord in cable tray?
Is STOW cord permitted in cable tray? This is a hard service cord that is rated for both damp and wet locations. Our intent is to run this cord in the cable tray and transition in a junction box to MC cable to supply equipment.
No, STOW cord is not permitted to be installed in cable tray. See Section and Table 392.10(A) for permitted wiring methods in cable tray.
Flexible cords and flexible cables must be installed in accordance with Article 400. Flexible cord and flexible cable are not permitted to be used as a substitute for the fixed wiring of a structure unless it is specifically permitted in 400.10 and there are no provisions permitting flexible cord or cable in cable tray.