Hotel receptacle location

In hotel rooms, are receptacles required to be spaced in the same dimensions as a dwelling unit? Where spacing requires a receptacle that may be behind furniture, can the distance be modified?

Section 210.60 contains requirements for guest rooms or guest suites in hotels, motels and dormitories. Where rooms in a hotel have permanent provisions for cooking, the receptacle outlets must be installed in accordance with Section 210.52, including, but not limited to, small appliance branch circuit requirements. The number of receptacle outlets in a hotel room is determined by applying Section 210.52(A) as in a dwelling unit.

In guest rooms/suites, the designer is permitted to locate receptacle outlets [minimum number determined by 210.52(A)] to align with the permanent furniture layout. At least two of the required receptacle outlets must be readily accessible. This requirement allows for a design to eliminate receptacle outlets behind a bed. When they are installed behind a bed, a guard to prevent the attachment plug from being damaged must be installed.

Preventing surges

When upgrading an old dwelling unit service, I know a surge protective device (SPD) is required. What is the minimum rating, and what type of device, in or next to the panelboard, is required?

Section 230.67 requires dwelling unit services be provided with an SPD in new installations and service replacements. The SPD may be an integral part of the service equipment, such as a device that takes the place of a two-pole circuit breaker, or it may be located immediately adjacent to the service equipment, such as an external SPD connected with an offset nipple. Type 1 and Type 2 SPDs are permitted. The minimum performance requirement for the SPD is a nominal discharge current rating of not less than 10 kA.

Mechanical protection required?

The engineer of record noted mechanical protection as required by the NEC for low-voltage wiring in a healthcare occupancy. Where low-voltage wiring is installed in an area with branch circuits from the essential electrical system, are they required to have mechanical protection in the same manner?

Requirements for mechanical protection of the essential electrical system are in Part III of Article 517. The general rule in Section 517.31(C)(3) requires mechanical protection in the form of a raceway for all life safety and critical branches. See 517.31(C)(5), which permits cables for Class 2 or Class 3 systems permitted in Article 517 Part VI, with or without raceways. Requirements for communications, signaling systems, data systems, fire alarm systems and systems less than 120V are in Part VI of Article 517.

Section 517.80 requires insulation and isolation equivalent to that provided for electrical distribution systems in patient care areas. This section clarifies that Class 2 and Class 3 signaling and communication systems circuits are not required to be enclosed in a raceway unless otherwise required in Chapter 7 or Chapter 8. Additionally, this section clarifies that the grounding requirements of 517.13 do not apply to these systems or circuits. However, Class 2 lighting circuits fed from critical or life safety branch power are required to comply with the mechanical protection requirements in 517.31.

Handhole enclosures

When installing PVC conduit underground into a handhole enclosure, do we need to drill into the enclosure and terminate in a connector? Where splices are made, can we use standard wire nuts in the handhole?

Raceways, including PVC conduit or cable assemblies listed for underground use, are not required to be mechanically connected to the enclosure; see 314.30(B). Raceways and cable assemblies are required to extend into the enclosure, not under it. Section 314.30(C) requires all conductors and any splices (including wire nuts) or terminations inside of the handhole enclosure to be listed as suitable for wet locations.

Space above a cable tray

Is there a minimum amount of space required above a cable tray installation? We have an existing installation where a new cable tray installation (due to minimum height) will end up with ducts crossing over the tray. The ducts would be 8 inches above the tray for short distances.

Section 392.18(F) requires a minimum space of 12 inches above a cable tray to ensure adequate access for installing, removing and maintaining cables, etc., in the tray. See Exception No. 4, which does permit equipment (ductwork would be included) crossing at an angle not in a straight run above the tray. Also, Exception No. 3 allows the AHJ to permit smaller distances by special permission.

EVSE receptacle size

Is it permissible to install an electric vehicle charger with full-load amps set at 32A, protected at 40A to get to 125%, using a 50A receptacle? The charger comes equipped with a 50A male cord cap.

No. See the general requirement in Section 625.44, which prohibits a 50A-rated receptacle on a 40A branch circuit.

Available fault current marking

Are panelboards now required to be marked with the available fault current at the time of installation and the value adjusted when upstream changes occur? During a rough inspection as part of a renovation, the AHJ told my foreman he would be looking for those labels.

Yes, Section 408.6 requires that switchboards, switchgear and panelboards must have a short-circuit current rating not less than the available fault current. The value of the available fault current and the date the calculation was performed must be field-marked on the enclosure at the point of supply. This requirement has been adjusted, mandating that, when modifications to the electrical installation occur that affect the available fault current, the marked value must be verified or recalculated as necessary to ensure the equipment (panelboard in this case) ratings are not less than the new value of available fault current. Where a change occurs, the required available fault current marking must be adjusted to reflect the new level.

Wiring method for pool motor

Is it required to connect a pool pump motor with a cord-and-plug connection or can we hardwire it?

The wiring to a pool motor is permitted to be hardwired where flexibility is necessary. Permitted wiring methods include liquidtight flexible metal, liquidtight flexible nonmetallic conduit and MC cable suitable for the use. Cord-and-plug connections are permitted provided the cord is no longer than 3 feet. See Section 680.21(A).

Short-circuit rating and available fault current?

At a recent code meeting, a presenter used short-circuit and fault-current values interchangeably, and I must admit I’m confused. Can you help?

A short circuit is an abnormal connection between two or more points of different potential—in other words, between circuit conductors. A ground fault is a type of short circuit that occurs between an ungrounded conductor and the normally non-current-carrying conductors (equipment grounding conductors), metal enclosures, metal raceways, metal equipment or earth. Electrical equipment is provided with a short-circuit current rating, which is the value at which the equipment is rated (can handle fault current) without sustaining damage that exceeds defined acceptance criteria.

The definition of available fault current (AFC) is the largest amount of current capable of being delivered at a point on the system during a short-circuit condition. There is an informational note figure associated with the AFC definition, which illustrates there are AFC values at the supply source (service, generator or other), the downstream distribution equipment and, ultimately, the load served. The AFC values will decrease as it travels downstream from the supply source. Electrical distribution equipment is provided with a short-circuit current rating, and the AFC is not permitted to exceed that value of current.

Overcurrent protective devices (OCPDs) have overload ratings and interrupting ratings. The overload rating is set to protect the downstream conductors and equipment. The interrupting rating is the maximum fault current an OCPD (circuit breaker or fuse) can safely interrupt. For example, a 200A molded case circuit breaker in dwelling unit service equipment has an overload rating (marked on the handle) of 200A. The interrupting rating will also be marked on the circuit breaker and may vary (for example, it may be a 10,000A or 22,000A interrupting capacity or higher).

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