All metal underground water pipes

Recently, we had a service upgrade inspection where the AHJ required we bond the incoming water for the sprinkler system. He was upset that we did not bond the rebar in the concrete, but let it go. We had the domestic water bonded. Is all that required?

All metal underground water pipe(s) must be part of the grounding electrode system (GES). This question is about items recognized as grounding electrodes and minimum requirements for the GES. See Part III of Article 250. Section 250.50 requires all grounding electrodes described in 250.52(A)(1) through (A)(7) present at each building or structure to be bonded together to form the GES. This means that all metal underground water pipe, along with all other electrodes listed in 250.52(A), must be part of the GES.

There is an exception for concrete-­encased electrodes (rebar) of existing buildings. Where the rebar is not accessible without disturbing the concrete (often the case), it is not required to be part of the GES.

The connection to the metal underground water pipe cannot rely on water meters or filtering devices and similar equipment. Where the metal underground water pipe is used for a sprinkler system, the connection must be located before any flexible fittings, commonly referred to as victaulic fittings.

A metal underground water pipe must be supplemented by an additional electrode [250.53(D)(2)]. This can be one of the others listed in 250.52(A). Where the supplemental electrode is a ground rod, 250.53(A)(2) applies. This requires another electrode, which is typically a second ground rod. Section 250.53(A)(3) requires the ground rods be spaced a minimum of 6 feet apart. Additional spacing increases the efficiency of the ground rods.

Receptacle in a cabinet

Where the design in a dwelling unit bathroom has mirrors down to the countertop, is it permitted to place the required receptacle inside the cabinet? It is the only way I can get one within 3 feet of the outside edge of both sinks without cutting the mirror.

No. See the parent text in 210.52, which affects all the required receptacle outlets in this section. All the receptacles required by 210.52 must be in addition to any receptacle part of a luminaire or appliance, controlled by a listed wall-mounted control device, located within cabinets/cupboards or located more than 5½ feet above the floor.

Against the wall?

Is it permitted to place a switchboard with the back 6 inches from a block wall? Is there a concern with heat?

There is no concern with heat buildup; see Section 408.18(B), which requires clearances around switchboards and switchgear to comply with 110.26. Where all connections and renewable or adjustable parts of the switchboard, such as fuses or switches, are accessible from locations other than the back or sides, working space is not required. Note that where rear access is required to work on nonelectrical parts on the back of the switchboard, a working space of 30 inches is required.

Outside branch circuit requirements

We installed a 208/120V, 600A outside feeder to supply a new annex at a school. The owner’s representative noted that a 20A receptacle from a source other than the building’s feeder-supplied panelboard (600A circuit breaker) had to be installed within 25 feet of the feeder-supplied equipment, as per 210.63. Is that correct? Do we need to run a single branch circuit to the new building for a receptacle?

Section 210.63 has been modified significantly over the last few NEC revision cycles. The general requirement is to ensure that all equipment requiring servicing has a 125V, 15A or 20A receptacle outlet installed at an accessible location within 25 feet of the equipment.

The concern noted in your question is seen in the revisions to 210.63(B)(2). This requirement now addresses all indoor equipment requiring dedicated equipment space, as seen in 110.26(E), including all service equipment, switchboards, switchgear, panelboards and motor control centers. The requirement in 210.63(B)(2) mandates that the required receptacle not be connected to the load side of the equipment’s disconnecting means—in this case, a 600A circuit breaker. The technical committee recognized this issue with respect to service equipment and added text to omit service equipment from this requirement. Your question is about an outside feeder-supplied panelboard in a separate building.

The 2020 NEC text clearly stated on the load side of the equipment’s branch circuit disconnecting means; it was revised in 2023 to include feeders as well. While the present text requires the receptacle not be connected to the load side of the 600A panelboard disconnecting means in your question, a second feeder could be installed in compliance with 225.30(B). However, I do not believe that is the intent of this rule. There is a need for clarity in a future revision cycle. This is an example of where the AHJ can exercise special permission, as seen in Section 90.4.

Multiple emergency disconnects

Do we need to interconnect multiple emergency disconnects at a gas station? Additionally, does the neutral get disconnected, too?

Yes, the requirements of 514.11(A) mandate that when more than one emergency shutoff device or electrical disconnect is provided, all devices must be interconnected. The emergency disconnects must be located not less than 20 feet, and no more than 100 feet, from the fuel-­dispensing devices they serve. The emergency disconnect is required to simultaneously disconnect all conductors of the circuits, including the grounded conductor (neutral), from the source of supply. The emergency disconnect must remove power to all dispensing devices; to all remote pumps serving the dispensing devices; to all associated power, control and signal circuits; and to all other electrical equipment in the hazardous (classified) locations surrounding the fuel-dispensing devices.

Panelboard in stairway?

The NEC states that a panelboard can be installed on a stairway landing. A plan reviewer informed us that is not permitted. Can you help?

The requirement you referenced is in 240.24(F), which prohibits overcurrent protective devices from being located over the steps of a stairway. This requirement is permissive in nature, allowing a panelboard, for example, to be installed on a stairway landing. In small two-level apartments/condominiums, there is limited space, and the landing is used in many cases. It is important to note that the installation of a panelboard in an egress stairway (governed by the Life Safety Code) is not permitted. See Section 300.25, which addresses stair towers and other exit enclosures such as an egress corridor. In those spaces, only electrical wiring and equipment necessary for egress, etc., are permitted.

Secured in the ’on’ position

Does the Code require a device to lock a circuit breaker in the closed position for a fire alarm system?

No, the NEC permits the disconnect for the power supply to be secured in the “on” position. See Section 760.41(A) for non-power-­limited fire alarm circuits and 760.121(B) for power-limited fire alarm circuits. Both requirements mandate that the disconnect for the power source be identified with red markings and accessible only to qualified personnel. The disconnects must also be labeled as “FIRE ALARM CIRCUIT.” The red markings are not permitted to be placed over, damage or obscure the manufacturer’s markings. Branch circuits supplying fire alarm systems are not permitted to be GFCI- or AFCI-protected.

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