An electrical contractor recently requested information about the required emergency disconnects for a motor-fuel-dispensing facility. The questions related to whether the emergency power off (EPO) had to disconnect the neutral (usually the grounded conductor) in addition to all the circuit conductors feeding the dispensers and fuel pumps. Some inspection agencies require the EPO to disconnect all circuit conductors, including the neutral. Let’s take a look at the National Electrical Code’s (NEC) minimum requirements.
The general and specific requirements for motor fuel dispensing facilities are located in NEC Article 514. All of the arrangement and use provisions in 90.3 apply to motor-fuel-dispensing equipment, meaning the requirements in Chapters 1–4 apply and can be amended or modified by the rules in Chapter 5. In this case, the disconnecting means for this equipment is more restrictive. The specific circuit-disconnecting means rules are in 514.11(A), (B) and (C). This section covers two types of disconnecting means: subdivision (A) provides general disconnects for servicing and maintenance operations, while (B) addresses emergency controls for attended fueling facilities, and (C) covers emergency controls for unattended fueling facilities.
Section 514.11(A) provides the general requirements for circuit disconnects that are other than emergency controls. The rule indicates that all power circuits leading to or through dispensing equipment must be provided with a means to simultaneously disconnect all circuit conductors, including the grounded conductor(s) if used in the circuit. The disconnect action must also simultaneously remove all associated power, communications, data and video circuits, and equipment for remote-pumping systems. This means a disconnect is required to be provided with a clearly identified and readily accessible switch or other approved means, located remote from the dispensers. Single-pole breakers using handle ties shall not be permitted to accomplish the simultaneous disconnecting required in this section. The subdivision (A) requirements call for disconnecting all power-circuit conductors, including any neutral that is part of the circuit. These requirements differ from the emergency control requirements in subdivisions (B) and (C).
Emergency controls attended
The NEC requirements for emergency controls for motor-fuel-dispensing equipment installed in attended fueling facilities are located in 514.11(B). These requirements are derived from NFPA 30A: 6.7.1 and are included in the NEC as extracted material. For attended fuel stations, the emergency controls are required to meet the provisions in 514.11(A) and must be at a location acceptable to the inspecting jurisdiction and not more than 100 feet from the dispensing equipment. This disconnect is for emergency purposes, and this emergency control is to stop all fuel from being pumped and dispensed when necessary. If there is a fire, the emergency controls will stop fueling the fire.
Emergency controls unattended
The NEC requirements for emergency controls for motor-fuel-dispensing equipment installed in unattended fueling facilities are located in 514.11(B) and are a bit different, but the same objectives apply. Note that these emergency control requirements for unattended fueling facilities are derived from NFPA 30A: 6.7.2 and are included in the NEC as extracted material. For attended fuel stations, the emergency controls are required to meet the provisions in 514.11(A) and must be at a location acceptable to the inspecting jurisdiction: not less than 20 feet from the dispensers and not more than 100 feet from the dispensing equipment. If there is a fire, the emergency controls stop fueling the fire and are located at least 20 feet from the dispensing equipment. Anyone having to quickly disconnect the fuel pumping operation in an emergency is most likely the customer pumping the fuel. The disconnect locations of this section require the customer to leave the area of the dispensing operation to activate the emergency disconnect. These controls must disconnect all power to the dispensing equipment and shall be reset by manual means in a manner acceptable to the authority having jurisdiction.
In summary, NEC 514.11(B) and (C) cover the emergency controls for motor-fuel-dispensing equipment. If one branch circuit supplies a single motor fuel dispenser, a single disconnect switch can often satisfy the requirements of 517.11. For multiple dispenser installations, meeting the shutdown requirements means more control and equipment. To accomplish the simultaneous disconnecting of all dispensing equipment in emergencies, installers often use a single EPO button interconnected to panelboards equipped with either shunt-trip main breakers or a power-actuated relay for simultaneously disconnecting all power circuits for the dispenser equipment and associated systems such as communications, video and data circuits. As 514.11(A) indicates, all circuit conductors, including any grounded (neutral) conductors, must be opened by the disconnecting means and emergency controls addressed in this section.