All self-service motor fuel dispensing units must be so constructed that their electrical pumping systems have an accessible switch or circuit breaker provided at a location remote from the dispensing device, including remote pumping systems, and accessible to the supervising attendant, unless an attendant is not required to be on the premises by subsection 2 of section 23-13-02.3, to shut off electrical power to the dispensing devices in the event of an emergency.