NEC 626 covers details related to the provision of electrical conductors & electrical equipment in electrified truck parking spaces. These parking spaces are to be provided with the external power supply system (offboard power supply) supplying power to truck onboard systems such as refrigeration, air conditioning, heating, and other appliance loads associated with trucks thereby eliminating diesel engine idling.
NEC 626.4(A) clarifies that Article 626 does not cover power supply systems & electrical equipment associated with residential, commercial, and industrial facilities used for loading & unloading cargo and operating conveyors on the site or truck. NEC 626.4(B) specifies that a.c system voltages used in the power supply for Article 626 (Electrified Truck Parking Spaces) are rated generally rated at 120, 120/240, 208Y/120, or 480Y/277 nominal.
NEC 626.10 requires that branch circuits supplying power to truck parking spaces shall be derived from 208Y/120 V, 3 phase, 4 wire system or from 120/240 V, single phase, 3 wire system. In the case of existing electrified truck parking spaces, branch circuits deriving power from a 120 V distribution system are permitted.
NEC 626.11(A) requires that the total calculated from the feeder or service shall not be less than the athematic sum of loads that are associated with total branch circuits. A minimum 11 kVA electrical load shall be considered for each electrified parking truck space shall be considered while calculating electrical service or feeder circuits. NEC 626.11(B) requires that a demand factor as per Table 626.11(B) shall be considered while carrying out load calculations for feeders and services. These demand factors are based on the climatic temperature zones. No other demand factors other than the above shall be considered while calculating the loads. NEC 626.11(C) requires that for carrying load calculations associated with two or more electrified truck parking spaces, equipment for each truck parking space shall comply with NEC 626.11(A) as covered above. Branch circuit loads associated with electrified truck parking spaces shall be considered to be continuous for sizing purposes.
NEC 626.22 covers wiring methods and material requirements for electrified truck parking space supply equipment. NEC 626.22(A) requires that supply equipment shall be provided on a pedestal or overhead gantry or raised concrete pad. NEC 626.22(B) requires that the supply equipment shall be provided at an elevation not less than 600 mm (2 ft) from the ground or highest water level mark in case of a pedestal or raised concrete pad type. NEC 626.22(C) requires that the supply equipment for electrified truck parking space shall have unobstructed access to the entrance or passageway clearances of not less than 600mm (2 ft) wide and 2 mts (6 ft 6 in.) height. NEC 626.22(D) requires a common disconnecting switch or circuit breaker shall be provided at a remote location for operation for disconnecting one or more supply electrified truck parking space supply equipment sites. This disconnecting means (switch or circuit breaker) shall be located in a readily accessible location and it has the ability to lock in an open position.
NEC 626.23 covers details about overhead gantry or cable management systems in electrified truck parking spaces. NEC 626.23(A) requires that electrified truck parking space electric equipment shall be provided with a permanently installed power supply cable in case equipment is provided from the cable management system or from an overhead gantry. Other cable types such as hybrid communication, signal, and optical fiber cables if listed for the suitable purpose shall be permitted. In case of any strain exposure on the permanently installed power supply cable supplying power to electrified truck parking spaces equipment, means shall be provided for de-energizing the cable & the power supply delivery device shall be provided. This is to be done in order to avoid any cable damage and exposure of live parts due to strain.
NEC 626.24 covers details related to electrified truck parking space supply equipment connection means. NEC 626.24(A) requires that each truck is provided with power supply equipment through appropriate extra hard service cables or cords. Each power supply equipment connection shall be considered as a separate power supply cable assembly. NEC 626.24(B) requires that all the receptacles connecting to supply equipment are of the grounding type. Each parking truck is required to be provided with three receptacles. Each receptacle is of a 2-pole, 3-wire grounded type and rated for 20 A, 125 V. Two out of these three receptacles are connected to two separate branch circuits. Also each parking truck can be provided with one single receptacle. This receptacle is of 3-pole, 4-wire grounded type and rated for 30 A with voltage rated for 208Y/120V or 125/250V. In case electric supply equipment provides power supply for heating, air conditioning, and comfort cooling functions instead of requiring to have a direct electrical connection at the truck, two receptacles (as identified given in NEC 624.24(B)(1) shall be required. NEC 626.24(C) supply equipment shall be provided with disconnecting means (disconnecting switch or circuit breaker). This disconnecting means shall be located in a readily accessible location and shall have the ability for locking in an open position. NEC 626.24(D) requires that all the receptacle outlets are to be provided with ground fault circuit interruption protection for the personnel.