NEC Article 625 Codes Quiz: Voltage and Power Supply

NEC Article 625: Electric Vehicle Charging System Equipment

• The maximum nominal AC system voltage specified in NEC Article 625 is 300 volts AC.
• Cord-connected equipment requires a nominal voltage-rated cord according to 625.17(A).

Cord Requirements

• Cords are listed for exposure to oil and damp and wet locations according to NEC Article 625.
• The ampacity requirement for the cable of cord-connected equipment is specified in Table 400.5(A)(2).
• Column 3 of Table 400.5(A)(2) specifies the ampacity for 8 AWG and larger cords.

Power Supply Cord and Interrupting Device

• The interrupting device of the personnel protection system should be located to determine the maximum overall length of the power-supply cord.
• The maximum overall length of the power-supply cord is 25 feet when the interrupting device is located within the equipment enclosure.
• When the interrupting device is not located within the equipment enclosure, the overall length requirement for the power-supply cord is 17 feet.

Locations and Conditions

• Listed cords should be suitable for exposure to damp and wet locations according to NEC Article 625.
• The highest nominal AC system voltage specified in NEC Article 625 is 300 volts AC.

Electric Vehicle Supply Equipment and Charging System

• The output cable should be suitable for exposure to oil and damp and wet locations.
• The minimum overall cord length allowed for the interrupting device of the personnel protection system is 1 foot when located at the attachment plug or within the first 12 inches of the power-supply cord.
• Flexible cable is specified for the output cable to the electric vehicle as per Table 400.4.
• The maximum overall usable length allowed for the electric vehicle supply equipment or charging system without a cable management system is 25 feet.
• The usable length of the output cable should be measured from the attachment plug to the furthest point of the cable when the electric vehicle supply equipment or charging system is not fastened in place.

Safety Requirements

• A personnel protection system against electric shock is required for supplies less than 60 volts DC.
• Each outlet installed for the purpose of charging electric vehicles should have overcurrent protection.
• Electric vehicle charging loads are considered continuous loads.
• For equipment rated more than 60 amperes or more than 150 volts to ground, the disconnecting means should be installed at a readily accessible location outside the enclosure.

Additional Requirements

• Portable equipment should be connected to premises wiring systems using a permanently installed receptacle.
• When energy cannot be back fed through the electric vehicle and the supply equipment to the premises wiring system upon loss of voltage from the utility, additional safety measures are required.
• Multiple feeder or branch circuits can supply equipment from a single electric vehicle charging system.
• The ventilation system for indoor electric vehicle charging locations should be designed to prevent the accumulation of flammable gases.
• Single-phase receptacles used for electric vehicle charging should have ground-fault circuit-interrupter protection.
• Receptacles installed in a wet location for electric vehicle charging should be in a watertight enclosure.
• The primary pad base plate should be made of a non-conductive material.
• If the charger power converter is not integral to the primary pad, it should be mounted within the primary pad enclosure or within 3 feet of the primary pad.
• The minimum enclosure rating required for the primary pad is IP67.
• The output cable should be secured to the primary pad to prevent strain relief.

Test your knowledge of NEC Article 625 codes related to system voltages and power-supply cords. This quiz covers topics such as nominal AC and DC system voltages, as well as requirements for power-supply cords and cables.