Power-supply cord: conductors and cord material specs
NEC 626.25(B)(2) The main truck-to-panelboard supply cord must be extra-hard usage, 90°C/600V, wet- and sunlight-rated with a chemical-resistant jacket, though small 15/20 A block-heater cords can be ordinary hard service type.
Q1 NEC 626.25(B)(2) Code lookup
An electrified truck parking space installation requires flexible cord between the supply equipment, panelboard, and flanged surface inlets on the truck. This cord must be extra-hard usage, rated at least 90°C and 600 volts, listed for wet locations and sunlight resistance, with a jacket resistant to oil, gasoline, ozone, abrasion, acids, and chemicals. Which section specifies these cord requirements?
- A 626.23(B)
- B 626.25(B)(1)
- C 626.25(B)(2)
- D 626.22(A)
Show answer & explanation
Correct: C — 626.25(B)(2)
626.25(B)(2) sets the extra-hard usage flexible cord specs (90°C, 600V, wet-location and sunlight-resistant, chemical/oil/ozone-resistant jacket) for electrified truck parking spaces. 626.25(B)(1) instead governs the number and identification of conductors in the power-supply cord, not the cord's physical/rating specs.
Overhead gantry/cable management systems and strain relief
NEC 626.23(A) Electrified truck parking equipment fed by an overhead gantry or cable management system must use a permanently attached cable, and that cable must de-energize automatically if strain threatens the terminals or the plug connection.
Q2 NEC 626.23(A)
What must occur if a permanently attached power supply cable is exposed to strain that could cause cable damage or separation from the power service delivery device?
- A Strain relief is required only if the cable exceeds 50 feet in length
- B The cable must simply be labeled with a strain warning
- C The truck's onboard breaker alone is relied on to clear the fault
- D A means must de-energize the cable conductors and the power service delivery device
Show answer & explanation
Correct: D — A means must de-energize the cable conductors and the power service delivery device
626.23(B) requires a means to de-energize the cable conductors and power service delivery device upon exposure to damaging strain, in addition to mechanical strain relief protecting the wiring terminals. A warning label or reliance on the truck's own breaker does not satisfy this, and there is no length threshold in the rule.
Attachment plug and cord connector configurations by amperage
NEC 626.25(B)(4) 20-amp truck power connections use 2-pole, 3-wire 125-volt devices; 30-amp connections use 3-pole, 4-wire 208Y/120 or 125/250-volt devices — and engine block heaters get their own 15-amp exception.
Q3 NEC 626.25(B)(4)
A separable power-supply cable assembly is being connected to a 30-ampere truck flanged surface inlet. What attachment plug configuration is required?
- A 3-pole, 4-wire grounding type, rated 20 amperes, 125/250 volts
- B 2-pole, 3-wire grounding type, rated 20 amperes, 125 volts
- C 3-pole, 4-wire grounding type, rated 30 amperes, 208Y/120 volts or 125/250 volts
- D 2-pole, 3-wire grounding type, rated 15 amperes, 125 volts
Show answer & explanation
Correct: C — 3-pole, 4-wire grounding type, rated 30 amperes, 208Y/120 volts or 125/250 volts
Per 626.25(B)(4)(b), a 30-ampere truck flanged surface inlet connection requires a 3-pole, 4-wire grounding attachment plug rated 30 amperes, 208Y/120 or 125/250 volts. The 2-pole, 3-wire 20 A option is for the 20-ampere receptacle connection, and the 15 A version is reserved for engine block heaters.
TRU separable power supply cable assembly
NEC 626.32 TRU power cords must be a listed, factory-rated cable assembly from one of five approved ampere/voltage combos — no adapters, pigtails, or extension cords allowed.
Q4 NEC 626.32
An electrician wants to extend a TRU's power supply cord to reach a farther-away receptacle. What does 626.32 say about this?
- A Extension cords and similar items are not permitted
- B It is permitted only if a pigtail adapter is listed for the purpose
- C It is permitted as a temporary measure during servicing only
- D It is permitted if the extension cord is rated for wet locations
Show answer & explanation
Correct: A — Extension cords and similar items are not permitted
626.32 explicitly states that cords with adapters and pigtail ends, extension cords, and similar items shall not be used, with no exception for wet-location rating, listed pigtails, or temporary servicing.
TRU receptacle types and ratings
NEC 626.31(C) Every electrified truck parking space for TRUs needs a listed, grounding-type receptacle matching one of five specific 3-phase, 4-wire configurations.
Q5 NEC 626.31(C)
Per 626.31(C), which of the following is a required characteristic of every receptacle installed at an electrified truck parking space for TRUs?
- A It must be rated for at least 100 amperes
- B It must include an integral GFCI device
- C It must be a single-phase, 2-pole, 3-wire configuration
- D It must be listed and of the grounding type
Show answer & explanation
Correct: D — It must be listed and of the grounding type
626.31(C) requires all receptacles to be listed and of the grounding type. The section does not require single-phase configurations (all five listed options are 3-phase), does not set a 100-ampere minimum (options range from 20 A to 60 A), and does not mandate integral GFCI protection.
Climate-zone demand factors for truck parking feeders
NEC 626.11(B) Electrified truck parking feeder and service loads get demand factors from Table 626.11(B) based on climatic temperature zone — nothing else on this load may be derated.
Q6 NEC 626.11(B)
Per 626.11(B), what is the basis for selecting the demand factor used to calculate service and feeder loads for electrified truck parking spaces?
- A The connected load of the transport refrigerated units
- B The climatic temperature zone where the equipment is installed
- C The voltage class of the feeder
- D The number of parking spaces served by the feeder
Show answer & explanation
Correct: B — The climatic temperature zone where the equipment is installed
626.11(B) bases demand factors on the climatic temperature zone, referencing Table 626.11(B) and the USDA Plant Hardiness Zone map. Number of spaces, TRU load, and voltage class aren't the basis for this table's factors.
When electrified truck parking wiring must also meet hazardous-location rules
NEC 626.3(A) Electrified truck parking (ETP) wiring at vehicle repair/storage facilities or fuel dispensing stations must also satisfy Article 511 or 514, not Article 626 alone.
Q7 NEC 626.3(A)
Electrified truck parking space wiring is installed at a facility that repairs self-propelled vehicles using flammable gas for power. Which additional article governs this installation?
- A Article 514, Motor Fuel Dispensing Facilities
- B Article 511, Vehicle Repair and Storage Facilities
- C No additional article applies beyond Article 626
- D Article 625, Electric Vehicle Power Transfer System
Show answer & explanation
Correct: B — Article 511, Vehicle Repair and Storage Facilities
Per 626.3(A), ETP wiring at facilities for repair or storage of self-propelled vehicles using volatile flammable liquids or gases must comply with Article 511. Article 514 applies instead when the site is a motor fuel dispensing station, not a repair/storage facility. Article 625 covers EV charging generally but doesn't address the hazardous-location overlap this section requires.
Scope and precedence of Article 626 for electrified truck parking
NEC 626.1 Article 626 covers the external wiring that powers parked trucks and reefer units, and its rules win whenever another article conflicts.
Q8 NEC 626.1
A requirement in Article 250 conflicts with a requirement in Article 626 for an electrified truck parking installation. Which requirement applies per 626.3?
- A Neither applies until the conflict is resolved by a formal interpretation
- B Article 626, because it governs wherever it differs from other articles
- C Whichever article the authority having jurisdiction was trained under
- D Article 250, because grounding articles always take precedence
Show answer & explanation
Correct: B — Article 626, because it governs wherever it differs from other articles
626.3 states that wherever the requirements of other articles and Article 626 differ, Article 626 applies. There's no general precedence for grounding articles, and no requirement to wait on an AHJ interpretation before applying the stated rule.
Working space access and remote disconnecting means
NEC 626.22(D) Electrified truck parking supply equipment needs a clear 2 ft by 6 ft 6 in. path to reach it, plus a lockable remote disconnect that shuts down one or more sites.
Q9 NEC 626.22(D)
Under 626.22(C), what is the minimum height required for the passageway providing access to electrified truck parking space supply equipment?
- A 600 mm (2 ft)
- B 1.8 m (6 ft)
- C 2.0 m (6 ft 6 in.)
- D 2.0 m (6 ft 6 in.) only where the equipment exceeds 600 volts
Show answer & explanation
Correct: C — 2.0 m (6 ft 6 in.)
626.22(C) requires an unobstructed entrance or passageway not less than 2.0 m (6 ft 6 in.) high (and not less than 600 mm (2 ft) wide). The 600 mm figure is the width requirement, not the height, and there is no voltage-based exception in this section.
Preventing backfeed on power loss and interactive/bi-directional systems
NEC 626.26 Electrified truck parking equipment must block backfeed to the utility on power loss unless it's a listed interactive system wired under Article 702 or 705.
Q10 NEC 626.26
At an electrified truck parking space, energy back-feeding through the truck supply equipment on loss of utility voltage is:
- A Permitted only in commercial truck stops, not dwelling-adjacent lots
- B Permitted as long as the truck is equipped with an onboard inverter
- C Always prohibited with no exceptions
- D Prohibited unless permitted as an interactive system under 626.27
Show answer & explanation
Correct: D — Prohibited unless permitted as an interactive system under 626.27
626.26 blocks backfeed on loss of primary power unless permitted in 626.27, which allows it only for listed interactive systems. There's no blanket prohibition with zero exceptions, having an inverter alone doesn't satisfy the listing requirement, and the rule isn't limited by location type.
Separable power-supply cable assembly: listing and prohibited items
NEC 626.25 The cord, connector, and plug that power a truck from a flanged surface inlet must be a listed assembly — no adapters, pigtails, or extension cords allowed.
Q11 NEC 626.25
Per 626.25, what is required of the separable power-supply cable assembly used with a truck flanged surface inlet?
- A It must be field-assembled by a licensed electrician on site
- B It only needs to match the truck manufacturer's voltage, listing is optional
- C It must be a listed type, identified, and rated per 626.25(A) or (B)
- D It must be double-insulated but need not be listed
Show answer & explanation
Correct: C — It must be a listed type, identified, and rated per 626.25(A) or (B)
626.25 requires the power-supply cable assembly to be of a listed type, identified, and match one of the types and ratings in 626.25(A) and (B). Field assembly, matching voltage alone, or double-insulation without listing do not satisfy this requirement.
20-amp vs 30-amp power-supply cable assembly ratings
NEC 626.25(A)(2) The power-supply cable assembly must match its receptacle's ampere rating — 20-ampere receptacles need a 20-ampere cable, 30-ampere receptacles need a 30-ampere cable, with one narrow legacy exception.
Q12 NEC 626.25(A)(2) Code lookup
An electrified truck parking space is being installed for a sleeper-cab tractor with a 208Y/120-volt, 30-ampere receptacle. Which section specifies the rating requirement for the main power-supply cable assembly used with this receptacle?
- A 626.24(B)
- B 626.25(B)(1)
- C 626.25(A)(2)
- D 626.25(A)(1)
Show answer & explanation
Correct: C — 626.25(A)(2)
626.25(A)(2) is the specific rule requiring a listed 30-ampere main power-supply cable assembly for 30-ampere, 208Y/120-volt or 125/250-volt receptacles. 626.25(A)(1) covers the 20-ampere, 125-volt cable assembly instead, and 626.24(B) addresses the receptacle itself, not the cable assembly rating.