Truck Stop Cable: Two Cable Rules in One Article

October 6, 2026

Article 626 is short by NEC standards, and it legislates the same cable twice.

It covers electrified truck parking spaces — the pedestals and gantries at travel plazas that let a driver shut the engine down and run the cab off shore power. Part III handles the truck; Part IV handles the transport refrigerated unit, the TRU. Each part has its own section titled "Separable Power Supply Cable Assembly," each specifies the cord in nearly identical language, and they do not say quite the same thing. The difference is where the useful part is.

One article, two cable sections

Article 626 has its own definitions

626.2 carries its own definitions, and three of them matter to a cable supplier.

Term	Definition as given in 626.2
Separable Power Supply Cable Assembly	A flexible cord or cable, including ungrounded, grounded, and equipment grounding conductors, provided with a cord connector, an attachment plug, and all other fittings, grommets, or devices installed for the purpose of delivering energy from the source of electrical supply to the truck or TRU flanged surface inlet
Cable Management System	An apparatus designed to control and organize unused lengths of cable or cord at electrified truck parking spaces
Truck Flanged Surface Inlet	The device on the truck into which the connector is inserted; considered to be part of the truck and not part of the electrified truck parking space supply equipment

The third definition repeats a boundary Article 625 also draws: the inlet sits on the vehicle’s side of the line, and everything upstream sits on the installation’s side.

The second is the one to keep. Article 625 states its 25-foot limit and its exception in terms of a "cable management system that is listed as suitable for the purpose," but Article 625 never defines the term. The definition lives here, and it is generic: any listed apparatus that controls and organizes unused cable length. A reader who wants to know what the code means by a cable management system has to leave the article that uses the phrase. That is my reading of where the definition sits, not a claim the code makes about itself.

The cable has a name, and it is not "extension cord"

626.24(A) sets the arrangement: every truck is supplied "through suitable extra-hard service cables or cords," and each connection must be made "by a single separable power supply cable assembly." One assembly per connection.

626.25 then states the prohibitions directly: "Cords with adapters and pigtail ends, extension cords, and similar items shall not be used."

No adapters, no pigtail ends, no extension cords. In a market where the field fix for a connector mismatch is a short adapter, the code has refused the whole category in advance — and it is the prohibition an installer is most likely to break, because at the point of need an adapter looks like the obvious answer. The same sentence appears in 626.32 for the TRU side, word for word.

The cord specification is the most explicit in the code

626.25(B)(2) and 626.32(B) describe the cord in almost identical terms, and it is worth reading as a specification rather than a rule.

Requirement	What 626.25(B)(2) and 626.32(B) ask for
Usage class	Extra-hard usage
Temperature rating	Not less than 90 °C (194 °F)
Voltage rating	600 volts
Location listing	Listed for both wet locations and sunlight resistance
Outer jacket resistance	Temperature extremes, oil, gasoline, ozone, abrasion, acids, and chemicals

What the cord has to be

Seven items on the jacket list. For a compound formulator that is the whole brief: fuel spills, road salt, UV, abrasion against a deck plate, battery acid and summer heat, in one product, for years, where nobody will inspect it. Set against a general-purpose flexible cord jacket, it shows how far the requirement sits from ordinary practice.

The cord is permitted "where flexibility is necessary between the electrified truck parking space supply equipment, the panel board and flanged surface inlet(s) on the truck." Both sections permit it by exception rather than requiring it — the code’s way of saying the flexible cord is what you use when a fixed wiring method will not survive being handled.

A permitted-carriage clause mirrors Article 625: other listed assemblies, "including optional hybrid communications, signal, and composite optical fiber cables, shall be permitted." A supply assembly carrying a data pair or a fiber alongside the power conductors is contemplated here too.

The 25-foot rule applies to the truck, and not to the TRU

This is the difference between the two parts, and it is the reason the article is worth writing.

626.25(B)(3) fixes the datum before it states the limit: "The exposed cord length shall be measured from the face of the attachment plug to the point of entrance to the truck or the face of the flanged surface inlet or to the point where the cord enters the truck." Then: "The overall length of the cable shall not exceed 7.5 m (25 ft) unless equipped with a cable management system that is listed as suitable for the purpose."

So the measured length is the exposed working length, not the manufactured length of the cord, and the escape route is hardware rather than a longer cable.

626.32 has no equivalent provision. The TRU section specifies the rating, the conductor count, the cord construction, the plug and the connector, and stops. No length ceiling, no cable management system exception. I am stating that as a reading of the extract rather than as a claim the code makes about itself, because the two sections are otherwise near-duplicates.

The practical meaning is not that TRU cords may be arbitrarily long. It is that the constraint written for a truck cord was not written for a TRU cord, and a supplier who assumes the two assemblies are interchangeable because the wording matches will be wrong about the length.

The conductor count and the identification rule differ

	626.25, trucks	626.32, TRUs
Phase	Single-phase	3-phase
Conductors	Three or four	Four
Identification	One conductor identified in accordance with 400.23	One conductor identified in accordance with 400.23 for use as the equipment grounding conductor
Assembly rating	20 A, 125 V or 30 A, 208Y/120 V or 125/250 V	30 A, 480 V, 3-phase or 60 A, 208 V, 3-phase
Length ceiling	7.5 m (25 ft), unless a listed cable management system	None stated
Right-angle cap orientation	Grounding member farthest from the cord	Grounding member farthest from the cord
Adapters and extension cords	Not permitted	Not permitted

Both parts require one conductor identified per 400.23, the flexible-cord article’s equipment grounding conductor identification section. The truck section says only that one conductor shall be identified that way; the TRU section adds "for use as the equipment grounding conductor."

Mind the voltage classes. 125 V and 208Y/120 V on the truck side against 480 V and 208 V three-phase on the TRU side is not one product with two connectors. A 480 V three-phase cord is a different assembly with a different insulation demand, and the shared wording of the cord clause does not make them equivalent. The receptacle rules differ too: 626.24(B) allows the truck space up to three 20-ampere 125-volt grounding receptacles, two on separate branch circuits, plus a 30-ampere three-pole four-wire single-phase receptacle; 626.31(C) gives the TRU space a 30-ampere 480-volt three-phase receptacle, or a 60-ampere 208-volt three-phase receptacle, or both. All of it sits under ground-fault circuit-interrupter protection for personnel.

The right-angle cap rule nobody expects

Both sections carry an identical sentence about the plug: it "shall be molded to or installed on the flexible cord so that it is secured tightly to the cord at the point where the cord enters the attachment plug. If a right-angle cap is used, the configuration shall be oriented so that the grounding member is farthest from the cord."

Two constraints pulling the same way: the plug must grip the cord where the cord enters it, and on a right-angle body the ground pin must be the pin furthest from the cable.

The reason is mechanical, and I give it as my reading rather than as code text. On a right-angle plug the cord exits the side of the body, so the pin nearest the cord takes the bending load when the assembly is pulled sideways, and the pin farthest away has the termination least likely to be worked loose. Putting the grounding member there makes the safety conductor the last termination to be disturbed — the same instinct as 625.9(F), which makes the grounding pole first to make and last to break on an EV coupler. Both parts also require compliance with 250.138(A).

Strain relief sits in the gantry section

The strain rule is not where you would look for it. 626.23 is titled "Overhead Gantry or Cable Management System," and its second paragraph reads:

"Means to prevent strain from being transmitted to the wiring terminals shall be provided. Permanently attached power supply cable(s) shall be provided with a means to de-energize the cable conductors and power service delivery device upon exposure to strain that could result in either cable damage or separation from the power service delivery device and exposure of live parts."

Mechanical trigger, automatic de-energization: a driver pulls away with the cord connected, and the code wants the conductors dead before the assembly comes apart. Same logic as 625.19. Note the qualifier: de-energization attaches to permanently attached supply cables, while strain relief is required without qualification.

The same section is why the supply equipment forms matter. 626.22(A) allows a pedestal, an overhead gantry, or a raised concrete pad, and which one is used decides how the cable is handled and how much of it stays exposed.

Eleven kVA a space, and a demand factor set by climate

The supply-side calculation is the part that decides whether the cable you are asked for is even the right conversation.

626.11(A) requires feeder and service load to be calculated at not less than 11 kVA per electrified truck parking space. 626.11(B) then applies a demand factor based on the climatic temperature zone, using the USDA Plant Hardiness Zone map, and the table is the interesting part.

Climatic zone (USDA)	Demand factor (%)
1	70
2a / 2b	67 / 62
3a / 3b	59 / 57
4a / 4b	55 / 51
5a / 5b	47 / 43
6a / 6b	39 / 34
7a / 7b	29 / 24
8a / 8b	21 / 20
9a / 9b	20 / 20
10a / 10b	21 / 23
11	24

The demand factor turns back up

The curve falls from 70 percent in the coldest zone to a floor of 20 percent in zones 8b through 9b, then rises again — 21, 23, 24 — in zones 10a, 10b and 11. The informational note explains it: in cold climates the heating demand is the largest load and it tracks outside temperature; in very warm climates there is no heating load and the cooling load grows instead. It is a demand factor set by a climate curve rather than an occupancy guess, and it is the clearest statement of what an electrified parking space is — a heating load with a plug on it.

626.11(D) then gives the cable supplier what they need: "Truck space branch-circuit supplied loads shall be considered to be continuous." The branch circuit is sized on a continuous-load basis, exactly as an EV charging circuit is, and not on the duty-cycle basis that governs a welding circuit. Three articles, three assumptions, each defensible for what it describes.

FAQ

Question	Answer
Can an adapter or extension cord be used on a truck stop supply cord?	No. 626.25 and 626.32 both state that "cords with adapters and pigtail ends, extension cords, and similar items shall not be used."
How long can the cord be?	On the truck side, not more than 7.5 m (25 ft) measured from the face of the attachment plug to the point where the cord enters the truck, unless a listed cable management system is used. 626.32, the TRU section, states no length limit.
What cord construction is required?	Extra-hard usage, rated not less than 90 °C (194 °F) and 600 volts, listed for both wet locations and sunlight resistance, with an outer jacket resistant to temperature extremes, oil, gasoline, ozone, abrasion, acids and chemicals.
Which pin goes next to the cord on a right-angle plug?	None that can be avoided — the grounding member must be oriented farthest from the cord.

Cable for a truck stop program

The code sets a demanding floor and leaves the real question open: what compound resists gasoline, ozone, abrasion and acid at once, and what stranding survives being coiled onto a hanger by a driver in gloves at minus twenty.

Those are the two things worth specifying and the two things a quotation usually omits. Our flexible cable range covers the extra-hard service constructions this application needs, and the compound side is treated in the jacket selection guide. Where the assembly leaves the equipment, the bend radius and strain guidance is the relevant starting point, and wet and sunlight service is covered in the outdoor cable guide. OEM and ODM projects are where a custom formulation or connector molding gets built, and our cable range is the product starting point.

Sources

NFPA 70, National Electrical Code, 2011 edition — Article 626 (Electrified Truck Parking Spaces): 626.1, 626.2, 626.3, 626.4(B), 626.10, 626.11(A) through (D) with Table 626.11(B), 626.22(A), 626.23, 626.24(A) through (D), 626.25 with (A) and (B), 626.26, 626.27, 626.30 through 626.32 with (A), (B) and (C). These are the sections the article quotes or cites. Article 400: 400.23. Article 250: 250.138(A). Article 702 and Article 705, referenced by 626.27. Public-domain copy consulted at Internet Archive, gov.law.nfpa.nec.2011.
Same edition, Article 625 (Electric Vehicle Charging System), 625.9(F), 625.17 and 625.19, cited for the comparison between the two cable rules.