Electrical Reference Library · Technical Reference

Tray Cable (TC and TC-ER)

Tray cable (Type TC) is a factory-assembled multiconductor cable with an overall jacket, built for cable tray and other industrial raceway uses. This sheet explains the TC and TC-ER markings, common constructions and where each may be used.

Ref EL-0010NEC 336UL 1277

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

Type TC is power and control tray cable covered by NEC Article 336 and listed to UL 1277. It has two or more insulated conductors under a nonmetallic jacket, with or without a grounding conductor. It is used in cable tray, raceways and outdoor locations supported by messenger, and in other places Article 336 permits. TC-ER (exposed run) cable has passed added crush and impact tests. That lets it leave the tray and run exposed to equipment under the conditions in 336.10, usually in industrial establishments where only qualified persons service the installation.

How to identify

Read the print legend on the jacket. It shows the type letters, conductor count and size, insulation type, voltage rating and any added ratings such as sunlight resistant or direct burial. Power tray cable usually has a few larger conductors plus a ground. Control tray cable has many small conductors, often color coded by an ICEA method or printed with numbers. Check the legend and spec sheet for the color code.

Jacket marking decoder

Marking	Meaning	Notes
TC	Tray cable	Base type under NEC 336 and UL 1277
TC-ER	Tray cable, exposed run	Passed crush and impact tests; exposed runs limited by 336.10
TC-ER-JP	Exposed run, joist pull	Added testing for pulling through framing where 336.10 permits
TC-ER-HL	Exposed run, hazardous locations	For hazardous location uses where Chapter 5 permits
Sunlight resistant	Jacket is UV rated	Needed for outdoor exposed runs
Direct burial	Rated for burial without raceway	Must be marked; check burial rules in Article 300
LS	Limited smoke	Optional rating for certain spaces
Shielded	Overall or pair shields	Common on instrument and VFD cable

Key points

The conductor insulation type, such as THHN/THWN-2 or XHHW-2, sets the conductor ratings. Read it from the legend.
Ampacity comes from NEC 336.80 and the referenced tables. Do not estimate it.
Without the ER marking, TC cable must stay in tray, raceway or other supported methods Article 336 allows.
VFD tray cable is a special construction with symmetrical grounds and shields. It is not just TC with a different color.
Many TC cables are also listed as other types. Read the whole legend before quoting uses.

Common mistakes

Running plain TC exposed from the tray to a motor.
Ordering control cable by conductor count without confirming the color code method.
Using indoor-only cable for an outdoor exposed run.
Treating the jacket rating as permission to use the cable as building wire in dwellings.

Governing standards: NEC Article 336 (power and control tray cable); UL 1277 (electrical power and control tray cables). The adopted NEC edition and the cable spec sheet.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

More in Technical Reference

← All Electrical sheets