UL 1653:2019 PDF Download

The UL 1653:2019 standard specifies requirements for corrugated electrical nonmetallic tubing (ENT) and mechanically-attached fittings. These products are intended to be used in accordance with various electrical codes, including the Canadian Electrical Code (CE Code), the National Electrical Code (NEC), and the Standard for Electrical Installations (NOM-001-SEDE).

The standard defines the maximum continuous operating temperature as 75°C (167°F) and the maximum ambient temperature as 50°C (122°F) for these products. Additionally, it provides guidelines for using ENT in attics, with a maximum height of 900 mm (3 ft) above the bottom of the ceiling joist and a minimum ENT material rating of 60°C (140°F). For underground installations, direct burial is permitted in Canada.

It is important to note that this standard does not apply to fittings joined by solvent cement, as those are covered by other standards such as UL 651 or CSA C22.2 No. 211.2. Similarly, fittings integral with an outlet or flush device box are covered by UL 514C or CAN/CSA-C22.2 No. 85. For products intended for use in Canada, general requirements can be found in CSA-C22.2 No. 0.