UL 635 PDF

1 Scope

1.1 This Standard covers insulating bushings and accessories for insulating bushings used for the following purposes in electrical equipment:

1. a) Insulating bushings used for the protection of cables, flexible cords, and insulated wires, where routed through internal or external walls of electrical equipment.
2. b) Insulating bushings used to provide strain-relief for flexible cord and single conductor insulated wiring and to protect such cords or wiring.
3. c) Accessories to insulating bushings used to supplement the characteristics of the bushing.

1.2 This Standard does not cover bushings used in the following applications:

1. a) Bushings for the protection of uninsulated conductors.
2. b) Strain-relief insulating bushings used to hold more than one cable, wire, or cord.
3. c) Bushings that are an integral part of a flexible cord.
4. d) Bushings used at the end of a raceway at the point of connection to open wiring and bushings used in conjunction with rigid or flexible conduit, conduit fittings, electrical metallic tubing, armored cable, or non-metallic sheathed cable.
5. e) Bushings for power circuit breakers, transformers, or similar power apparatus rated more than 600 volts.
6. f) Bushings intended for outdoor use.
7. g) Bushings used on armored cable between the conductors and the outer armor.
8. h) Insulating bushings provided either separately or as part of a conduit fitting.
9. i) Rainproof or liquid tight bushings.
10. j) Bushings for use on the ends of rigid or flexible conduit.
11. k) Closures of the type used to plug holes in outlet boxes or outlet box covers:
    1. 1) Covered by the Standard for Metallic Outlet Boxes, UL 514A and by the Standard for Nonmetallic Outlet Boxes, Flush-Device Boxes, and Covers, UL 514C; or
    2. 2) Of the type used to plug holes in enclosures.
12. l) The following items covered by the Standard for Conduit, Tubing, and Cable Fittings, UL 514B:
    1. 1) Cord grips;
    2. 2) Insulating bushings;
    3. 3) Liquid-tight flexible cord fittings;
    4. 4) Mesh grips;
    5. 5) Strain relief grips;
    6. 6) Strain relief grips for bus drop cables;
    7. 7) Strain relief grips for flexible cords; and
    8. 8) Strain relief with wire mesh cord grips.

1.3 In this standard, a requirement which applies to one type of bushing is to be identified by a specific reference in that requirement to the type of bushing involved. In the absence of such specific reference or when the general terms “bushing” or “insulating bushing” are used, it is to be understood that the requirement applies to all other types of bushings covered by this standard.

Summary of Topics

This reaffirmation of ANSI/UL 635 dated April 24, 2025 is being issued to update the title page to reflect the most recent designation as a Reaffirmed American National Standard (ANS). No technical changes have been made.