Entrance of cables into boxes, cabinets, and fittings

1) Where cables pass through the walls of boxes, cabinets, or fittings, provision shall be made to

a) protect the insulation on the conductors from damage;
b) protect terminal connections from external strain;
c) provide electrical continuity between a metal box, cabinet, or fitting and conduit, armour, or metal sheathing of cables, whether or not the armour or metal sheathing is to be used as a bonding conductor;
d) prevent damage to a non-metallic sheath applied over armour or metal sheathing for protection against moisture or corrosion; and

e) close the openings through which the cables pass in such a manner that any remaining opening will not permit entrance of a test rod 6.75 mm in diameter.


2) Where insulated conductors run as open wiring enter a box, cabinet, or fitting, they shall pass through insulating bushings or be installed in raceways or insulating tubing.

3) Where non-metallic-sheathed cable or tray cable enters a box, cabinet, or fitting, a box connector, either as a separate device designed for use with such cable or as part of the box, cabinet, or fitting, shall be used to secure the cable in place adequately and without damage to the cable jacket or conductor insulation.

4) Where rigid or flexible metal conduit, electrical metallic tubing, or armoured cable enters boxes, cabinets, or fittings, it shall be secured in place in accordance with the requirements of Section 10.

5) Where metal-sheathed cables enter boxes, cabinets, or fittings, the box connector shall be installed in a manner that will meet the requirements of Section 10 without damage to the cable jacket or conductor insulation and shall be of a type for use with the cable.

6) Where liquid-tight flexible metal conduit, flexible metal conduit, armoured cable, or metal sheathed cable of a type having a non-metallic sheath over the armour or metal sheath enters a box, cabinet, or fitting, the box connector shall ensure electrical continuity without damage to the non-metallic sheath unless the point of connection is in a dry location free from corrosive atmosphere, where the non-metallic sheath shall be permitted to be stripped back a sufficient distance.

7) Where single-conductor cables or insulated single conductors enter metal boxes through separate openings, precautions shall be taken in accordance with the requirements of Rule 4-008.

Source: Rule 12-3022, CSA C22.1:21, Canadian Electrical Code, Part 1 (25th Edition), Safety Standard for Electrical Installations. © 2021 Canadian Standards Association. Please visit store.csagroup.org