UL Grounding and Bonding Equipment


This category covers bonding devices, ground clamps, grounding and bonding bushings and locknuts, ground rods, armored grounding wire, protector grounding wire, grounding wedges, ground clips for securing the ground wire to an outlet box, water meter shunts, and similar equipment.

Ground Rods — Ground rods and pipe electrodes are suitable for use as grounding electrodes in accordance with NFPA 70, "National Electrical Code" (NEC), and are also suitable for use in installation of lightning protection equipment.

Ground rods are marked with rod length, and manufacturer's name and catalog number within 12 in. of the top of the rod.

Ground rod couplings are intended for connection of two ground rods and are suitable for direct burial.

Ground Clamps — Strap type ground clamps are not suitable for attachment of the grounding conductor of an interior wiring system to a grounding electrode.

Ground clamps and other connectors suitable for use where buried in earth or embedded in concrete are marked for such use. The marking may be abbreviated "DB" (for "Direct Burial").

Listed ground clamps are also suitable for telecommunication applications such as telephone, radio, CATV, and the like in accordance with Articles 800, 810, 820 and Section 250.94 of the NEC, in addition to those covered under Grounding and Bonding Equipment, Communication (KDSH).

Listed irreversible compression type connectors are suitable for splicing the grounding electrode conductor.

Clamps are intended for use with rod and/or pipe electrodes in accordance with the NEC and are marked with the size of electrode and electrode grounding conductor with which the clamp is intended to be used. Clamps suitable for use on copper water tubing are marked for such use.

Grounding and Bonding Bushings — Bonding bushings for use with rigid metal conduit are provided with means (usually one or more set screws) for reliably bonding the bushing (and the conduit on which it is threaded) to the metal equipment enclosure or box. They provide the electrical continuity required by the NEC at service equipment and for circuits rated over 250 V. Means for connecting a grounding or bonding wire are not provided and if there is need for such a conductor a grounding bushing should be used.

Grounding bushings for use with conduit fittings, tubing (EMT) fittings, threaded rigid metal and intermediate metal conduit, or unthreaded rigid metal and intermediate metal conduit have provision for the connection of a bonding or grounding wire or have means for mounting a wire connector available from the manufacturer. Such a bushing may also have means (usually one or more set screws) for reliably bonding the bushing to the metal equipment enclosure or box in the same manner that this is accomplished by a bonding bushing. Grounding bushings provide the electrical continuity required by the NEC at service equipment and for circuits rated over 250 V. They may be used with or without a bonding or grounding conductor as determined by the bonding or grounding function that is intended to be accomplished.

Insulating throat liners in grounding or bonding bushings are suitable for temperatures of 150°C if they are black or brown in color. Unless otherwise marked, insulating throat liners of any other color are suitable for temperatures of 90°C.

Grounding and Bonding Locknuts — Grounding and bonding locknuts serve in a manner similar to grounding and bonding bushings except they do not provide abrasion protection for the conductor at the end of the conduit.

Ground Mesh — The ground mesh consists of a copper wire mesh that is intended to be installed in ground or embedded in concrete and bonded to the grounding electrode system for the purpose of improving ground planes, such as an equipotential plane as described in Sections 547.2 and 547.10 of the NEC. Ground mesh is not intended to serve as a required grounding electrode as described in Article 250 of the NEC.

Protector Grounding Wires — Protector grounding conductors are intended for use in accordance with Article 800 of the NEC. They are marked with the manufacturer's name, size, and "Protector Grounding Wire."

Special Tools — Grounding connectors to be assembled to wire using a special tool are to be assembled using the tool specified by the manufacturer on or in the connector shipping carton. Such tools are identified by appropriate marking.

Some of the marking referred to above may be on a tag attached to the product.

Hospital grounding jacks and grounding cord assemblies are covered under Hospital Ground Jacks and Grounding Cord Assemblies (KEVX) under Health Care Facilities Equipment (KEVQ).

Grounding and bonding devices are for use only with copper conductors unless they are marked "AL" or "AL-CU."

For additional information, see Electrical Equipment for Use in Ordinary Locations (AALZ).

The basic standard used to investigate products in this category is UL 467, "Grounding and Bonding Equipment."

The Listing Mark of Underwriters Laboratories Inc. on the smallest unit container in which the product is packaged, on a tag securely attached to the product or container, or on the product when size or shape permits is the only method provided by UL to identify products manufactured under its Listing and Follow-Up Service. The Listing Mark for these products includes the UL symbol (as illustrated in the Introduction of this Directory) together with the word "LISTED," a control number, and one of the following product names as appropriate: "Grounding Equipment," "Bonding Equipment," "Bonding Jumper," "Ground Clamp" or other appropriate product name as shown in the individual Listings.

Joe Tedesco, NEC Consultant