UL 467:2017 pdf free download – STANDARD FOR SAFETY Grounding and Bonding Equipment.
6.2.4 A protective-type clamp of the strap type shall have a rigid metal base to be seated on the grounding electrode, and if the clamp is designed for use with metal conduit, it shall be provided with not less than the applicable number of straps specified in Table 2, depending upon the trade size of metal conduit with which it is intended to be used.
6.3 Strap-type clamps
6.3.1 A strap-type clamp shall not be less than 12.7 mm (1/2 in) wide and 0.64 mm (0.025 in) thick.
6.3.2 A communications strap-type clamp shall not be less than 12.7 mm (1/2 in) in width and not be less than 0.64 mm (0.025 in) in thickness. Strap-type clamps intended for outdoor use shall satisfy the temperature conditioning test described in Clause 9.9.
6.3.3 Communication ground clamps may be in the form of straps of copper or other suitable metal.
6.3.4 Communication ground straps shall be fitted either with brass or galvanized steel screws.
6.4 Protection against corrosion
6.4.1 A grounding or bonding device shall be protected by a zinc coating at least 0.025 mm (0.001 in) thick, except as follows:
a) if the metal is inherently resistant to corrosion such as nonferrous or stainless steel;
b) a device that is used in conjunction with an electrical metallic raceway or metallic cable system and complies with the corrosion protection requirements for fittings in CSA C22.2 No. 18.3 or UL 514B;
C) the thickness of the coating shall be at least 0.013 mm (0.0005 in) if the device provides for a direct pressure connection between the grounding or bonding conductor and the surface of an outlet box;
d) the thickness of the coating shall be at least 0.0038 mm (0.00015 in) if the device is intended for use completely inside an outlet box.
Also see Clause 6.4.6.
6.4.2 In regards to Clause 6.4.1, corrosion protection on small parts of the grounding and bonding device, such as screws, is not specified. Evidence of corrosion protection shall be verified by visual inspection.
6.4.3 Unless a grounding or bonding device is made of a material specified in Clause 6.1.2, a plating or a coating provided on the device shall not be of a material or color that would tend to indicate that the device is of a material other than that of which it is actually made.
6.4.4 Except as specified in Clause 6.4.3, colored chromate shall be permitted.
6.4.5 Die-cast zinc or another metal shall be one or more of the following:
a) a grade or alloy known to be resistant to atmospheric corrosion;
b) subjected to appropriate tests; or
c) additionally protected against corrosion.
6.4.6 In accordance with Clause 6.4.1, a device constructed of ferrous metal shall be protected against corrosion by one of the following means or by other metallic coatings that have been found to give equivalent protection, as described in Clause 6.4.7:
a) hot-dipped, mill-galvanized sheet steel conforming with the coating designation G90 in Table I of ASTM A 653/A 653M, with not less than 40% of the zinc on any side, based on the minimum single-spot-test requirement in ASTM A 653/A 653M. The weight of zinc coating may be determined by any acceptable method; however, in case of question, the weight of coating shall be established in accordance with ASTM A 90/A 90M.