CSA C2.2-06:2017 pdf download.Pole-mounted, single-phase distribution transformers for electricutilities
1.6 In CSA Standards, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; "may" is used to express an option or that which is permissible within the limits of the standard; and "can" is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
5.2.1 Tank grounding
A one-half inch diameter, 13 NC (1/2-13 NC) tapped hole or boss, with unpainted thread, shall be provided at the centre of the lower mounting bracket on the left side (as viewed from the low-voltage side) for tank ground connection. One bronze clamp-type terminal as shown in Figure 2(a), capable of accommodating conductor sizes ranging from No.6 to No. 2 AWG, shall be provided and secured to the transformer at the tapped hole or boss.
5.2.2.1 An external, removable, copper grounding strap shall be provided and connected to the low-voltage neutral terminal as specified in Items (a) or (b):
(a) Transformers with 1 20/240 V low voltage: the grounding strap shall be connected to X2 if either three or four low-voltage bushings are provided, but in the latter case, provision shall also be made for the strap to be connected to the X3 terminal.
(b) Transformers with 347/600Y V low voltage: the grounding strap shall be connected to the X2 terminal.The strap shall be of the size indicated in Table 6.
5.2.2.2 A single-hole, Type 304L, stainless steel spade terminal, as shown in Figure 3, shall be appropriately welded to the outside of the tank wall. It shall be at a 50 mm offset to the right from the centreline of the X2 bushing for three-bushing transformers and at the centreline between the X2 and X3 bushings for four-bushing transformers to provide unimpeded cable access to the connector of the X2 bushing. The grounding strap shall be connected to the X2 and the stainless steel terminal as shown in Figure 7(b),by means of hardware meeting the requirements of Clause 8.11 and installed to the requirements of Clause 6.2.2.CSA C2.2-06 pdf download.