CSA C2.1-06:2017 pdf download.Single-phase and three-phase liquid-filled distribution transformers
1.5 Except as specified by other CSA Standards, this Standard does not apply to auto, testing, dry-type,welding, furnace, rectifier, network, subway-type, or special-purpose transformers, or to step-voltage regulators.
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, pole-mounted transformers
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 left lower mounting bracket (as viewed from the low-voltage side) for tank ground connection. One bronze clamp-type terminal as shown in Figure 3, 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 Tank grounding, transformers other than pole-mounted
Tank grounding provision shall consist of vertical Type 304L stainless steel spade terminal(s), 50 x 90 mm minimum, with two 14 mm holes horizontally spaced on 44.5 mm centres. The minimum thickness shall be 6 mm. Transformers below 750 kV●A shall be provided with one terminal located towards the extreme right on the side of the low-voltage bushings. Transformers 750 kV●A and above shall be provided with a second terminal located diagonally opposite the first terminal.
6.3.1.3 When only one high-voltage insulated terminal is used, it shall be H1, and in such a case, the H2 end of the winding shall be electrically connected to the tank internally by a bolt-type connection. This connection shall be located in the upper part of the tank so that it is visible and accessible when the cover is removed.It shall be independent of all other connections.
A single-hole, vertical, stainless steel, spade-type terminal with a 14 mm diameter hole shall be welded to the outside of the tank wall at the location where the H2 end of the winding is connected to the tank.This terminal and the connection of the H2 end of the winding shall be positioned in the wall of the tank in the sector for the H2 bushing as specified in Figure 6 and shall be marked H2.CSA C2.1-06 pdf download.