CSA C22.2 NO. 178.3:17 (R2022)

PREFACE
INTRODUCTION
1 Scope
2 General Requirements
3 Units of Measurement
4 Reference Publications
5 Definitions
CONSTRUCTION
6 General
7 Enclosure
8 Insulating Material
9 Mounting of Parts
10 Guarding and Accessibility of Live Parts
11 Current-Carrying Parts
12 Field Wiring Terminals for Control Circuits
13 Internal Wiring
14 Isolation
15 Grounding and Bonding
16 Operating Mechanism
17 Overcurrent and Ground-Fault Protection
18 Receptacles
19 Spacings
20 Wiring Space
21 Interlocking
22 Transfer Switches for Service Equipment Use - Requirements
   for All Countries
23 Service Equipment for Use in the United States
24 Service Equipment for Use in Canada
25 Transfer Switches Comprised of Circuit Breakers in Switchgear
26 Transfer Switches Comprised of Contactors
27 Transfer Switches Comprised of Load Interrupter Switches in
   Metal Enclosed Switchgear
PERFORMANCE
28 General
29 Transfer Switches Comprised of Circuit Breakers in Switchgear
30 Transfer Switches Comprised of Contactors
31 Transfer Switches Comprised of Load Interrupting Switches
   in Metal Enclosed Switchgear
32 Other Transfer Switches
33 Operations Tests
34 Overvoltage Test
35 Undervoltage Test
36 Range of Operating Voltages
37 Overload Test
38 Electrical Endurance Test
39 Temperature Test
40 Mechanical Endurance Tests
41 Dielectric Voltage-Withstand Test
42 Partial Discharge Testing Procedures
43 Dielectric Voltage-Withstand Test (Repeated)
44 Withstand Test
45 Closing Test
46 Short-Time Current Rating Test
47 Momentary Withstand Current Test
48 Dielectric Voltage-Withstand Test (Reduced Level)
49 Switching Capacity Test - Isolating Means
50 Isolating Means Interlock Integrity Test
51 Transfer Switch Operator Interlock Integrity Test
52 Impulse Voltage Withstand Tests
53 Enclosure Ground Integrity Test
RATINGS
54 Ratings
MANUFACTURING AND PRODUCTION TESTS
55 Power-Frequency Voltage Withstand Test
MARKINGS
56 Markings
57 Service Equipment Markings
58 Permanence of Marking
59 Installation Test Procedures
60 Transfer Switches for Fire Pump Service
Annex A (informative) - Standards for Components
Annex B (normative) - References
ANNEX C (normative) - Bypass Transfer Switches
ANNEX D (informative) - French Translations of Markings

These requirements cover automatic, non-automatic, and manual transfer switches, operating at voltages of greater than 1000 Vac, and intended for use in non-hazardous locations in accordance with Annex B, Item 1, the National Electrical Code, ANSI/NFPA 70, or the Canadian Electrical Code, CSA C22.1, Part 1, to provide for power as follows: a) Automatic transfer switches for use in emergency systems in: 1) Emergency systems in accordance with the Standard for Emergency Electrical Power Supply for Buildings, CSA C282-15; 2) Health care facilities in accordance with Rule 24-304 of the Canadian Electrical Code (CEC) Part I; 3) Articles 517, Health Care Facilities, and 700, Emergency Systems, of the National Electrical Code, ANSI/NFPA 70 (refer to Annex B, Item 1); and 4) The Health Care Facilities Code, ANSI/NFPA 99, (refer to Annex B, Item 12).

Preface This is the harmonized CSA Group, and ULSE standard for T ransfer Switch Equipment – Over 1000 Volts. It is the First edition of CSA C22.2 No. 178.3, and the Second edition of UL 1008A. This edition of UL 1008A supersedes the First edition titled, Medium-Voltage Transfer Switches, published on March 30, 2012. This harmonized standard has been jointly revised on May 10, 2023. For this purpose, CSA Group and ULSE are issuing revision pages dated May 10, 2023. This harmonized standard was prepared by the CSA Group and ULSE. The efforts and support of the Technical Harmonization Subcommittee, THSC 121A WG8, Transfer Switches over 750V, on the Harmonization of Electrotechnical Standards of the Nations of the Americas (CANENA), are gratefully acknowledged. This standard is considered suitable for use for conformity assessment within the stated scope of the standard. This standard was reviewed by the CSA Subcommittee on High Voltage Transfer Switches, under the jurisdiction of the CSA Technical Committee on Industrial Products (TCIP) and the CSA Strategic Steering Committee on requirements for Electrical Safety (SCORES), and has been formally approved by the CSA Technical Committee. This standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. Scope 1.1 These requirements cover automatic, non-automatic, and manual transfer switches, operating at voltages of greater than 1000 Vac, and intended for use in non-hazardous locations in accordance with Annex B, Item 1, the National Electrical Code, ANSI/NFPA 70, or the Canadian Electrical Code, CSA C22.1, Part 1, to provide for power as follows: a) Automatic transfer switches for use in emergency systems in: 1) Emergency systems in accordance with the Standard for Emergency Electrical Power Supply for Buildings, CSA C282-15; 2) Health care facilities in accordance with Rule 24-304 of the Canadian Electrical Code (CEC) Part I; 3) Articles 517, Health Care Facilities, and 700, Emergency Systems, of the National Electrical Code, ANSI/NFPA 70 (refer to Annex B, Item 1); and 4) The Health Care Facilities Code, ANSI/NFPA 99, (refer to Annex B, Item 12). Note: Transfer switches for optional standby systems are not recognized in Canada. b) Transfer switches for use in optional standby systems in accordance with Article 702 of the National Electrical Code, ANSI/NFPA 70 (refer to Annex B, Item 1). Note: Automatic transfer switches for optional standby systems are not recognized in Canada. c) In legally required standby systems in accordance with Article 701 of the National Electrical Code, ANSI/NFPA 70(refer to Annex B, Item 1). Note: Legally-required standby systems are not recognized in Canada. d) Automatic transfer switches for use in accordance with the Standard for the Installation of Stationary Pumps for Fire Protection, ANSI/NFPA 20 or the Standard for Fire Pump Controllers, CSA C22.2 No. 263, (refer to Annex B, Item 2). 1.2 These requirements cover transfer switches rated greater than 1000 V to 46 kV. 1.3 These requirements cover transfer switches together with their associated control devices including, but not limited to, voltage sensing relays, frequency sensing relays, and time delay relays. 1.4 An automatic transfer switch as covered by these requirements is a device that automatically transfers a common load from a normal supply to an alternate supply in the event of failure of the normal supply, and automatically returns the load to the normal supply when the normal supply is restored. An automatic transfer switch can be provided with a logic control circuit that inhibits automatic operation of the device from either a normal to an alternate supply, or from an alternate to a normal supply when the switch reverts to automatic operation upon loss of power to the load. 1.5 A non-automatic transfer switch as covered by these requirements is a device, operated manually by a physical action, or electrically by a remote control, for transferring a common load between a normal and alternate supply. 1.6 These requirements only cover completely enclosed transfer switches.