UL 1008A:2ED 2017-09

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 Circu
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
electric 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

The revision of ANSI/UL 1008A dated April 30, 2020 includes the following changes in requirements: – Clarification of required frequencies for tests; 33.1.1, 37.4, 41.1, 44.5, 47.2.1, 47.2.3, 49.3, 54.3 – Correction to electrical endurance requirements; Table 7

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).