Specifications

COMPLETE REVISION
PIP ELSSG01
October 2004 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear
Process Industry Practices Page 3 of 14
• National Electrical Manufacturers Association (NEMA)
− NEMA C37.16 - Low-Voltage Power Circuit Breakers and AC Power Circuit
Protectors–Preferred Ratings, Related Requirements, and Application
Recommendations
− NEMA C37.17 - Trip Devices for AC and General Purpose DC Low-Voltage
Power Circuit Breakers
• Underwriters Laboratories (UL)
− UL 1558 - Standard for Safety Metal-Enclosed Low-Voltage Power Circuit
Breaker Switchgear
3. Definitions
purchaser: The party who awards the contract to the supplier. The purchaser may be the
owner or the owner’s authorized agent.
supplier: The party responsible for furnishing the low-voltage metal-enclosed AC power
circuit breaker switchgear
4. Requirements
4.1 Switchgear Assembly
4.1.1 The switchgear assembly shall consist of metal-enclosed freestanding
vertical steel structures containing power buses, a ground bus, low-voltage
power circuit breakers, and auxiliary control devices in accordance with the
attached purchaser’s PIP ELSSG01D Data Sheet and one-line diagram(s).
4.1.2 The switchgear shall be designed such that the breakers can be tripped and
closed and the breaker position can be viewed with the doors closed.
4.1.3 If specified on the purchaser’s PIP ELSSG01D Data Sheet, red and green
indicating lights shall be provided to indicate breaker closed and open
positions, respectively.
4.1.4 All enclosures shall be fabricated from freestanding steel frames and steel
panels, and doors shall be formed to provide a strong and rigid structure.
4.1.5 Enclosure panel and doors shall be 14-gage minimum thickness.
4.1.6 Enclosures shall be NEMA 1 unless specified otherwise on the purchaser’s
PIP ELSSG01D Data Sheet.
4.1.7 All bolted doors and removable panels shall be secured with captive slotted
fasteners or machine screws or machine bolts engaging captive nuts or
tapped holes in structural members. Self-tapping sheet metal screws shall not
be permitted.
4.1.8 Any removable panels weighing more than 50 pounds (23 kg) shall have two
lifting handles.