SWITCHGEAR BIG GRAY BOXES SWITCHBOARD

Why Different Standards? ANSI vs UL

Standards Comparison

Standards Comparison (cont.)

Switchgear has Defined Short Time Withstand Ratings! Comparison (cont.) Switchgear has Defined Short Time Withstand Ratings!

“Practice” Comparison Switchgear maintenance permitted (not required by standard). Switchboard maintenance often not allowed.

Side View

Rear View

Insulated Case vs Molded Case

Old Vs New Insulated Case UL 1066 IRON FRAME ANSI

Insulated Case vs Molded Case

Advantages of Insulated Case Vs Iron Frame Smaller footprint More reliable (Modular Design with Fewer Parts) Higher interrupting ratings Higher withstand ratings (30 Cycles) Reduced maintenance Electronic Trip Units Field Installable Trip Units Communications Power monitoring (2.5% Accuracy)

Mechanical Construction Breaker Frames Small : 800A ANSI, 1200A UL, 1600A IEC Medium : 800 to 3200A ANSI, 800 to 3000A UL, 800 to 4000A IEC Large : 4000 to 5000A ANSI, 4000 to 6000A UL, 4000 to 6300A IEC

Organic Vs Iron Frame The thermoset material of the organic case has several advantages: Very strong and lightweight Provides good insulation, isolation, and dielectric Molded to support and hold internal parts with no adjustments Fewer parts reduces complexity of assembly and maintenance

Organic Vs Iron Frame This is animated. Click the left top image to show the mech installation on the housing. The organic housing is very strong and lightweight. It provides a solid mounting base for the mechanism. Continue by clicking the top center image to show the moveable contact. The molded areas on the housing support and hold the moveable contacts with no adjustments necessary. This makes it easier to build and more reliable to use. The CTs also fit in molded supports. The organic housing provides ridgidity and a mounting area for the fixed contacts. Once the parts are installed and the housing halfs are joined together, the organic case provides good insulation, isolation and dielectric between phases and between phase and ground. The crowning touch is the patended arc chutes at are specially designed to aid in the dissipation of the heat and pressure associated with the interruption of a 200,000 Amp fault. The Organic case provides the strength, isolation, insulation, and dielectric necessary for the extremely high interrupting ratings and other features of the new Masterpact.

Display type A P H LCD ammeter LED Bargraph LCD All functions LCD

UL 891 Switchboards

Switchboards

Typical Switchboard Ratings Switchboards Typical Switchboard Ratings 5000 A Mains and Bus 1200 A and smaller group mounted Greater than 1200A Individally mounted Fixed or Drawout Front Connected UL 891 Gear UL 489 Breakers

“Hybred UL 891 Switchboards” Mix Insulated Case and Molded Case Individially mounted Front Connected Rear Connected Individually mounted Drawout Fixed Group Mounted and Drawout Fusible and Circuit Breaker No requirement for isolation or Barriers

SWITCHGEAR BIG GRAY BOXES SWITCHBOARD