MCM Engineering II, Inc products

Metal-Enclosed Switchgear: This is Switchgear that complies to ANSI C37.20.3. The construction is such that the bus is open and there are few if any barriers between the bus and cable sections. Typically the bus is not insulated, and boots are not required. This is a very cost effective construction for applications that seldom require access to the inside of the Switchgear, and for infrequent operations. Typical examples of Metal-Enclosed products are Load Interrupters, Medium Voltage MCC’s, Utility Metering Sections, pull sections, hybrid designs with LI switches in series with a Vacuum Circuit Breaker.

Metal-Clad Switchgear complies with ANSI C37.20.2: Metal Clad Switchgear is constructed with metal barriers between all bus assemblies. For example, the main cross bus is barriered off from the runbacks and risers. The upper and lower breakers are also isolated from each other, as are the cable pull sections. The most common application is for draw-out Vacuum Circuit Breakers used on installations that require the highest level of reliability. This is the kind of Switchgear seen in server farms, pharmaceutical manufacturing, or anywhere the loss of power can be catastrophic.

The MiniBreak is a small Load Interrupter Switch that is rated 4.76kv, 200A, 12.5kA symmetrical. These units are standard outdoor rated, with pull sections in the base. They can be fused up to 200E with Current Limiting Non-Disconnect fuses. Fused LI switches have a 65kA symmetrical integrated rating. Typical applications are transformer disconnects, replacement of oil switches, and utility visible disconnect switches. FYI, 200A at 4160V will get to about a 1 MVa transformer with 200E fuses (oversized by 30%). MCM Engineering II keeps stock on the MiniBreak switches. These can also be custom built in Stainless Steel or Galvaneal. The standard paint system is a 2000 hour TGIC with primer.