QO® Circuit Breaker Load Centers, PK18GTA, from Square D® are Underwriters Laboratories (UL) Listed and CSA rated panelboards. They are designed to meet residential, commercial, and industrial requirements to protect electrical systems, equipment, and people. All metering stacks are shipped from the factory with meter sockets and vertical bus bars pre-installed, and require a minimum of on site labour to install the circuit breakers and main bus links. Screw-on, sealable covers over the meter sockets and circuit breakers are finished with a grey epoxy powder coating. Provision to lock and seal the circuit breaker handles in the ?off? position has been made for the convenience of utilities and electrical inspectors. This 247/600V and 3 phases unit is avaible with 500A vertical bus bar. 3-pole Powerpact H-frame circuit breakers are required for the 125A, 7- jaw sub-service sections and are available from 60A-125A. The unit comes in sizes of height 79.62 in, 15.33 in width and 6.5 in of depth. All meter stacks are designed for CSA Type A ?cold metering? in which the individual sub-service breakers are connected on the line side of the meter sockets thereby protecting the meter and all electrical equipment installed subsequent to it.