Dockside Distribution Assembly, IP56, Form 4 Type 6

Overview

The Blakley team has recently been involved with a Dockside project with a requirement for a high performance, Form 4 Distribution Assembly with an incoming device rated at 800 amps.

The overall construction is in accordance with Form 4 Type 6 with segregation between all functional devices (MCCBs) and the bus bar section. In addition the load terminals for each outgoing MCCB are located in segregated sections with access to each set of terminals via a removable, transparent shield plate. All other shield plates within the assembly are also made from transparent polycarbonate.

The enclosure is double sided with access to the incoming MCCB from the front and rear. The bus bar system is located above the switchgear and has a short circuit rating of 50kA for one second. Distribution switchgear is located behind padlockable doors to the front and rear: 4 no. 400A compartments are located at the front and 5 no. 250A compartments at the rear. In addition, a separate compartment is fitted to the end of the enclosure, housing a 12 way, TP, MCB pan assembly. Segregation within the pan compartment is not Form 4 but it can be isolated locally via a 160A 4P MCCB. Each compartment has a dedicated gland plate, located at a height of 500mm above ground level. The stand has a hot dip galvanized finish.

Due to the environment at the point of installation, the enclosure is fabricated from grade 316L stainless steel and provides protection to IP56. The enclosure has a durable, painted finish, shade Dark Admiralty Grey. Thermostatically controlled anti-condensation heaters are fitted into each switchgear compartment and doors are fitted with stays, as the assembly is to be positioned in an exposed, windy location. The assembly weighs 1100kg and it incorporates a type tested, overhead lifting arrangement, which can be removed once the unit is in-situ.

All MCCBs are made by Schneider and incorporate Micrologic electronic trips, which enables long time protection to be set as low as 40% of the nominal rating.