Potomac Water Filtration Plant Outdoor Substation No. 2 Replacement


Washington Suburban Sanitary Commission


Potomac, MD

Date Completed

October 2017



Potomac Filtration supplies fresh water to Montgomery & Prince George’s Counties.  Power to the pumps & equipment being fed from Substation #2 had to be maintained at all times.  Accordingly, we had to come up with a temporary power plan to maintain power for the duration of the project. This project involved the replacement of the 5kV switchgear in Outdoor Substation No. 2 and motor control centers MCC and MCB in Raw Water Pumping Station No. 1 (RWPS-1) and associated miscellaneous work. The 5kV switchgear was replaced in a specific staged construction sequence. The new switchgear is walk-in aisle type in a new weatherproof enclosure. To facilitate the replacement of the switchgear, the substation was expanded and the existing battery house was replaced. 

The two motor control centers located in RWPS-1 were consolidated into a single main-tie- main motor control center which was installed in a new electrical building adjacent to RWPS-1. The DC field excitation for raw water pumps R1 through R6 were also be replaced and included in the new electrical building. We installed new pump control panels in RWPS-1 that contain new pump and gate valve controls for miscellaneous pumps. These new DC field panels and pump controls panels were reconnected to the pumps with all new control wiring and conduit.