MEC Power Group Projects

Mystic Generating Station – Tower Installation, Charlestown, MA

Owner: Exelon Generation LLC
Electrical Engineer: Stantec
Electrical Contractor: MEC Power Group

Project Scope: Installation of New Steel H-Frame 345kV Structure – MEC Power Group furnished and installed a two-pole H-frame structure to increase the ground clearance of an existing 345kV transmission line. Two 85-ft steel poles with base plates were set on concrete spread footings, with a 43-ft long W-beam cross-arm to support the existing 795 ACSR conductors and shield wires. Existing transformer taps were extended to accommodate the increased cable height. Work required the use of (2) 100-ft manlifts, a 90-Ton crane to raise the poles, and a 60-Ton crane to place the cross-arm. Work was completed during a 3-day power outage of Mystic 7 diesel turbine.

Special Electrical Challenges: All materials for the project were procured in 3 weeks (a typical procurement turn-around, as such, takes 4 to 6 weeks). MEC Power Group’s crew of six IBEW electricians, supervised by division Director Chris Lombardi, performed installations on the fast-track project in only three days in constricted work space at the fully operational power station.


Twin Rivers Technologies Co-Gen Plant, Quincy MA

Project Scope: MEC Power Group upgraded both 5kV and 15kV switchgear to support the installation of a new gas turbine at the Twin Rivers Technologies fatty acid and biodiesel manufacturing facility in Quincy, Massachusetts. The scope of work also included the installation of a new motor control center, step-down transformers, and neutral ground reactors, as well as new building power, lighting, SCADA, and fire alarm systems.

Field Crew: 15 IBEW Local 103 electricians

Special Challenges: Coordination with the owner and National Grid in order to maintain uninterrupted power to the facility’s manufacturing processes.


Exelon Mystic Generating Power Plant Maintenance, Charlestown, MA

Project Scope: MEC Power Group is providing repairs and maintenance to unit #7, a 617MW generating plant, including:

  • Outage preparation and support
  • Emergency response to issues
  • Heat trace and lighting projects
  • Breakdown test and repair of turbine generator house, station service transformer, house main transformer, precipitators, station cooling screen house
  • 12KW jet peaking unit repairs and modifications
  • Control house wiring and panel upgrades

Field Crew: 6 IBEW electricians
Project Timeline: Year-round project


Raytheon, 15kV Feeder Replacement, Andover, MA

Project Scope: MEC Power Group replaced two (2) 13.8 kV feeders, which required the installation of new 15kV metering equipment within a new cabinet, and approximately 300 linear feet of 4×5” PVC concrete-encased duct bank. Two new 15kV circuits were installed from the metering cabinet to the new 15kV selector switch. MEC also provided re-energization and testing of equipment.

Field Crew: 6 IBEW Local 103 electricians

Special Challenges: Work was required to be performed during off-hours with the use of generators to provide temporary power. The project was completed and the facility re-energized and tested within a 12-hour period.


Raytheon, LED Lighting Replacement, Andover, MA

Project Scope: As part of Raytheon’s lighting efficiency upgrades, McDonald Electrical and MEC Power Group removed 800 existing fluorescent light fixtures inside the machine shop, radome grinding room, electric rooms and boiler rooms, replacing them with new LED fixtures. New 277/480V electrical distribution panels were installed for the LED lighting system. MEC also installed new conduits, cables, and occupancy sensors to re-circuit and bring the wiring up to the present code requirements.

Special Challenges: Raytheon’s machine shop was kept operational 24 hours a day, 7 days a week during the installation and great care had to be taken by the MEC field crew to prevent tools and/or materials from falling into the machines.

Field Crew: 15 IBEW Local 103 electricians


Middleborough Gas and Electric –15kV Switchgear Replacement, Middleborough, MA

Owner: Middleborough Gas & Electric Department
GC: MEC Power Group

Project Scope: Replacement of existing 15kV indoor switchgear comprising Bus 1 and Bus 2 with a new metal-clad 15kV switchgear lineup. The project included the removal of existing switchgear and bus duct, the installation of new switchgear and bus duct, as well as replacement/installation of control cable and wiring to support the new equipment. MEC performed system testing and commissioning.

Special Challenges: Project was completed in three (3) sequential phases requiring three (3) cutovers that entailed energizing the new switchgear replacing the existing switchgear. The substation, serving the town of Middleborough, was kept operational throughout electrical construction.