North America Switchgear Market, By Insulation (Air Insulated, Gas Insulated, and Others), By Installation (Indoor and Outdoor), By Voltage, (low (up to 1 kV), medium (between 1.1 kV and 40 kV), and high (above 40 kV)), By Current (Alternating current (AC) and Direct Current (DC)), By End User (Commercial, Residential, and Industrial), By Region, By Competition Forecast & Opportunities, 2018-2028F