Since 1967, MCG has manufacturers Surge Protectors devices for use on AC power lines from the damaging and disrupting effects of lightning and utility switching overvoltage transients. MCG AC protectors are used in many large industrial and commercial sites to protect critical computer and microprocessor based equipment at the site entry as well as deep within the site at the equipment itself. 120VAC to 600VAC, 1,3 phase, delta, wye, high leg.