Factory sealed, external seals not required, arcing is safely confined to receptacle interior|Unique blade type, brass contacts exert constant pressure along entire contact surface and provide superior electrical contact|Energized receptacle contacts deeply recessed to reduce danger of accidental touching|Insulators provide superior dielectric and mechanical strength and lowest arc tracking|ECP plug fits any standard non-explosionproof receptacle (NEMA 5-15R, 5-20R or 6-20R) as well as U-Line explosionproof receptacles|Intermateable with competitors plugs of like configurations|0.538 to 0.639 in Dia plug cable|Dead end mounting box entries|ECP plug are copper free (4/10 of 1% maximum) aluminum with epoxy powder coat|Fiberglass reinforced polyester insulating blocks