Residential Mats operate on 120 Volt. Industrial Mats can be manufactured to operate on either 120V, 208V or 240V current. However, the 36" x 20' mat can only come in 208V, 240V since it is so large. HeatTrak often makes custom size mats for customers' specific applications. It is best to call HeatTrak with voltage questions for all custom size mats.