CUC utilises the 240/120Volt, 60Hz standard common in North America. CUC supplies electricity throughout Grand Cayman as alternating current (AC) at a frequency of 60Hz, and either single phase or three phase at one of the following standard voltages: 240/120 Volts, single phase, three wire, for residential and commercial service. 240/120 Volts, three phase, Edison delta, four wire for commercial and industrial service. 120/208 Volts, three phase, four wire wye, for commercial services and large apartment/condominiums complexes requiring a three phase service. 277/480 Volts, three phase, four wire wye, for large commercial and industrial services (usually not less than 300 kW). Customers should contact CUC in the planning stages of any project for approval of the service voltage, in particular three phase services, to avoid additional costs and delays. These are normal voltage classes only and the actual voltage level at the Customer's service entrance may be marginally above or below the standard voltage.