Determine the smaDetermine the smallest size THWN copper service conductor permitted for the ungrounded service conductors for a multifamily dwelling service. The calculated load for the building is 70,500 VA using a 120/240-volt, single-phase, 3-wire utility supply.llest standard size service permitted for a multifamily dwelling with a load of 95,000 volt-amperes for the line using a 120/240-volt, single-phase, 3-wire utility supply.
