Clyde: When you mention service neutral, are you talking about a service or are you talking about a feeder. A service has to have a neutral, see 4-022 (3). If it is a 600V feeder, 347V can (in theory) be obtained by a wye connection, but this is not acceptable to code. The star point is a neutral and has to be grounded at the service, 10-106 (1),(b) and 10-204 (1),(a).
