beanland
Senior Member
- Location
- Vancouver, WA
I find no mention in the 2008 NEC of 240/480V 3-phase 4-wire center-side grounded delta services. 100 "Voltage Nominal" mentions 120/240V, 480Y/277V amnd 600V. 100 "Voltage to Ground" mentions 208Y/120, 480Y/277, and 480V 3-phase 3-wire. The Handbook also talks about 120/240V 3-phase 4-wire delta. 220.5 mentions 120, 120/240, 208Y/120, 240, 347, 480Y/277, 480, 600Y/347 and 600V. I find no mention of 480/240V. Is 480/240V 3-phase 4-wire center-side ground permitted? Or, since it is not mentioned, it is not forbidden?