AFerguson
Electrical
- Nov 10, 2003
- 19
Multi-tenant (nine meters) warehouse, fed 240V-delta. Three customers use the 240V three-phase service, remaining customers use the 120/240V single-phase service. Three single-phase customers plan to install PV using 240V single-phase inverters.
Installation is allowed per NEC 690.63(A); however, the wording "shall not be connected to 3-phase power systems unless the interconnected system is designed so that significant unbalanced voltages cannot result" is a tough one as this is a 1980s-era building that has experienced multiple interior alterations (new install could at least have a good shot at balancing the loads, including tenants not benefiting from the PV).
Will connect the inverter outputs across the center-tapped phases, but would appreciate any input on the best way to approach the (possible) unbalanced issue.
Installation is allowed per NEC 690.63(A); however, the wording "shall not be connected to 3-phase power systems unless the interconnected system is designed so that significant unbalanced voltages cannot result" is a tough one as this is a 1980s-era building that has experienced multiple interior alterations (new install could at least have a good shot at balancing the loads, including tenants not benefiting from the PV).
Will connect the inverter outputs across the center-tapped phases, but would appreciate any input on the best way to approach the (possible) unbalanced issue.