Quote Originally Posted by electrofelon View Post
Yeah certainly if an inverter does actually put current on the neutral, I wouldnt advocate for connecting it to the EGC. I also wouldnt really care for smaller inverters on smaller systems where the wire length is usually short and the conductor not very big. However, IMO, 480 string inverters (or central inverters for that matter) should be designed to not require a neutral. IT makes a big difference in labor and materials.
The topology the inverter uses can have an impact on complexity and efficiency. If they use 480V inverter modules in a delta rig then they need 480*1.414 = 679Vdc available into the inverters, not a problem in 1.5kV arrays but easy to fall below in 1kV arrays. If the PV array voltage falls below that then it has to be boosted up and that adds a new circuit and new losses into the system, so more cost and less competitive inverter. Same 480V inverter with 277V inverter modules connected in a WYE only needs 392Vdc and in a 1kV PV array that usually means no boost stage is needed. Everything is a tradeoff.