Open Neutral
Senior Member
- Location
- Inside the Beltway
- Occupation
- Engineer
Large residence, with pool; fed with 400A 3ph 240/120 open delta. Solar grid tie, backup inverters, and a standby generator. We'll supply several motors with 3-ph, and house loads with 240/120v off the "lighter" winding.
I'm debating the merits of approaches on automatic transfer switches. We need both transfer from PoCo to the generator, and a manually activated emergency power off function [Big Red Button with molly-guard]. Can/should I combine these functions? It appears some ATS's are in effect "Double-throw, center off" but the spec sheets go to lengths to be incomprehensible. The alternative would be a main disconnect with a trip coil, I'd guess.
On the ATS&EPO side, it's less space, fewer things to fail. But it may well be more expensive as the ATS must be "service" rated, and be center-off.
Thoughts?
[BTW, a side issue is implementing EPO on the inverters. They have no usable control input so I'll likely have to have a trip coil in the DC breaker.]
I'm debating the merits of approaches on automatic transfer switches. We need both transfer from PoCo to the generator, and a manually activated emergency power off function [Big Red Button with molly-guard]. Can/should I combine these functions? It appears some ATS's are in effect "Double-throw, center off" but the spec sheets go to lengths to be incomprehensible. The alternative would be a main disconnect with a trip coil, I'd guess.
On the ATS&EPO side, it's less space, fewer things to fail. But it may well be more expensive as the ATS must be "service" rated, and be center-off.
Thoughts?
[BTW, a side issue is implementing EPO on the inverters. They have no usable control input so I'll likely have to have a trip coil in the DC breaker.]