If I were to get one, and I have been thinking about it.. I'd shoot for diesel for endurance and and the realities of the day I would need it, as it just might be a quake of 6.+ NG would be cut-off in different parts of the city just due to ruptures.
So Joe, you own one, would the breaker in it be one that you stock or would install? I've seen some I would give a second thought about seeing them on landscape lighting. Do you think it will operate in the tested 60hz 120'240 paramiters at ~30hz @ 60 volts? The fact that the safeties that are installed (Over-load, and under-freq) dropped the load before the breaker reaction time to me is pretty telling. Over-load protection circuits are there for protection of the engine, not the wiring or load the gennie is supplying. And some generators offer a by-pass button for that.... Under-freq is kind of a dual protection circuit that protects certain loads and offers some over-load and shortcircuit protection, because in those situations the windings slow down and even stop, but mainly for power quality. Depending on the circuit they may actually be the same 'over-load/under-freq' because the would act the same in effect. A loss in engine RPM.
I used to start 50HP motors with 60Kw generators (not that you would ever do that at home, but as an example) and it would temparalily stall the engine for a moment. From 60 to 10Hz due to in-rush current. The generator would physicaly shutter. This also drops the voltage for anything else on circuit... But do that on a 100Kw set, and you barely notice...
That proposed 702.5, for ATS would allow 2 options, full load, or load managment. Load management can be done in a number of ways, and still not exclude you from running the whole house as a connected load - just a managed load... A home like yours (Which has about 3X the load of mine at 1300sq') is a much smaller load than what I see install a 1/2 mile away from me in richer areas of town. Where as you could max yours out at 100+% and have to try to do it. Some of the homes I wire would stall a generator of that size - easy. Like dropping the clutch in your truck. But the diffence if that it doesn't just damage the engine, it creates other voltage and current problems on all the circuits connected to it. (Depending on the winding and regulator design.) A frequency controlled design would then just pump more fuel to compansate the loss in RPM/Hz - if it can... The reason they often wont auto-by-pass or reconnect is because this can be a dangerous electrical fault, and the idea not to self-destruct of cause damage. Would you connect to an under-voltage, 35Hz source? Or purposely over-load a transformer, or phase convertor? A generator is no different - IMO it has nothing to do with manufactures or thier bottom line. A generator is nothing more than a rotating transformer - in your case, a 12Kw transformer with an engine primary.
Really these types of residential units are kind of new in the grand sceme. I think the code is just playing catch up to the consumer protections and Darwin Award winning homeowners, but left some leeway for those facilities that still have qualified humans to operate these machines in reasonable methods, as opposed to the auto-connecting switch....
