My suggestion
Okay, I'll throw in a few notes here.
FIRST: NEC does NOT REQUIRE a TRANSFER SWITCH.
NEC requires that the UTILITY side and an AUXILIARY source cannot be simultaniously connected.
At one time, the only method deemed acceptable by most inspectors, was to have a mechanical transfer switch.
NOW, there is a much less expensive, but very effective method: A generator backfeed interlock kit installed on your main breaker panel. This is an accessory manufactured by most panel manufacturers, and some aftermarkets- it is a UL-listed/NEC compliant device which mounts into the panel and prevents both the MAIN and GENERATOR BACKFEED breakers from being closed at the same time. I've been installing these for the last three years, recently installed one in a Square-D QO panel, the kit was $64.00 at my local Graybar store. What they DON'T do, is automatic transfer, line detection, or any other fancy stuff- strictly manual.
Next: Diesel, Gas, Propane, and Natural Gas are all viable fuels. Small generators and large generators both work fine. Three phase and single will both work. Which one you choose is totally dependant on circumstances. Here's things to keep in mind:
Air cooled generators are loud, but light. Liquid cooled are quiet, but heavy. Air cooled engines don't have coolant to freeze, liquid cooled engines tend to last longer.
3600rpm generators are usually louder than 1800 and 1200rpm generators.
Gasoline becomes varnishy, and absorbs moisture.
Diesel fuel grows algae.
Propane requires a special delivery truck
Natural gas depends on a pipeline.
EVERY TYPE of engine can sit for years without problems... but that doesn't mean they always will.
Carbeurated engines have float bowls that get cruddy, but carbs are cheap and easy to rebuild... typically have four or five moving parts total.
Gas-fueld engines (Propane and NG) have MIXERs, which are cheap, simple, and generally only have one moving part that is field-replaceable. Propane and NG doesn't get cruddy- leave propane in a bottle for 60 years, it's still propane when it comes out.
Spark-ignition engines (gasoline, kero, propane, NG) that have MAGNETOs will start without a battery. Magnetos have moving parts. Same engine with battery-coil will start nicely, but generally, an electric starter is used.
Odd-output generators are DIRT CHEAP. a liquid-cooled 15kva 240-Delta gennie will power most any home, and can be found for a couple hundred bucks. I installed a 208/125Y ex-Civil Defense unit (4-cyl Herc) in my neighbor's house for $600. With 380hrs on the clock, it was a steal.
208/125Y (Three-phase) will power a 240/120 single-phase house using two of the three hot legs and one neutral. As noted above, there'll be a little de-rate (since you're only using 2/3rds, OR you can make a third 'circuit'... but chances are not likely that you'll really 'need' that much load for a typical house.
ANY three-phase arrangement can be resolved with an appropriate application of a transformer.
When you have a power outage, consider:
What do you really NEED to operate? Don't use the electric range: use the charcoal grill. Don't use the electric dryer, hang 'em on a line. If it's wintertime, don't worry about the fridge- keep it closed, and slide it outside. Get back to the basics: well water, sump pumps, furnace.
Next- consumption.
ANY engine-driven synchronous AC generator, regardless of type or design, will require a certain 'minimum' amount of fuel just to run, even with no load. AS a load is applied, the governor will increase fuel feed to maintain proper frequency, and fuel consumption will rise. Eventually, load will increase to the point where either the generator can carry no more current, or the fuel delivery system will send in no more fuel, or the engine or generator no longer maintain thermal stability... hence, the maximum limits have been reached.
Obviously, if you can't flow any more fuel, or your fuel supply runs out, you're dead-in-the-water, so choose a fuel source you can obtain under bad circumstances. Most folks who buy gasoline or diesel-powered generators are met with serious disappointment when their stored fuel supply is depleted or no longer viable (contaminated or gelled), and the local retail stations are either out (panic buyers) or without electricity to vend. Propane delivery trucks get snowed-in, and NG lines get shut off when natural disasters rearrange the landscape. To their merit, gasoline and diesel are easy to buy and transport in 5-gallon cans. Propane is typically inexpensive, can be bulk-delivered (mine 1000 gallons at a time), and Natural Gas goes anywhere the pipeline flows. One fortunate bonus of NG, is that NG pumping stations are frequently powered by NG! Pick your poison carefully here.
If your generator unit is mil-spec, industrial-duty, etc., it will usually have an 'overload rating'... meaning, so-many-percent overload for so many hours. This is akin to 'duty cycle' on a welder- they can run continuously (and maintain proper temperature) up to a certain load level, and if you need extra, it'll tolerate it for X hours before needing to return to 'continous' load. As a result of this, you'll essentially 'never' find a bona-fide 'overload' rating on something purchased from a big-box store. Your 3000w pull-start gen has a 5000w 'surge' rating... don't expect miracles. It may survive a start-surge of 5kw, but the generator will sag tremendously while doing so. A properly rated generator will make that start with no change.
Last few notes:
Powerful generators aren't light. They're heavy.
Quiet generators aren't light. They're heavy too.
A GOOD generator, is one that accurately matches your load demand, using the best balance of fuel consumption, noise level, surge capacity, space consumption, and cost.
A BAD generator is one that is either under or over-capacity, using too much fuel consumption, too loud, unstable, too big, and too expensive.
The WORST generator, is one that won't start when you need it, uses fuel you can't get, provides insufficient power, and requires constant supervision.
So for my friends- my biggest recommendation for genuine 'emergency backup' power... if you CAN do it:
--Liquid cooled, 4-cylinder
--5-15kw capable at single-phase (either 240/120 or two of a 208/125Y)
--Gasoline, NG, or propane
--Magneto-ignition, with hand crank for emergency start
--Manual-only transfer using interlock on backfeed breaker.
--Ex Civil-Defense, public safety, or mil-spec surplus
--Start and run for at least one hour, every month.
--Size a fuel tank to hold approximately twice the amount of time which you'd expect to be without commercial utility power.
--IF liquid-fuel, use said tank to provide supply fuel for lawn equipment and your vehicles and small equipment- and add fuel to this tank on regular intervals to maintain 'freshness'.
And for those that are 'off grid'- go liquid-cooled, and remove the radiator. Instead, run the coolant into a heat-exchanger, transport this waste heat to your hydronic radiant heating system.
Thanks for the words of praise for us lowly tradesmen. I've often felt we were an under appreciated breed...
There is a reason NEMA has different plug and receptacle configurations.
Also, with a 50 amp breaker, he should be using #6 AWG wire. If an ungrounded conductor goes to ground, that #10 AWG will get very hot before tripping that 50 amp breaker.
