Back up Generator question

I just purchased a used Generac 8500w peak, 5500w continous rated at 30 amps. It is 120/240 equiupped. My question is, on my old 1000w generator which was 120v, I made a double male ended cord, and after tripping the main breaker and anything 240v that might come on, I plugged the generator into an outlet in the garage and it gave me the necesities for the short term. I only was able to power one side of the bus bar, but being 1000w it was about enough.
I want to hook the new generator up to run the house on the 240v. I am considering making up a double male cord also for this one of #10 wire. I have a 240v welder outlet in the garage, I guess you could call it a dryer type outlet. 3 prongs on a 6/2 cable. The generator has a recetpicle for a 4 pronged plug. Is there a satisfactory way to make this work, going from 4 prongs to 3. I know I can physically make it work, by gyping things, but I am looking at the big picture here for a longer term. Could there be grounding issues that could damage the generator? Would it be better to buy a 4 prong outlet to match the generator's, and attach it seperately to the breaker box? The old generator was only used maybe, 3 times a year for a few hours use each time. And it was never a permanent hookup, as the new one won't be either. I wanted to get around buying a transfer switch box for such limited use.

Is your Generac properly grounded? (like say a 3/8 copper bar driven 3' into the dirt, connected to generator ground by 6-10ga solid CU wire?)?

If so, then I wouldn't worry about the 4 prong (personally) cord, essentially all it adds is a specific conductor to ground seperate from the neutral leg (on the off chance one of your appliances fail catastrophically). If you either haven't, or don't plan to permanently ground (or have a grounding bar installed near the hook in spot, ready to attach to the gene. when you do use it) the generator properly, I would def go for the four prong conductor (wire) because during normal ops you'll never have a problem, but in a failure situation, you might overload the single conductor returning to the generator.

wouldn't just be easier to have a electrician wire up a couple 240 volt outlets in the house and the garage. what do you need 240 for. where are you located.

GB,

I'd buy a 4 pole Receptacle and Plug, change your Welder over to the 4 Pole, and change out the old 3 pole receptacle for a 4 pole.

Then when your power went out, it would be a simple plug in after cutting the mains off.
Sort of an "upgrade" !

Of course grounding the system would be advisable as Navar says.

Do you have an Alarm for notice of restoration of Normal Power?

Have a good Day !
S.W.

Thank you all for your responses.
As a response to one question, I need 240v to power my pump, hot water heater, and range. Idealy not all on at the same time. Which I could not previously do. I do not have a commercial power restore alarm light. I either stopped periodically and checked, or if at night, looked to see if the neighbor's lights came back on. I live in a rural area. I have a ground rod at the rear of the garage the utilities are grounded to. I guess this would suffice.
Correct me if I am wrong. If I ground the generator to the utility ground rod. I guess I could use a jumper cable for my car for the temp hookup. Hook a 4 prong recepticle to the breaker box, using #10 wire or larger for the outlet and extension cord, I should be good to go.

I would think that would be fine... buuut, Personally I would use 8ga or 6ga CU as opposed to 10ga because at peak you are exceeding the max current capacity for that wire (say for example (admittedly worst case) you peak load on one side of the bus - you are looking at putting 8500 watts (or ~71 amps @ 120v) through a single conductor, -- maximum allowable ampacity of 10ga is 30-40amps (range depends on temp/type)... the ten GA would be fine if your 8500w load were spread evenly over a 240v circuit, but any 120v load (since it's pulling off of one side) is going to unbalance the load one way or the other.

Of course as an alternative to 8/6GA, you could do double 10ga conductors on each leg (admittedly a guerilla solution, but as long as the wire is the same size, you can double the current capacity safely...)

If I lived alone, I wouldn't worry about all that, I'm capable of balancing my loads,... but I've got three kids and a wife-- their power demand is... unpredictable... an I wouldn't want to figure out there was a problem when the cable started smoking!

BTW - I was gonna suggest a jumper cable to run to the ground rod, but I forgot... Quick and easy...

As for the alarm, i just spiked in a light/switch to the mains *Danger! Will Robinson! Danger!*(not for the faint of heart, or the stupid as doing it wrong 'll kill ya! ) ... Of course I can't see my neighbors without some driving... that's a much easier solution if you can see the neighbors!

Thank you Navar, I do live alone so load balancing is less of a problem. I will try to get 8ga cable for the outlet and extension cord from gen running to outlet.

I just finished the project. I got an owners manual by email from the mfg. Factory current draw on the 240V outlet is rated @ 23 amps max. So I purchased 25 feet of 10/4 electrical cord to connect the generator to the outlet, 3 feet of 10/3 with grd to connect the outlet to breaker, two 30 amp male plugs for each end of the cord. One 30 amp outlet, box and cover plate, and lastly a 30 amp ITE breaker for the panel. Total cost of $125. I hooked everything up, and tested it and it works. Bring on the storms!