I have a Briggs and Stratton model 040301A stand-alone generator I bought used I'm trying to figure out what gauge wire I use to feed my circuit box. When I took it apart it had a black and a red wire plugged into its terminal and they were 12 gauge wire it also had a white pig tail looks like gauge 8 wire twistid to the generators red and black lead. And it has a negative ground block that you would put the ground wire in and tighten it down. This generator has a 30 amp breaker on it but it is rated for 50 amps. Is the 12 gauge wire big enough to run into my circuit box? This unit is only powering a garage that I do not have any power to I am using this generator as my power source. Please help
No, 12 AWG conductors are not large enough for 30 amperes.
Powering a structure is a complex task, which would require more details than can be provided in a short form Q&A site like this. If you need help with a small portion of this project, you might find help here. As for planning the entire project, this is not the place for that.
My advice would be to hire a local licensed Electrician, even if only for the planning part of the project.
Ok since you have no power to your garrage this is simillar to the wiring you have done, 30A takes #10 wire, but you said your system was capable of 50 so I would go to #8, make sure to bond your ground to the green wire /frame of the generator, and for added safety a ground rod would be a good idea, if you said you have a breaker pannel wire the 2 hots to the mains the ground and neutral to the respective terminals, If you ever run power to the garrage the generator will have to me removed or a transfer switch installed to prevent the generator backfeeding the service that could kill someone, and burn your generator up
Breakers protect wires from overheating. If you want to use the 12ga. wire you already have on-hand, downgrade the breaker to 20A. To keep the 30A breaker, use 10 gauge or larger wire.
If you want to future-proof and allow for 50A, then use either 8-gauge or 6-gauge depending on the wire type and environmental factors. Your electrical supply house will know more.
I know you're not asking, but if you're installing a sub-panel, think about a future in which you bring power from the house or utility service, and work to code so you don't have to rework later.
Yes a transfer switch will be the best option for you sir if you can install one just remember to follow electrical codes. And check to see if your generator needs a equipment ground and not just a service ground.
And a transfer switch that will separate the neutral from the / utility provider and the generator is also a better idea this way it will prevent any energy that was placed on the neutral from going back to the utility company and electric someone while they work on the lines
You need some 4 conductor #10 cord and a suitable plug and receptacle for 30 amps.
Here is a sample of the plug you need for most generators: http://www.amazon.com/gp/product/B000Y4FQSI?psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s01
** DANGEROUS ADVICE REMOVED **