[Magnettica]

I understand that a minimum wire size of #3 or #2 aluminum would be sufficient for installation and wiring from a natural 20K generator and if so, does this apply to a 100 amp output to the switching panel before the main circuit breaker loadcenter? It is also stated that the max ampere output on this setup would only be 75amp and I need to supply the whole house circuitry which is presently a 200 amp set up. What generator size should be used and what conductor to the transfer box / load center panel which uses a 200 amp main breaker.

There's a great licensed and insured electrical contractor in your neighborhood. Contact him.

 

[jhaskins20018]

clarification

I appreciate your reply and suggestion of a licensed electrical contractor, but that's who I am. Maybe I did not word my question precisely enough. I have the ugly electrical book and have installed back up generators in the field and I know the capacities even for MCM 750, but there is a thin line on residential applications where I need to know the precise set up for using a " 20 KW " generator, natural gas feed. My client electrical house supply is a 200 amp service and he wants to have a full service supplied by this generator to engage all circuits, not just emergency designated breakers. I have the 200 amp transfer rated panel, I just need the info for the proper generator size to use and the output size wiring.

 

[Shockdoc]

Depends on your loads, CAC, electric cooking, laundry, lighting, etc. Are there gas appliances ? what is your total kw when under load ? Do the calculations or cheat , turn everything on and run an amprobe of the mains. That will predict if your 20 kw will handle the load.

 

[jhaskins20018]

Thank you

Thank you shock Doc. Your method of reasoning seems to be the best application to determine the best set up. My client has mostly all electrical appliances and the only appliance that is gas feed are his water heater, boiler for the radiators and his stove. I will use my amp probe to determine the total load with all devices on in his home which should give me both the total current draw and wattage max. Thank you again

 

[nrp3]

Don't forget that some of these transfer switches have load shedding features for AC condensers or other large loads. Depends on brand.

 

[Magnettica]

Whenever I go to determine the AWG of conductor I use ole reliable Ohm's law.

 

[captkirk]

Load shedding can only go so far....

 

[RePhase277]

Assume the generator is delivering its maximum rated watts. Size the wire based on that.