# Transfer switch and grid tie concerns...



## JamesL (Jun 26, 2012)

Hello, I am new here so be nice. I was looking around for a solution to an issue that has presented itself. We have a couple of generators at our home that perform various tasks. One is a portable unit that we use for emergency power by disconnecting the main and using a back feed method. I also have a large st-20kw head connected to a 25hp mower engine that runs on syngas (wood gas). The other day we received notice that we are getting another rate increase (AEP VA) second in six months. So as we all know syngas will power an engine just as well as gas or diesel so I want to connect the 20kw to our home and back feed to net meter and offset that increase. Only issue is the concern of killing a lineman when the power kicks and the generator is still running. A manual transfer switch will not work because of obvious reasons. Any ideas of an automatic switch that will sever the main (grid) line and allow the generator to continue to produce power for out our then connect back to the main once the grid power is restored?


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## SonnyT (Sep 20, 2010)

There are such switch's, but I advise to have a qualified Electrician wire it up if for no other reason than to make sure you DO NOT kill a Lineman.


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## KRE (Nov 29, 2011)

A 25 hp mower engine will only produce approx 12-13KW and with your 20Kw end (assuming 4 pole) based on the average numbers I'd guess you will only get 10-11Kw. While enough to run many things in a home, that is all based on Gasoline as the fuel. When you switch to wood gas, I'd be surprised if you surpass 6-7 kw. Resip's on Wood gas engines loose much of their HP over other fuels. If your really wanting to do this, I'd suggest a engine that has at least 175 ci to start with. The more inchs the better on wood gas. You are aware that your lube oil intervals, plugs ect, will have a higher O&M cost over gasoline, LP or Natural, correct? The ATS an it's required safety package, will not be cheap either. You never said if your 20KW has a two pole or a 4 pole rotating field, that will make a big difference as to correct engine size an speed. Hope this helps, Kenneth


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## ahmedats (Jul 5, 2012)

*Automatic Transfer Switch is better*



JamesL said:


> Hello, I am new here so be nice. I was looking around for a solution to an issue that has presented itself. We have a couple of generators at our home that perform various tasks. One is a portable unit that we use for emergency power by disconnecting the main and using a back feed method. I also have a large st-20kw head connected to a 25hp mower engine that runs on syngas (wood gas). The other day we received notice that we are getting another rate increase (AEP VA) second in six months. So as we all know syngas will power an engine just as well as gas or diesel so I want to connect the 20kw to our home and back feed to net meter and offset that increase. Only issue is the concern of killing a lineman when the power kicks and the generator is still running. A manual transfer switch will not work because of obvious reasons. Any ideas of an automatic switch that will sever the main (grid) line and allow the generator to continue to produce power for out our then connect back to the main once the grid power is restored?


I think you have to use an Automatic Transfer Switch to switch between your sources of power. Following the simple steps in this article ( Wiring A Generator Transfer Switch & Distribution ...)will help you to connect your ATS yourself. Enjoy


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## KRE (Nov 29, 2011)

Transfer switch's are used to source power only. Tie breakers are used for tying two or more sources together, or to the mains. AKA Utility, Normal Power, The Buss ect. There is way more to it than just installing an closing a tie breaker.


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