Generator Transfer Switch Question

12 years ago

I recently installed a portable backup generator with a Reliance ProTran Q 510 transfer switch. Everything works great, except I had a question about how I installed it. My home has a 400 amp service with two 200 amp main panels in the house. There were some circuits in the first panel and some circuits in the second panel. The transfer switch comes with a black and red for each circuit and only one white and one green for all the circuits. I installed the green and white to their respective bus bars in the first 200 amp panel. Then I ran a conduit between the two panels and ran the red and black cables from the transfer switch to the second 200 amp panel. I did not bring over the white and green wire from the first panel to the second. The second panel was already tied to the first panel with a big copper ground wire.

So my question is: Is this legal and safe? I thought it was because the neutral and ground are bonded at the panel. And I thought the neutral/ground in one panel is the same as the neutral/ground in the other panel. All my circuits, whether on generator or main line check out with a line tester. I just want to make sure I'm not overloading the neutral and I'm not creating an unsafe situation.

Thank you for any feedback.

Thanks,

Scott

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Comments (2)

adinota3
12 years ago
No you need to bring both lines back to the secound panel and you need to keep them seperate on two different busses. The neutral (white) and the Ground wire (green) can be on the same bus in the main panel but on any sub-panel (also known as your secound panel), they must be kept seperate and the neutral bar must not be in direct contact with the panel. It usually has what looks like plastic brackets that mount to the back of the panel box keeping both the panel and the neutral bar seperate.

So it doesnt mater what kind of panel your talking about, whether you have a sub panel or main panel they must have both wires. The difference is if what you are talking about is a sub-panel you must bring both green and white lines back to the sub panel and install them on two seperate buses. *for your knowledge the main panel is the panel directly fed by your meter. Sub-panels are panels fed from another panel by a breaker or fed from a fused Main disconnect. Also if your secound panel is not fed from a breaker at the main panel and its fed directly off of the main bus from the first then it is considered a secound section of the same panel. or in your case the secound section of the main panel. But in order to be taped off from the bus on the first panel legally, both panels must be within sight of each other or else this against code.

If you need more info read more about grounding and bonding in any electrical book you can get from a barnes and noble. you might as well if your going to do that kind of work yourself. But just in case you should probably have a licenced electrician inspect the work. it should not cost much one hour at a service charge rate. Between $125.00-$150.00 (this is a NYC. rate your area might be less) not a bad idea concidering that you will at least have piece of mind its safe.

I hope this helps

-Anthony
taverty
Original Author
12 years ago
Anthony,
Thanks for the information. The second panel in my case is just another main panel. Both panels are fed by the meter not one fed by the other. They sit within 3 inches of each other and both have the thick aluminum wiring coming from the meter into the top. My meter is a 320/400 amp meter. My two main panels are 200 amp each. The neutral/ground is bonded in both main panels with a ground wire going between the two panels.

I think you're right that I should just get an electrician in to take a look. Once I have him out I'll post what he says.

Thanks,
Scott
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whoa! looks like I opened up a can of worms. Well don't worry about me pulling the meter, I'd pee my pants in the process that would add to the danger of such an act. Thanks for all of the discussions. I thought only square D had a lock out switch for their main panels and wasn't aware a lot of other companies did also. Mine is a GE 200 amp top feed. I've found a company that makes main breaker inter lock switches for many types of panels and will likely use one of them and save a lot of time, hassle, and money in the process. This will give me the desired benifit of being able to pick and choose circuits as needed only. My reasearch has lead me to more questions than answers though. I understand that the lock out switches, and most residential transfer switch panels allow the neutral and ground going back to POCO lines. Yet this situations is one of the many arguments against back feeding a breaker or the dryer outlet. Dispite that argument, these units are code approved for residential use. At least there is not the possibillity of having the main breaker on when using the genset with these devises. I guess there could be a rare situation where the main breaker is faulty or corroded enough to allow feed back into the line in the off position. The last posts dicussing floating neutrals in generators has me preplexed also. I ran across a site from a Canadian Electrician dedicated to this issue. He is advocating that you must use a floating neutral in all generators feeding a transfer switch system and actually has directions on how to accomplish this on many models of generators. According to him, most generators ship as bonded neutral models and should not be used that way for feeding a transfer switch or you risk getting shocked incertain open neutral situations, however remote they may be. I could post the web site if anyone would like. The thing the puzzles me is that there are lot of manufacturers of generators and transfer switches and none seem to address these isssues, if indeed they are valid, but they seem to be being installed by electricians and are code approved. Also, the POCO's are well aware that this is being done and not advising against it. Infact some POCO's offer service to sell, install such equipment and to maintain it. I'm sure this will stirr up a few more posts. Thanks for all the great info I gather from this site, sorry for the long post. There's another storm out there in the Atlantic, I need to get this done. Kevin
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Generator Transfer Switch Question

Comments (2)

adinota3

taverty
Original Author

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Original Author