double pole transfer switch and GFCI

[confused11]

I am investigating having a standby generator installed to power essential circuits which will be in a sub-panel. Most residential installations use a double pole double throw transfer switch, and that is what my electrician says he does with all his installations.

Never having personally been involved with connecting two power sources before, I have a couple of questions.

I would think this creates a non-Separately Derived System (neutrals and grounds not switched), and the neutrals and grounds should then be separated in the sub-panel. It seems to me this could create problems with GFCI receptacles on branch circuits of the sub-panel when the neutral is not only tied to the generator but also back out to the utility. Has anyone had problems with this?

The other issue is when running under generator power with an imbalance between the 240 volt legs, is there not voltage on the neutral out to the electric utility?

 

[Dennis Alwon]

I am closing this thread, in accordance with the Forum rules. This Forum is intended to assist professional electricians, inspectors, engineers, and other members of the electrical industry in the performance of their job-related tasks. However, if you are not an electrician or an electrical contractor, then we are not permitted to help you perform your own electrical installation work.


If I have misjudged the situation, if for example this project is related to your work, then send me a Private Message. If you can show me that I am wrong, and that you are a licensed electrician (or at least a licensed apprentice), then I will reopen your post, and offer an apology for the delay and inconvenience.

A reminder to all members, if you see a questionable post, feel free to report it by clicking the

button at the bottom left corner of the post.