Steve, First check with your utility co. They all have requirements for NUG's Non Utility Generators, meaning generators not part of the utility's system. There are usually requirements to submit plans and design requirements that the utility requires. To install equipment connected to a utility without permission, could be very dangerous. Each utility has it's own rules and regulations, which you will not find in the code book. It is best to call the utility and talk to the utility inspector or engineer before buying any equipment.
Our Utility is PSE&G From: Electrical Service Installation Information & Requirements Quote: "Non Utility Generators (NUG) 4.9.1 The local Distrbution Systems Division will provide requirements to be followed by all NUG. Before major equipment is ordered and design started, a preliminary plan must be submitted by the applicant and acceptance for connection to PSE&G facilities secured."
A lot of homeowners buy these gen sets from a box store or off a truck, and assume you just hook them up, Could be a Big mistake.
Some electric utilities mandate fixed or portable generators be connected through permanently installed/permit-issued/located-at-the-buidling-servce-entrance/visible-blade/accesibe to and lockable-by-the utility/double-throw switches for manual transfer, and UL1008-labeled switches for automatic duty. These sort of kill off the “soup can”-interlocked-breaker versions. In some regions, grisly linemen deaths have led to this.
At one time in California, it was not so much as a misdemeanor to backfed utility systems with a haywired generator.
LK — Unfortunately, transformers cannot distinguish which way power travels through them, so 120/240V applied to the secondary terminals can give 12,000V or so on the primary terminals, and subsequently ‘heat up’ lines connected to that primary.
Bjarney, I hope sparky checks with his utility, they are usually glad to help you plan these installations, with good reason. We had a lineman friend that was hit with a gen hookup, while doing storm repairs. I am more than aware of the dangers involved, and I hope others, that scan these posts can benefit from them.
Thanks everyone for your input. I definitely want to know the right and safe way to install generator panels. I don't have one at present to do, but I have had to try to give a price on one for a new home owner. I have sent email to different manufacturers, about their "transfer switches", that are on the market. Obviously, somewhere either UL has overlooked something (which I know don't seem reasonable) since most of these panels are UL listed. It almost seems unreal, that all these manufactures, have products which they advertise, including some BIG, BIG, names, which I won't name, and yet they are against "the code" as I have heard explained. Something just don't seem right here. But thanks for all the input. I'm hoping I can get some clear answers soon. As far as the power companies demands, I can't even get the "electrical inspectors" demand straight right now But I really do appreciate you all's input. There's got to be an answer for the use of the "transfer switches" for portable generators, that are on the market. It may be that they have to come up with a different set up in their panels, if possible; and from a little guy like me, that is very unlikely But I have been known in the past to at least try You see, I am an small electrical contractor, and this is a part of my business, so I feel like I need to get it straight. How can I go to a customer, that wants emergency power back up from their portable generator, and explain to them that these "on the market" generator panels won't work (at least without another transfer switch that breaks the neutral, which will cost them probably another $700.00 on top of everything else.) They will think I don't know what I'm talking about, and get someone else, that don't care. It'll work out though. I guess that's the "trials of the trade". Just venting a little here Thanks again ... Steve
Just to let you know, I'm making progress on my research on portable generators that have the neutral and ground bonded together in their unit. According to the inspector in my area, this is a requirement that is necessary "not" to have to break the neutral going to the generator. I'll try to post a list for those who are interested as soon as I can. I'm still a little foggy concerning all this, but right now I'm going with what the inspector says. Steve....