Transfer switch or cutoff switch?

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I recently bought a Coleman Powermate Genny. It's 7000 watts, 875 surge. While I'd love to backfeed my main panel for convience reasons I do realize it's illegal and unsafe. I'm considering a double pole 20 amp cutoff switch before the meter. (The main line is buried, comes u to the meter and exits behind the meter to the main panel inside th house). The main panel is a Cutler-Hammer 200 amp box. I don't se where an interlock switch(at the main breaker) is available for my box Would a double pole cutoff switch make it safe to backfeed? I have 120/240 30amp plug on the genny and already have an existing 50am socket on the wall for my compressor. Can I backfeed the 30amp lin thru the 50amp socket? If backfeeding can't be accomplished, I'd consider a manual transfe switch if I could find the right switch for my application. Most are u to 7500 watts but I don't know if that will be enough with the surg capability of my genny
-- rh45 ----------------------------------------------------------------------- rh455's Profile: http://www.homeplot.com/member.php?userid=2 View this thread: http://www.homeplot.com/showthread.php?tV39
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CH and others offer panels that will do the job for you. Home Depot used to sell them. I am unaware of a CH made switch to tie the main and your genny feed breaker together. Not that they do not make one now I just have never seen one.
I know what double pole switch is, and that will not solve the problem for you. A double pole double throw switch MIGHT. Depending on the installation. I suggest you consider a 3 pole and not tie the neutrals from the utility and the genny together.
Back feeding in any form is not a good idea. I doubt strongly that your 50 amp outlet is set up for 4 wires. IF it is 4 wire then...................
All you need is a 60 amp switch. 8750 divided by 240 is 36+ amps.
Best bet is call a pro in your area and have them inspect the situation and give you pointers on what exactly needs to be done per your local codes and authorities.
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Check this link out http://www.generlink.com/about_generlink.cfm

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That's cool. I never knew anything like that existed. I'll call my powe co. to see if it's available here. I'll probably call Generlink to ge more info about the unit. Seems almost too simple. I'm wondering wha the inside of the unit looks like and how it assures not backfeedin the utility pole
-- rh45 ----------------------------------------------------------------------- rh455's Profile: http://www.homeplot.com/member.php?userid=2 View this thread: http://www.homeplot.com/showthread.php?tV39
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rh455 wrote:

Just sounds like a small semi-auto transfer switch w/ a relay sensing the generator output to open the line-feed breaker. The site is almost useless for any <real> content, but it does say it it is a disconnect when you close your internal breaker to supply the feed from the genset.
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Your double pole switch will not be adequate, though it will work. The requirement is for a switch that will prevent both line and generator to be connected at the same time. The DPST switch will allow you to do that, but it will also allow you to forget to do it. Someone suggested a DPDT switch. That would work if there is an intermediate position in which neither is connected, or else you have the same problem. And, unless it is UL listed for that application it still will not meet code.
You might want to confirm this by emailing the manufacturer, but I don't see a problem with your generator on a 7500w transfer switch. They have circuit breakers in them, like what is in your breaker box. Your breakers don't trip everytime you turn a motor on, does it? So I don't see why the transfer switch should trip in a comparable situation. But it is easy enough to check with the manufacturer.
The generlink someone recommended looks like a pretty neat solution; except installation might be expensive. Just don't forget that you still have only 7000w, even though every circuit in the house is hooked to it!
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rh455 wrote:
> I recently bought a Coleman Powermate Genny. It's 7000 watts, 8750 > surge. While I'd love to backfeed my main panel for convience reasons, > I do realize it's illegal and unsafe. I'm considering a double pole 200 > amp cutoff switch before the meter. (The main line is buried, comes up > to the meter and exits behind the meter to the main panel inside the > house). The main panel is a Cutler-Hammer 200 amp box. I don't see > where an interlock switch(at the main breaker) is available for my box. > Would a double pole cutoff switch make it safe to backfeed? I have a > 120/240 30amp plug on the genny and already have an existing 50amp > socket on the wall for my compressor. Can I backfeed the 30amp line > thru the 50amp socket? > If backfeeding can't be accomplished, I'd consider a manual transfer > switch if I could find the right switch for my application. Most are up > to 7500 watts but I don't know if that will be enough with the surge > capability of my genny. > >
To comply with the US National Electric Code the connection arrangement for your generator must be immune from human error. That means it must be impossible to connect the generator to the public power lines even by accident. Since it is physically possible to connect the generator to the house with that double pole switch closed it is unlawful to connect it that way. Additionally double male plugs are known as suicide cords for a reason. One mistake means that you or a loved one could die. Do it right or don't do it. The least expensive way to connect a generator to the entire house would be to install a new SquareD feed through panel ahead of your existing panel and install the SquareD interlock kit in it. The cost of the equipment will be Two Hundred Fifty dollars ($250). You would have to rearrange your existing panel to separate the neutrals and Equipment Grounding Conductors (EGCs) onto separate buss bars and isolate the neutral buss from ground. That new panel can be tied in anywhere between the meter and the existing panel but if you use an exterior panel you gain a place to supply outdoor equipment, branch circuits, and feeders. The equipment could include well pumps, air conditioners, pool equipment, jacuzzis, or fish ponds. The branch circuits and feeders would be those serving separate buildings or the loads I just listed. A two hundred ampere transfer switch, on the other hand, would not give you any of those advantages and would cost $340 for the indoor version of just the switch itself.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
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You can hurt yourself on anything, and suicide cords are easier than many; but are they really that dangerous?
If you opened your main breaker first, wouldn't it be perfectly safe to plug into the backfeed outlet first and then into the generator? (yes, I know that if you forget to open the main breaker it is potentially live...)
And if you foolishly plugged into the generator first it still wouldn't be all that dangerous. Touching the hot alone would do nothing since the generator is not grounded (and hopefully the genny has a GFCI anyhow). To be hurt it would be necessary to touch both hot and neutral. While that would hurt, unless it was on the chest (a difficult thing to achieve) it wouldn't be particularly dangerous.
I know 10 people will jump on this and tell me that everyone know they are really dangerous and I am fool to be questioning it; but HOW are they really dangerous?
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toller wrote:

You are assuming that you are the only one that will try to use it and that you will never be drunk, over tired, stressed out, or otherwise impaired when you need it. Can you guarantee that it will never be hooked up by some helpful neighbor or no it all teenager while you are at work or out of town?
I have worked in fire and rescue since 1981. In those thirty years I have attended about five serious electrical injuries. Of the two electrocutions I can recall one was a cheater cord to bypass the safety on an appliance during trouble shooting and one was a suicide cord that was used to re energize wiring rendered dead by an open in the wiring. As you might have guessed the decedent was a child of five years of age.
The International Brotherhood of Electrical Workers is committed to seeking manslaughter charges against anyone who causes the death of an outside wireman by back feeding. Feeling Lucky? -- Tom Horne, Inside Wireman, IBEW#D841733
--
Tom Horne


Well we aren\'t no thin blue heroes and yet we aren\'t no blackguards to.
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Dumbass! Touching the hot alone would give you a shock, potentially a fatal one, because the generator *is* grounded -- what do you think it's sitting on, anyway?

Wrong AGAIN. Will you PLEASE stop giving electrical advice? You're DANGEROUS.

Because you can get a fatal shock if you touch either of the hot prongs.
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Regards,
Doug Miller (alphageek at milmac dot com)
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Maybe I misunderstood the directions I was given. I was told to turn off ALL breakers, then the main. Connect the cable to the generator, then the wall socket. Crank the generator and let it warm up then turn on only the breakers needed but keeping in mind not to overload the capacity of the generator. I didn't see the risk of shock while the main is off and the generator is off. I don't profess to be an electrician by a long shot. I was thinking that a double or triple pole master cutoff switch before the meter would make it impossible to backfeed the utility pole. Is this wrong? I was told that the main breaker may not have sufficient gap to ensure the electricity won't "jump" the gap in the main breaker, but a safety cutoff switch has several inches of clearance between the two.
Tom, I like the idea you have about the Square D box, but it does seem like a lot of work. I see Square D sells a 200 amp breaker box with the interlock switch already in it. Would this replace the box I have now? I almost bought one recently, but didn't know enough about it. My neighbor has a big master cutoff switch box outside next to the meter. It's to cutoff power before it gets into the house to the main breaker. That's where I got the idea. I really don't want a transfer switch/box but I'm still weighing the pros/cons. I just think it's so much easier and so much more flexiblity.
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rh455
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up a checklist and really checked it as done. Assuming you follow the checklist, the main danger is that the main breaker could be defective and not really open. Sure, you would probably just stall the generator as it tries to power your neighborhood, but linemen have been electrocuted this way, so it is a serious possibility.
And, as Tom points out in his reply to a post just above, you could be doing it when you are tired or drunk and get it wrong, or somebody else could do it and screw up. Besides, it is illegal, and supposedly the utility will check houses with lights on; though I expect that is an urban legend.
I bit the bullet and installed a transfer switch a year ago. I haven't had an opportunity to really use it (knock on wood...), but I feel better about it as it is pretty foolproof.
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If I install a manual transfer switch, should I get a 50 amp switch t be safe since most 50amp switches are rated to 12500 watts? Is i possible to connect a 30 amp plug (on generator) to a 50 amp switch Maybe if it's hardwired to the switch
-- rh45 ----------------------------------------------------------------------- rh455's Profile: http://www.homeplot.com/member.php?userid=2 View this thread: http://www.homeplot.com/showthread.php?tV39
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Check out these interlock kits for Cutler-Hammer Panels: http://www.interlockkit.com/cuthamr0.html

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Excellent info John. I looked high and low and couldn't find an interlock kit on CH's website. It looks like just a lockout plate and decals in the kit. Isn't there two breakers in an interlock kit? One for the utility power and one for the genny? If I do the interlock kit, will I need another 30amp 240 breaker and wire it to another plug box to connect the generator to?
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rh455
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I think that these interlock kits utilize the existing main breaker and one new 2 pole circuit breaker for the generator input. The two pole generator circuit breaker will need to be located just below the main breaker in the existing electrical panel. This insures that when the panel main is closed the genny main is open. Shutting off the panel main will allow the genny main to be turned on which in turn blocks the panel main from being flipped back on.

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The way mine works is, you remove the branch wire from the breaker and connect to the box, which goes to the Common of a dpdt switch. The NC of that switch goes to the regular breaker, so normally everything works as before. The NO goes to the generator. Flip the switch and power come from the generator instead of the power company. Thus, there is no possible way to ever switch the generator output to the power company wiring. Barring severe damage, it's foolproof. I have 12 ckts on mine; that's plenty to run everything I might need in an emergency situation. Oh, it's also got an overcurrent breaker in case too muich power's drawn, as does the generator also. Nothing but breakers, so it's a pretty simple design. There's also a current meter for each leg of the incoming split phase power so you can see how balanced the thing is on your generator. It's convenient for testing periodically too, since you just flip on the switches you need to create your load. It's not even necessary to touch the main breaker. Transfer switches make lots of sense. The more expensive ones will even start the generator for you, and switch everything over, automatically. But I ain't that rich & don't mind flipping a switch & pushing a button to start the generator.
Pop
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John, in doing some research I found that the biggest fear of most is that the main breaker may fail while in the off position thus still allowing power flow as if it were still on. I suppose that this cenario is still possible with an interlock kit. Is this right?
Pop, I don't have either switch at the moment, but don't I have to do both of the steps you listed regardless of which switch I get? With a cutoff, I go outside, throw the cutoff and lock it down. Then connect the generator and turn on the circuits that I want. With a transfer switch, I have to turn the main switch on the transfer switch from utility to generator, connect the generator and select the circuits that I want to run. Did I miss something? Aren't I doing the same steps regardless of what switch I choose?
Another problem I'm facing is that the breaker box in my house is in a confined area, barely wider than the box itself. I won't have any place in the immediate area to install the transfer switch. From all ads I've seen, the harness is only about 2'. The wall that the breaker box backs up to is the breakfast area, so Wifey won't be thrilled about that. Any ideas?
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rh455
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Comment inline :===>
message

===> Not addressed to me, but ... I have to wonder how a mains breaker could "fail" while it's in the off position. Some of them take a man and a boy just to set them on. What would be the "failure" mechanism they are worried about? I can't see a Mains breaker either turning ON spontaneously, or mechanically failing so it can't be turned back on, being much of a worry. The biggest "danger" in my opinion, is always that the wrong person might discover the breaker and flip it from ignorance, or a child playing in there, neither of which should be easy to do. "Should" being the operative word.

===> I think that depends on your local codes, not my descrip; please read on.
With a

===> OK, that totally disconnects the entire house, which is practical and totally acceptable. Now nothing can go into the power lines as long as the switch was the right type and design. So, I agree.
Then connect

===> The generator is always connected. In my (and most others I know of) case, the generator can be left plugged in. The only caveat is that, by code here at least, there must be a "quick disconnect" provided for the generator. That's so the power company, police, fire, etc. can quickly disconnect power if there is a generator running. So I was told, anyway. My generator isn't literally connected all the time though, per sae. I often load it onto a trailer to haul around for the occasional job where I need poertable power. It's only an 8,000 watt generator (surge, I forget the steady run wattage at the moment). In the summer it's not connected since it's so seldom needed. Soon's the winter weather comes though, I put it in its little compartment, plug it in, fuel it etc, and plug it in for the duration. So, I may or may not have to plug it in. To use it, I just roll it out of its little "house", push the start button, and let 'er rip soon's it's warmed up a bit. But, point is, if your setup were good enough, you'd never even have to disconnect it. Its output isn't connected to anything because of the transfer switch.
With a transfer

===> No. There is no Mains switch other than the breakers on the generator.
connect the generator and select the circuits

===> Yes, you would have to do that. My transfer switch has 8 ckts, one of which is a 220V pair for the well pump (we're rural). The other 6 go for furnace, fridge, two for lights, one for the bedroom outlets, and the last one to the basement lighting. If I need to run the pump periodically I have to be sure the fridge and furnace aren't running, but that's an acceptable situation for me since I can't afford a bigger generator. It takes the pump about two minutes or so to build up the pressure tank and then I turn it off; that's plenty for occasional drinking water and a couple of toilet flushes, plus it protects the water heater. It's only REAL intent is to keep the house from freezing and lit up for saftey/protection. The rest is just gravy so that we can stay here if the power goes out for an extended period of time, which has happened twice since we got it, the worst being in '98.
Did I miss something? Aren't I doing the same steps

===> Sort of, but no, not quite. I apologize for breaking up your paras like that, but I thought it might be easier than trying to dispute or agree to things that might interact. I don't consider the "number" of actions as important as I do the simplicity and reliability of the actions to be taken. eg, it doesn't matter whether the generator is plugged in or not. My transfer switch has no mains breaker; just "replacement" breakers to my breakre box for the generator to use. The "switches" in the transfer switch are actually individual breakers. You cannot use them like you would alight switch, but they are designed to be turned on and off without becoming damaged as the breakers in your box might do.

===> True, the harness is short and best installed next to your breaker/fuse box. But, when you get into the instructions, you'll find I think, instructions to extend it, including the wire gage and current capacities, wire lengths, etc. for extension. So, that harness can be extended. My location isn't as cramped as yours, but I still chose to add about 6 feet to the harness. I used a box with clampdowns to splice the wires, and ran them up to the breaker box thru another piece of metal conduit. Actually, since the transfer switch wiring (in my case at least) consists of stranded wire in that harness, it's my opinion that they assume you'll extend it. If you've ever worked with stranded wire that size, you'll know what I mean <g>! I extended it with appropriately sized solid wire.
I forget whether it's "emergen" (no quotes) or something close to that, but try googling on that and see if you don't come across a transfer switch web site. If that doesn't work, come back and ask me for the web site. I'd just give it now, but I'm disabled and at the moment it would be sort of a hardship to get out there to find it. Aha! Found it:
http://www.nbmc.com/images/emergenistall.jpg
And the web site entry is at: http://www.nbmc.com/emergen/index.html
They give a pretty good description that might help with understanding what i'm talking about.
One thing that hasn't been mentioned: You also need to earth your generator to the house earth connection. I think that's shown on that page, too. Safety reasons, obviously.
HTH,
Pop
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rh455 wrote: > John, in doing some research I found that the biggest fear of most is > that the main breaker may fail while in the off position thus still > allowing power flow as if it were still on. I suppose that this cenario > is still possible with an interlock kit. Is this right? > > > Pop, I don't have either switch at the moment, but don't I have to do > both of the steps you listed regardless of which switch I get? With a > cutoff, I go outside, throw the cutoff and lock it down. Then connect > the generator and turn on the circuits that I want. With a transfer > switch, I have to turn the main switch on the transfer switch from > utility to generator, connect the generator and select the circuits > that I want to run. Did I miss something? Aren't I doing the same steps > regardless of what switch I choose? > > Another problem I'm facing is that the breaker box in my house is in a > confined area, barely wider than the box itself. I won't have any place > in the immediate area to install the transfer switch. From all ads I've > seen, the harness is only about 2'. The wall that the breaker box backs > up to is the breakfast area, so Wifey won't be thrilled about that. Any > ideas?
That is a straw man put forward in an attempt to answer those who say that they would never forget to open the main first. I don't see a failure of a main breaker in the closed position as at all likely. What I do see as likely is that the user will be tired, stressed out, drunk, or elsewhere. If the user is elsewhere then their no it all teenage child, fed up with no power wife, or ever so helpful neighbor will attempt to use a system were a single mistake in two separate operations will cause injury of death. With the interlock kit and a fixed male inlet there is no way to make a deadly mistake with a suicide cord or a back feed to the outside utility lines. In forty years of electric work I have never seen a main breaker fail closed. I have however seen more than a dozen of them fail open or unable to reset after opening on repeated overloads.
To overcome your limited space you can mount a SquareD rain tight, feed through panel out doors between the meter and the point of entry of the service conductors. That panel will contain the interlock kit. It will also provide you an outdoor source for air conditioning, well pump, outbuildings, jacuzzi, or any other outside load. The flanged inlet; such as the one shown at <http://www.electricgeneratorsdirect.com/catalog/default.php?cPath !_27>; can be mounted right at the feed through panel. That will put your generator operation all in one place.
If your home has any form of dual metering such as for off peak use of AC or heating then you need to have the installation checked by an electrician experienced in emergency power installations to eliminate any possible sneak current paths between the two meters via equipment served by both.
You won't have to select the circuits as long as you don't turn on too much load there will be no problem. -- Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
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