Generator and Interlock basic questions...

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  #1  
Old 11-05-12, 07:54 PM
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Generator and Interlock basic questions...

Hey guys,

I live in the area affected by Hurricane Sandy. As such, I have been running a borrowed generator for heat/basic lighting. I'll admit it is a rigged extension cord situation. I have heat and a single light.

Anyway, after looking around a bit, I have decided to install an interlock on my breaker box, along with a plug in box outside. I plan on buying the equipment and installing the plug outside and running the 10/3 plus ground wire to the pannel. I'm going to grab the piggy back breakers and generator breakers and have a licensed electrician install the actual components.

After looking around at generators and what not I have come to a few questions that I don't get. First off, the four pin locking plug on the generator says 120/240. Which one is it? And how is the proper voltage selected?

Second, the 10/3 plug ground wire connects to the four pin box. What are these four wires? I'm assuming hot, neutral, ground and something else. Maybe this has to do with the 220? Perhaps two hots, one neutral, and a ground?

How does this affect the generator breaker? And how many wires go into this breaker from the 10/3 plus ground wire?

Thanks for the help. Like I said I will have an electrician do the hookups. I just want to order the parts and run the wires to save the cash on install. I just want to know how this thing works for my personal knowledge.

Take care,
BC
 
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Old 11-05-12, 08:13 PM
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I will have an electrician do the hookups. I just want to order the parts and run the wires to save the cash on install.
Many electricians for reasons of liability won't want to do it that way. They may also charge extra for redoing work not up to their standards. Actual hook up isn't that hard. We can walk you through it.
 
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Old 11-05-12, 08:18 PM
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The four wires are Hot, Hot, Neutral, Ground. If you connect something between the two hots, you get 240v (such as a water heater). If you connect something between one hot and neutral, you get 120v for lights and such. That's why you need a 4-connector plug and either 10/3 + ground NM-B or 10/4 SO wire. (either option has 4 wires, just someone in some standards committee decided to confuse everyone)
 
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Old 11-05-12, 08:24 PM
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Since you do not understand the 120-240 connection it is obvious that you do not have the understanding necessary to even order parts. Please, for your sake and for the sake of your loved ones, buy the book Wiring Simplified and read it cover to cover. Wiring Simplified is a book that explains in layman's terms HOW and WHY things are the way they are in electrical systems. The cost is less than $10 and it is available from many on-line booksellers as well as usually being available in the electrical aisle (NOT the books and magazine section) of your local mega-mart homecenter.
 
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Old 11-05-12, 08:42 PM
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Thank you very much to all of you. Furd I will buy that book and check it out. I wasn't planning on just haphazardly ordering parts. I was going to order the kit for my breaker box that included the interlock, piggy back breaker, generator breaker, and outdoor plug housing. But I get your point. Thanks to everyone else for explaining the four connections, I get it now.

One more question. My panel is an older bryant. There is no space between the main and the breakers, two slots to the left of the main, and the remaining slots are filled. It is similar to this picture, but I have a lot less breakers below the main:

K-3110 Interlock Kit

Are the two spaces to the left of the main usable for breakers? Or are these dead slots?

Thanks again,
BC
 
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Old 11-05-12, 09:07 PM
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I know that you want to do this correctly and I apologize if I came on a bit too strong. Electricity is an equal opportunity killer and things MUST be done correctly to minimize the hazards. You need the background just to know what questions to ask.

For example, I have no idea of what "piggy back" circuit breaker might be. The generator breaker in a service (main) panel must have a hold down device to prevent it from being removed when the panel cover is removed. The "outdoor plug housing" is properly referred to as a generator inlet connection and it must also have a rain proof "in use" cover on it. It is the little things that will trip you up badly.

You really need to post a picture of YOUR panel and not a generic picture of a similar panel. Some jurisdictions do not allow a field-installed interlock, some do not allow interlocks at all and many panels cannot use interlocks by reason of their construction. With you having an older Bryant panel you may have what is called a "split bus" panel and installing an interlock may not be possible. Interlocks sound like a good and simple idea at first but they also have many drawbacks.
 
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Old 11-06-12, 07:40 AM
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It's not a problem. I know that many people take the responsibility of their electrical system lightly, ending in property damage, personal injury or death. That being said, I have not ordered anything and have not started anything. It is only a rough draft, if you will, for now. Anyway, Let me get into what my plan is/was, and perhaps you can tell me if I am on the right track.

This is my breaker panel:
imgur: the simple image sharer


As you can see it is full except for the upper left two slots. In order to install the generator breaker, I need the two slots below the main. If possible, I would like to relocate two breakers to the top left two slots. If not, I had intended on using "piggy back" breakers. These are breakers that allow you to put two breakers in one slot, and are sold on the interlock site. Also, I was planning on buying the BR generator breaker from the same page. They are linked below:

Generator InterLock Kit - Accesories

** On a side note, there is an extra breaker in my panel that is no longer in use. It used to be connected for a pool pump, but I do not have it in my house anymore. It remains off, and presumably, I could eliminate it for a reduction to just one piggyback breaker. ***

Further, I intended to buy the Convenience Inlet Box from the, which is reported as waterproof, along with the four pin extension cord. Both rated for 30amp.

I live in NJ, in a regular single family home. Does this sound like something doable?
 
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Old 11-06-12, 08:06 AM
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Probably just because I'm not a pro but I don't see a main breaker in the picture.
 
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Old 11-06-12, 02:42 PM
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Ray, I'm pretty sure the top right circuit breaker is being used as a main circuit breaker.

bcamp, that panel may not even be "listed" for use as a service (main) panel as it is more commonly called a "load center" and would normally be used as a "sub-panel" fed from a service panel. It is possible that the two blank spaces to the left of the "main" cannot be used in the present configuration.

Do you feel comfortable in taking he cover off the panel? If yes, use a sharp utility knife to score the paint all around the edge of the cover to prevent damage to the paint when removing the cover. Don't touch anything inside and take a picture. Also take a picture of the label in the panel door.

What you and the Interlockkit site are calling "piggyback" circuit breakers are more commonly known as twin, tandem or dual circuit breakers. It is quite possible that your panel will not accept them.
 
  #10  
Old 11-06-12, 05:59 PM
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The 100A 2P breaker at the upper right is the factory installed main breaker, see the retaining screw? This is a 12-20 panel. There are spaces for 12 full size breakers. The top 4 slots on each side will accept tandem breakers and the bottom 2 slots on each side will only accept the full size breakers. Yes, this is suitable as service entrance equipment. If you look at the diagram in the panel, the two spaces to the left of the 100 amp main breaker will not accept and breakers, there is no busbar there.
 
  #11  
Old 11-11-12, 06:29 PM
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Thank you all for the replies.

Furd: I took your advise and bought that book. Interesting stuff. After some research I decided that the only way I could put an interlock in that panel would be to add more two pole breakers, and i am not a big fan of doing more of that. That being said, I would like a dedicated 20amp for my garage outlets so I don't trip the circuit when I'm grinding or using other higher amp tools. So I decided to update my panel to a larger one, which would allow me to add the generator breaker, the new garage breaker, and have a few slots for who-knows-what-else later on.

That work, however, will be done by an electrician, as I am not comfortable with it. Light switches and receptacles I can handle, but changing out the whole panel I will leave to the pros.

Thank you for all your insight and recommendations.

-
BC
 
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Old 11-11-12, 07:03 PM
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ReRead post # 10 from casual joe.....it tells you how many breakers this panel will handle safely. It's posted on the door of your panel. It shows 12 breaker spaces and where doubles can be used for a total of 20 circuits.


On edit: Good move in replacing the panel.
 

Last edited by PJmax; 11-11-12 at 07:04 PM. Reason: updated reply based on previous post
  #13  
Old 11-12-12, 07:17 AM
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I decided to update my panel to a larger one, which would allow me to add the generator breaker, the new garage breaker, and have a few slots for who-knows-what-else later on.
I think that's a wise decision and want to make a few more comments and suggestions. First of all, I didn't catch this the first time, but the interlock kit you were considering isn't U.L. Listed and probably would never pass an inspection by your AHJ. Bottom line is, you shouldn't use it or any other products from any company that aren't U.L. Listed. I did see where they state their products are tested to U.L. standards, but that means nothing. Now, when you have your panel replaced, be sure that you are getting a panel from a manufacturer who also manufactures an interlock cover for that specific panel. Just because you have a new panel installed doesn't mean you can get an interlock cover for it because most manufacturers don't make interlock covers for their entire product line, so check it out. Best thing would be to have your contractor furnish both the new panel and interlock cover now so you'll have it when you need it.
 
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Old 11-16-12, 02:15 PM
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CasualJoe,

Thank you for the reply. I talked to my electrician who stated that he will be installing a Square D or Cutler Hammer panel, with a cover that has an integrated interlock. He said this was the preferred method, as the brands are not conflicting and it carries a UL listing. So I suppose that solves that issue before it's a problem.

-BC
 
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Old 11-16-12, 06:09 PM
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Originally Posted by bcamp
a cover that has an integrated interlock.
He said this was the preferred method,
I think that you will find that most of the moderators hate interlocks,
and fervently believe that interlocks are basically murder with a screwdriver.

and I'm currently playing devils' advocate,

if - interlocks can fail = murder
then - transfer switches can fail = manslaughter
 
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Old 11-16-12, 07:06 PM
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Hal_S.... I'm not quite sure what your posts are trying to accomplish

Devils advocate....why....bored ?

I have never seen or heard or read of a UL listed transfer switch EVER connecting both the street and generator together. I've read your multi posts. I've read they've failed....yes they do. I read the one where things fried when it tried to connect both. It didn't connect both and that wasn't the cause of the problem. People post about problems without even knowing the problem. Transfer switches are designed never to connect both power sources even if the malfunction.
 
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Old 11-17-12, 04:58 AM
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Originally Posted by PJmax
Devils advocate....why....bored ?
Nope, a couple of post in other threads mention "civil and criminal liability" which frames some interesting issues about knowing that something can fail or safety measures can be defeated.

What is the level of responsibility when using something that CAN malfunction?
Yes, an interlock could be defeated by removing the panel.
Yes a transfer switch could be defeated by removing the panel and dropping a box wrench across the contacts.

Colonial definitions had murder and manslaughter; modern ideas use purposefully, knowingly, recklessly and negligently.

The basic idea here
- how do you deal with forseeable misuse or misunderstanding-
- how do you classify when something IS forseeable?

It fits into something I'm writing...
 
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Old 11-17-12, 05:26 AM
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Things that can fail, will fail. That is a given. The point we have been hammering is that there is no interlock that is tested and APPROVED by a governing body or testing laboratory. Transfer switches are tested and approved. You stated that we hate interlocks. No we hate the aftermath of the misuse or failure of such an untested/unapproved device when they can be physically and intentionally defeated. Prudent use of transfer switches can cause no connection between the generator and utility. If you are using us as a sounding board for a book, listen to what we are saying rather than interjecting unsafe methods to DIY'ers who can get hurt with your suggestions. Safety is of utmost importance to us.
 
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Old 11-17-12, 07:44 AM
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The original poster wrote:
I talked to my electrician who stated that he will be installing a Square D or Cutler Hammer panel, with a cover that has an integrated interlock. He said this was the preferred method, as the brands are not conflicting and it carries a UL listing.
That is key here. Not an untested add on but a interlock that is part of an inspected and approved manufacturing process. What the O/P is doing is just fine.
 
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Old 11-17-12, 09:01 AM
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Originally Posted by chandler
there is no interlock that is tested and APPROVED by a governing body or testing laboratory
Originally Posted by ray2047
a interlock that is part of an inspected and approved manufacturing process. What the O/P is doing is just fine.

Read more: http://www.doityourself.com/forum/ne...#ixzz2CV2HI9Ld
a interlock that is part of an inspected and approved manufacturing process. What the O/P is doing is just fine.
(emphasis added)
Now you see why I've been asking questions, (aka playing devil's advocate).

Two knowledgeable moderators, different positions.

Not trying to be confrontational, but trying to unbundle the through processes to understand why two bright people come to different conclusions.





So, the above is ANSI certified and UL listed?

Then, is it approved?
 
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Old 11-17-12, 09:26 AM
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Hal, the difference is the "add on" and the factory built in interlocks. Apples and Oranges. My choice did not include the factory ones. So my error. I believe you will find this interlock is part of the switch gear and not part of the cover as most are, and can be defeated by removing the cover. That is our point

Ray has stated the bottom line. The OP is using a factory installed interlock, so he is fine.
 
  #22  
Old 11-17-12, 09:39 AM
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Originally Posted by chandler
Originally Posted by ray2047
Originally Posted by bcamp
he will be installing a Square D or Cutler Hammer panel, with a cover that has an integrated interlock.

Not an untested add on but a interlock that is part of an inspected and approved manufacturing process. What the O/P is doing is just fine.
and not part of the cover as most are, and can be defeated by removing the cover.
...
The OP is using a factory installed interlock, so he is fine.
And, now I'm more confused than before.

No interlocks are approved.
Panel interlocks are always bad.
Factory panel interlocks are not bad.

I don't see any continuity between the moderator's answers.
I'm missing something, but I don't know how to resolve the paradox.
Eh, I give up.
 
  #23  
Old 11-17-12, 10:50 AM
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He meant add on interlocks as he clearly explained to you in his last post.

This thread is closed. If you feel the need please start your own thread.
 
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