There are several ways to use a generator for backup power.  I will try to go over the best ways, and the effective but not quite right ways....  and point out some things to consider safety wise.  I am not going to promote brands or fuels or even get to involved in wattage considerations.

1. The simplest way to use a generator is thru extension cords.  Use good quality 12 gauge or maybe even 10 gauge depending on the length of run.  Hooking up a refer or freezer is pretty obvious...  but how to hook up the boiler or furnace?  My suggestion (for the typical installation) is to pull the feed to the Firematic out and put it in a 4x4 box with a 20a receptacle and a raised cover.  Then put a piece of 12-3 SO cord with a quality cord cap and a strain relief connector into the J-box that the Firematic is mounted to and plug that in to the outlet.  When you need to run the boiler off the generator just plug it directly in to the extension cord.  You can also make up a 220 volt cord and do the same thing for a well pump.

The good points about this is that it is easy and foolproof and legal.  Its a great way to go if you are a renter.  Its also very flexible....  if you want to help friends and neighbors out its pretty easy.  The drawbacks are good quality long cords are expensive and have a tendency to wander off and its not always handy for powering up some little things like lights and radios.  You also may need to leave a window or door cracked in cold weather to run the cords thru.

2.  Less ideal, but effective, is running a cord straight in to your electrical panel and back feeding it.  The best way to do this would be to run a heavy duty 10-3 or 4 (assuming a 30a power source) and hook it in to a 30a breaker in your panel.  Most generators around the 5,000 watt size will put out 30a at 120 and 20 a at 220.  Depending on your electrical needs I like to shut off all 220 breakers and put a jumper on my back feed breaker so I can run everything in the house at 110.  That means I use a 2 pole breaker and connect both sides with a jumper to the black wire.  The white wire goes on the neutral bar and the green wire goes to ground.  This lets me have lights and radio as well as running fridge, freezer, and boiler.  My only 220 breaker is a stove so that's not an issue and I don't have any shared neutrals in my house so overloading a neutral is not a concern.  To do this safety you need to make 100 % sure the main breaker is turned off!  Check and recheck.  Pull the meter if you have to!

IF ANYONE HAS A PIC OF THIS IM OR EMAIL IT TO ME AND I WILL PUT IT IN HERE.

The advantages to this method is that you can have lights and utilities as usual.  This is not a bad way to go if your area has just been hit with a devastating storm and it may be days or weeks before you will get power back and you have access to a generator.  Its cheap, usually cheaper than the all extension cord method.  If you are working toward a transfer switch system you may have bought these parts first and have them on hand.  You may have to shut some things off and cycle them so you don't overload the generator, but that's not hard to do. The disadvantages are that it is not so foolproof and the result of a mistake could cause damage to the generator, fire, or back feeding to the utilities and potential death to a line worker.  Its illegal and insurance companies probably wont cover you in the event of an accident and a court would probably find you negligent if personal injury or death was a result of your rigged up system.  You may find electricians that will do this to help a friend out or themselves...  but you wont find any to do this for you and send you a bill.  It is a violation of the NEC and if someone died could send them to jail!

3.  The next simple, basic system is the interlock kit.  Basically it is a custom, UL listed bracket that allows you to permanently wire your generator in to your panel without any transfer switches.  The bracket assures that the Main and the Generator breaker can not both be on at the same time.



The advantages are it is simple, UL listed, and fairly foolproof.  It is not as cheap as it looks like it should be.  It allows you to try to run the whole house, but you will probably have to shut most things off and run a load within your generators capabilities.
As an electrician it does not really make me feel warm and fuzzy because it does not physically assure that both connections cannot be made at the same time...  but its much better than method number 2.  And it is UL listed which makes it more insurance friendly!

4.  The next cheapest and easiest way to hook up a generator to your home is with a small emergency panel transfer switch.  Some of these will only do 4 circuits, but you can get them bigger.  They are pretty self explanatory and the average handyman can do it themselves pretty easy.  They are simple enough that with a quick lesson anyone in the family can figure out how to run them.



This is a small one with a built in plug rated for a 12500watt generator and the cost is about $440.




Just to show a different one this is rated at 7500 watt and costs $446 and is hard wired to a remote receptacle.  

These can be nippled right in to the panel and connections are easily made.  The advantage is that they are easy to operate and hard to make an error.  You will know when the power comes back on because everything that is not on the small sub panel will come back on.  The disadvantage is that they will only power up a limited number of circuits.  If you have distinct summer and winter needs and limited circuits you may have problems.  

5.  Another alternative is A/B panels, one I have never installed, is a small sub panel with your critical circuits and fed by a three position breaker that can be fed with utility power and generator power and breaks one before making the other.





This one is at Home Depot for $442 and includes the 6 circuit panelthat is expandable to 16, remote weather proof receptacle, cord and wires.

Advantages are its UL listed, safe, and simple to operate.  It probably should have a real electrician install it because of neutral and grounding issues.  I will get in to neutral and ground issues at the end.

6.  Now we get in to transfer switches, both manual and automatic. This is where things can start to get complicated.  If you want to switch your whole house ahead of your main breaker you will need one that is Service Duty Rated which means it wont turn to plasma if you have a transformer problem.  You can save money by putting in a sub panel and going with a regular duty rated transfer switch.  I guess this is a s good a point as any to get sidetracked with the neutral switching issue.  Typically, in residential applications (I am staying away from commercial work here), the neutral is not switched.  The main reason for switching it is if you are trying to run delicate electronics and want to protect them from potential line surges.  If you do choose to switch the neutral make sure your switch has last break, first make capability so you dont run the risk of a neutral being the last to make and running the risk of a 220 backfeed situation.

 

This is a 200a Service rated manual transfer switch going for $469.  It allows you to run everything that your generator can handle in the house.  If you have a small generator now you can upgrade at any point and run more and more of your house at once.



This is a nice installation from a member here...  hope he does not mind me using his picture!



http://i307.photobucket.com/albums/nn297/blackhawkhunter/Eaton-RLC1-200se-inside.jpg



This is a Service Duty rated 200a automatic transfer switch.  This also can power your whole house depending on your generator size.  It goes for about $1300.  The advantages are its automatic, when the power goes down your generator will automatically start (assuming its electric start and compatible) and you will be without power for a very short amount of time.  If you are away from home you do not need to worry about your house freezing up or food spoilage.  It will also automatically exercise your generator so it stays in top shape.  The only disadvantage is the cost.  If you start out with the manual transfer switch you can grow your system from there.  With a switch matched to your service you can increase the size of your generator as you have money...  then you also have the option to change the manual switch to an automatic as you have the money.  Obviously with the automatic switch you want a generator with a bulk fuel supply because it can run unsupervised.

7.  Now a little about grounds and neutrals. They should be tied together once in your system...  at the main overcurrent device usually.  If you have them tied together at various points your ground wire can become a current carrying wire.  Parralel grounds and neutrals can also increase resistance so your overcurrent devices do not clear faults as quickly as they should. Hopefully your house was wired correctly to begin with, but now you are adding a generator.  I bet most of us use a small, stand alone generator, probably in the 5 kw range, with built in receptacles and over current protection.  Because these come with the neutral and ground bonded its easy to end up with parralel conductors.



This diagram shows the neutral and ground bonded at the generator and that in this case the neutral should be switched in the transfer switch.



This shows a seperated neutral and ground at the generator and a solid neutral at the transfer switch.

In most cases everything will work just fine with the neutral and ground bonded in two places....  however if there is a fault somewhere the grounds can become current carrying conductors and electricity can appear in odd places.  Because of the increased resistance you will also get heat which can cause fires.  There was someone in SF that was pretty creative and installed a switch on the generator to make or break that bond depending on how they were using the generator.  I thought that was a pretty darned good solution.... simple and universally effective.  

Its easy to make electricity work...  its harder to do it safely!

Misc considerations....  

If you are wiring up a new house consider putting all hall and kitchen lights and garage lights or basement lights on one circuit...   That way if you put in a generator with limited capability you can put that circuit on the generator and be able to move around the house.  Also consider a receptacle in the kitchen for a microwave or coffee pot on one of the generator circuits.

Hope this is not too disjointed....  this week work is really busy so its been a piecemeal project.

OK, let the fireworks begin!  

Back feeding is damned dangerous and illegal in many places.

The transformer that steps down the voltage to feed your house also works in reverse, stepping UP the juice on the way out and some poor SOB fixing the "dead" lines will get fried.  Don't do it.

You can easily do it through the dryer outlet IF you have an electric one.  I call it the suicide setup.  Not suggested.

Instead - do it right.  get an A/B panel and feed through it.  In this way, your street power runs through the panel and if you have no street power, simply switch off street and on generator.

Run the panel feed out the wall where your box is mounted to a sufficient (240) outlet.

Make a cord to run from your (outside power source, i.e. generator) to the outlet.

Generator cost (5500/8500 spike) is about $700
Panel install by an electrician is $500-$800

So for $1200 to $1500 you are safe and sound.  Well worth it IMO as in the winter you are in a glorified cardboard box without any heat.

I am set up to run heat, well, washer, dryer, stove, microwave, 2 refrigerators, a couple of outlets and one complete bathroom.

Power goes out and i can live pretty much the same as I did before it went.  As long as I have fuel.  5 gallons runs me for 12 hours.  I usually have 45 gallons (15 stored and 3 cars partly full).  I have a siphon kit to get it out, so I can last a good long time especially figuring you could run for a few hours (say 2 at a time) and get everything done, then cut off the generator.

I figured someone would be a peckerhead and jump the gun!  Some people just cant read instructions!

Hey slow down there buddy - its MR. peckerhead to you!

BTW - thanks for your post - I just got a Honda 3000is and I'm interesetd on how to hook it up to my electric service. I'll be following this thread as it goes...

Nice - just like mine (the peckerhead)

I bet when you see a sign that says "wet paint" you just have to touch it!

Well- ya just gotta know - you know?

Actually I can't see pics at work- they are all blocked.  That didn't help.

OK - so what did your setup cost ya and what is spike or peak output?

I'll read the original post; it may be there

Edit: spelling

blackhawkhunter, a question about #5. The sub panel in the picture, is that a special sub panel, or is it a regular sub panel with a special 3 way main breaker added?

Let Mr. Peckerhead reply!

Special sub panel - commonly know as an A/B panel.  Called that because it is either A (Street power) or B (generator power), but impossible to do both or to backfeed.

OK blackhawkhunter - did I do OK?

I went with the same GE safety switch at my house that's in #6

I have seen too many breakers fail over the years.

Great write-up.

blackhawkhunter or any one that may be in the Know, If I have a service entry rated transfer switch like the GE one in Pic 6.  What would I expect to pay on the install.  I have, a Cuttler Hammer one, and was wanting to get it installed between the meter and my 200 amp main pannel. My gen set is small, only 8000kw, 13000, surge and I know that I will have to shut off a lot of breakers to run the gen set, but I expect to upgrade in a few years and would like the flexability of having the whole pannel available ( I actually have two pannels. A 200 amp main and a 100amp sub)

Assuming you have the physical room it should be fairly easy.  Depending on how the grounds and neutrals are landed in your main panel they may take some time to seperate...  or it could be a one minute project to remove a bonding jumper.  The meter would have to be pulled, probably SEU routed to your transfer switch, then SER to your main panel.  If its straight forward I would guess about 4 hours by the time they were ready for power to be turned back on....  buts its hard to say long distance without seeing all the details.

Yes sir Mr Peckerhead!

Cool!  

I do what it says and pee on it. And those "Wet floor" signs, well...I can't/don't go to the local K-mart anymore.

Back on topic, that was a great writeup. I'll be saving it for future use as well as forwarding to my FIL who needed it after Ike. Maybe this will inspire him to follow through.

sgt_seti

I saw a wet floor sign in the the store today and had to laugh!!!!

Feel free to ask any specific questions...  I was just looking to give people a good idea of options.

I am quite suprised  I have not seen a bunch of people advocating suicide cords and other such dumb ways of powering things up!

I’m not an electrician, so bare with me!


1) I don’t get the “increase resistance” statement. Wouldn’t paralleling the ground and neutral double the current carrying capacity of that leg?

How does this affect the trip rate of the breaker?

2) Let’s use a scenario of a genny with the ground and neutral tied, then back feed thru a dryer plug (main switched off). Wouldn’t the grd & nut only be parallel until it got to the dryer’s breaker in the panel? I assuming the grd & nut are tied to earth grd here. I don’t see how this is a problem and how it increases the possibility of fire.

What am I missing?

Good question.....  lets see if I can explain it in human terms.

Short a wire, hot to ground and the breaker should trip due to the massive inrush of current.  Add some resistance and short that wire hot to neutral and your breaker will be much slower to react...  it will think its a heavy load on that circuit and will take much longer to trip the breaker.  Depending on the resistance, the breaker may not trip at all.  Now do the same with the neutral and ground paralleled and you will have energized anything that is grounded with a three prong plug.  Some of these items will provide enough resistance that the breaker may not trip, but they will be energized.  Even the frame of your generator standing out in the snow in the driveway could become energized.  Also, even under normal operation your grounds are now carrying a part of the return current.  If you happen to touch a grounded appliance and a well grounded surface you will become part of that return current path.  Remember it takes milliamps to kill you!  

With regards to resistance...  I have been told (but never tried) that if you wire nut one end of a 1,000 foot roll of Romex together, put 110 volts to the other, the resistance is so great that it wont trip the breaker.  Might be false....  But remember resistance equals heat.... and heat can equal fire.

This may not happen every time, but it will happen more often with the ground and neutral paralleled.

Somehow I dont think I did a good job explaining this....  if anyone can help feel free to jump in... and I will give it some more thought and try to explain it better.

tagged for future upgrade

Hello Blackhawkhunter:

Thanks very much for posting this. I have already referred several friends to this thread!

I have a question: I have a 3500/4000W generator with a L14-30P plug on it. I'd like to use one of the panel interlock kits to wire it into the panel. I understand two legs are supposed to be hot, one is ground and one is nuetral.

1) How do I find out if I have a floating nuetral or a nuetral bonded to frame?

2) In using this generator, is it wise to prepare a ground rod and upon using the generator ground the frame to the ground rod?

3) Presuming I am using the panel interlock kit, do I wire the ground and nuetral in the panel as I would any other run of 220v? That is, the two hots to the 220 breaker (of course) and the ground the nuetral to the nuetral bar? Sorry if you already explained this and I didn't get it.


I understand that this generator is not a large one, and I will have to do some pretty drastic power management, but if I can run a few lights and the furnace (winter) or refridgerator (summer) I will be happy. If Santa brings a bit bigger generator and I can run the well pump too -230V @ 6.4A- I will be VERY happy!


Thanks for any advice you can give.

Stay Safe,
AGreyMan

Hey Doc, good questions!

Let me answer in installments since I am really busy.

1.)  Check for continuity between the neutral slot of the receptacle and the frame of the generator.  You can also check in the owners manual, usually they will say somewhere in there.

2.)  Assuming you have a wheeled portable generator you do not need to specifically ground it.  However, if you either find you have a floating neutral or decide to seperate the neutral and ground at the generator then I would suggest putting a lug somewhere on the frame and having a permanently installed ground rod available.  

3.)  Will finish later, its a, if this, then this sort of answer.

The next simple, basic system is the interlock kit. Basically it is a custom, UL listed bracket that allows you to permanently wire your generator in to your panel without any transfer switches. The bracket assures that the Main and the Generator breaker can not both be on at the same time.

blackhawkhunter, Where would one purchased such a device as I have a CH panel and this is just what I'm looking for.........Thanks........carbineman

http://www.interlockkit.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=CH

Did some looking and found this thread....  good info!

Very good writeup. It makes it much easier to explain things to people with pictures, and obviously you are a master of Paint.

As far as backfeeding goes, if you do it wrong, you can get people killed. It is that simple. Electricians only do it for close friends because of the liability involved. I am going to be disconnecting one later today, and might take a picture of it, but then again, that opens up a can of worms as far as liability goes. I'll see if I can find a smaller panel that isn't connected to anything to demonstrate it on. It is pretty simple though.

One note though Blackhawk, I would add as another part of hooking up the furnace with the cord end to connect it to the line side of the Fireamatic, and to make sure the breaker is turned off in the panel to prevent backfeeding. That way if your furnace or boiler catches fire, the Fireamatic can still operate as intended, and at the same time you don't fry one of the guys playing in the cold weather to turn your lights back on.

Remember, when sizing a generator, and say it has an L14-30P twistlock connector, that doesn't mean you can only run two 15A breakers on it. Your breakers are sized based on the wire size used for the circuit, not the actual load (for houses at least). As an example, with a 1400w Honda generator, we connected it for someone so that they can run their boiler (with a slick Rielo burner), fridge, freezer, and few lights, all on that generator. Also keep in mind that you only use generators during emergency situations, so you aren't going to be cooking a turkey while doing a few loads of laundry while filling your pool out back. Only run what you need to, but make sure the genset is large enough to keep you comfortable. Some people only need heat and lights, some want heat, water, and lights. Keep in mind though, if you have an electric water heater, that it really limits you in how much other circuits you can have on when that thing runs. You are dealing with pretty high, steady wattage when those heating elements are running, so my suggestion would be to get your heat working first, and once the house is up to temp (set your thermostat higher than normal just to keep it comfortable longer), then shut off the boiler/furnace, and run only the water heater for a while, then worry about taking a shower or what have you.

If you have an electric oven, don't use it. They can use a shitton of electricity, and LP/NG cook better anyways.

It may sound great to run your whole house off of one of those safety switches, but keep in mind what you may have had running when the power went off. If you had a coffee pot going and a hair dryer or something, and then all of sudden you throw that big happy switch, and you get those 2 fairly large loads starting at teh same time your fridge compressor motor is ramping up and your freezer, and your furnace's blower, you can easily bog that generator down to the point where it trips the breaker. Be smart when you start loads.

As far as grounding the frame of the generator goes, you shouldn't need to since it should be grounded to the grounding conductor that is part of whatever receptacle configuration it has, so as soon as that gets connected to any house ground, your generator is grounded. If you have a large 8.5kw or greater, standby generator, then the grounding lug on the genset is electrically connected to the frame anyways, so you should be set in either case.

Did you get much work from this last storm Blackhawk? I got 12 hrs on Friday, 9 on Saturday, 6 on Sunday, 9 on Monday and 8 on Tuesday out of it. Only problem is that I didn't work yesterday and will only get a few hours in today, so it will average out, but hell, I have fun doing emergency work.

Either you missed it, or I didnt say it very clear, but I think I said to pull the feed out of the Firematic and put it into a box with a receptacle.  Then run the SO cord into the Firematic.  That way, when you unplug the cord from the receptacle you are isolating it from the panel source.  Then when you plug it in to your extension cord you are still getting the protection of the Firematic.

I am not in that line of work any more so no OT for me.

I'm planning on going with one of these interlocks when I get out of this damn condo and into a house.  I thought that the only reason these devices existed was to physically assure that both connections cannot be made at the same time.  Can you elaborate on this?

You are correct.  Its just a way to mechanically assure you cant back feed the power line when the breaker to your generator is on.  Its simple and fairly foolproof.

The benifit is that you can custom tailor your loads for the season....  ie, fridge and freezer take precedence in the summer and boiler/furnace in the winter.  If you want to watch the big game on TV you can do that after your other loads are satisfied.  You can have the outside lights on if you are working outdoors.

Its not my favorite way to go, but it is probably the most economical and simple way to go.

Added to favorites for future use... thanks!

tagged for future reading