All,
Having been through four hurricanes this season, I've acquired a little info on this topic. You are required to have a manual or automatic tranfer switch if you intend to "backfeed" into your abode. If the power company determines you are backfeeding without a Transfer switch, they will take your meter and you will have to pay them to come back out and reinstall it.
Secondly, I do not believe it is possible to syncronize two house generators. With varying loads and small gas powered engines you would be in and out of phase constantly. This would pop circuit breakers very quickly (instantly).You will need a designated cord for the second generator to operate designated electrical equipment in your home.
Be grateful you have two generators, I was without power for 6 days after Frances.
KingFisher

 

Something elkse to consider. In the event of a declared emergency, FEMA can (and does!) confiscate lots of generators that are wired improperly into the mains.

BTDT

 

It's not that simple. You have to syncronize generators together. There are considerations such as voltage, frequency and phase angle. Voltage means that if they are not matched, reactive power will flow. Frequency means that both generator have to be at the same frequency. Not necessaily 60 but at the same frequency to have the breaker closed otherwise unwanted power will flow. Phase angle means that the two generators have to have the same peaks and valleys. Both generator could be at 60 hertz, but be doing that 180 degrees apart. IE One hand up and one hand down. Now reverse them at the same time. That is 180 degrees out of phase.
Jim

If you don't need 240 volts, why not hook one up to one side of the panel and the other up to the other side of the panel. You cannot run 240 volt appliances but more 120 volt stuff will work. If you did run a 240 volt appliance, something will burn up as you are tying the generators together. Also power companies also have a thing called a joint load controller. What it does is load both generators up at the same time as more power is required. It is not as simple as some tIthink.

 

How would one know what size generator to get to power your house?
I'm no electrician, as you can tell, my next question would be how to "plug" it into your house?
Our elec goes out every time it rains, seems like. Might be worth it for me...
99PSDCREW

 

99PSDCREW, most people with a genset use a haevy guage cord that plugs into the big outlet on their generator, the other end has a male plug that will fit in a dryer outlet. What you get then is your main panel will have power to it, and you can run your house like normal. *(see next paragraph.) You have to turn the main power off first or you will backfeed the entire neighborhood and burn out your generator.

AS far as size goes, to run some of the house you will need at least a 5000 watt genset. I have a 7550 watt genset. Mine will run central air for a 2 story house, the fridge, lights, even the computer. If you buy too small of a generator, and put a big load on it you will burn it out.

When shopping for a genset look at the specifications for that model. Don't be fooled by a manufacturers claims for wattage. Some manufacturers advertise using the surge wattage (which is higher than continuous running wattage), its a shady business practice. Surge wattage is the extra oomph some electrical devices (especially those with a motor) to get running. Kind like your truck, takes more fuel to get it going to 60 MPH than it does to cruise at 60 MPH. You should see two wattage ratings when you look at Surge wattage and continuous running wattage. For example my genset has these two :

Cont. Running : 7550
Surge : 13,500

Click
here for a good link to portable generators. That company made my generator. Mine is a Generac 7550 EXL, its a good genset. Mine is about a year or so old and has a 14 HP Briggs and Stratton. The new 7550 EXL's are coming with 15 HP B&S engines.

That link above can also help you determine how big a generator you need.

Hope this helps.

 

Oops, double post.

 

J.R. is right. Mine is a 5000 watt or 5 kilowatt model. Don't get one that is too small. My 1st one was 2000 watts. I then checked my kettle and it uses 1700 watts to boil water. If the power was out, all I could do was boil water in the dark. All I want is to be able to run the gas furnace in the winter and have a few lites on and maybe the TV. Mine cost $450. in U.S. dollars. Another thing to consider is what to do if you have a gas furnace and the gas goes out but the electricity stays on. This happened close to us one year. -35 and a 25 mile wind. Then you need a 240 volt portable heater to shove in the furmace if you can get the furnace motor turning. Lots of considerations.
Jim.

 

This is a bad idea for a couple reasons I am not even going to comment on. If you want to hook a feed to the house get a licenced insured electrician to do this job. We give all kinds of DIY advice here and even DIY wiring for some jobs where they are simple and can be done by a careful compentent guy with some basic skills and some tutoring. This is not a DIY job for an amateur just learning basic wiring. It isnt just yourself you are endangering is some unsuspecting lineman or someone else working on a system. A couple of DIY sites have stopped taking genset questions because of this. A lot of advice is given,, well why dont you just do this or that, plain bad advice from here as well as other places. There are established safe proven methods for this job and none of them start with "why not just do this"

 

JRs & Sberry,
Thanks for the information. I'm checking this out now.
99PSDCREW

 

Well, I didn't expect to figure out the generator stuff here, but thanks for the info. I'll be heading back to an island where the power grid may be out for a few more months. I've got a generator on the way ahead of me.

Can someone check me to be sure I've got this right:

• If I just run the generator into a heavy duty outlet such as the clothes dryer it will then power my house, assuming that the remaining wiring is intact.
• The problem is that it will also try to power anything connected to the wiring of my house, such as the remaining electrical grid in the neighborhood.
• Should a lineman come along to do work on the neighborhood grid, it would be very bad, potentially fatal.
• One way to prevent this powering of the neighborhood grid is to turn off the master breaker where the power grid feeds into my house.
• Another way to prevent this problem is to use a transfer switch to run the power from my genset to the house.

If I got that right, sounds like I should plan to take a transfer switch down with me? Right? And then get a licensed electrician to hook it up?

These may be really basic questions, but I'm fairly ignorant when it comes to electricity. Thanks for the help.

 

Drew,

You pretty much have it down pat. Personally, I'd run a transfer switch - but that may have something to do with an MSEE

 

Thanks for the help. I suspect that electrocuting a lineman would move me to the bottom of the list for reconnection once the power company makes it to my part of the island.

I'll try to find the appropriate transfer switch before I go.

 

No problem. Transfer switches are rated in Amps (as opposed to generators being rated in kilowatts). Take the kW rating of the generator, divide by the voltage - buy the equal (or next larger) ampere rated transfer switch.

Most of my specifications are written around "slightly larger" systems - 480V three phase generators in the 150kW to 2000kW range, transfer switches up to several thousand amps.

Jeff
somewhere in California.........

 

do not plug generator in dryer outlet somewhere near me after fransis or ivan someone did this and failed to turn off the main and KILLED a lineman this was in northen ga near nc line please have a COMPATANT (?) licened insured experienced electrican install a transfer panel or swich so there is no way to power your house from both sources . you must physcaly isolate the generator from the utility . if you back feed the utility the best you can hope for is a burned up genartor when they INTENtionly short it out . and put at the verry bottom of the list to be reconected . the worst is being charged with agervated manslaughter or worse .
Russell NC licensed Electrical contractor

 

The main reason we Parallel generators where I work is for redundancy. If one goes out, the other will pick up the load. Both generators are always the same rating and the total load is never more than what one generator can handle. We also do loadsharing/peak shaving with the public utilities, not so much anymore though. All of our larger generators have sync scopes and loadsharing devices. The big dogs are easy to do... the lil ones are a pain. We have to use an external "box" to link the two together. Getting them in phase is easy, getting them to loadshare and run together is a nightmare. Working on a pair right now, 2 175kw's. Starting almost from scratch, installing current transformers, low voltage trips ect... looking like alot of fun!