# backup generator



## HuntingHawk (Dec 16, 2012)

First I want to explain that generators are rated in watts but appliances are probably rated in amps. 
Always make sure on a generator listing that you are looking at run wattage versus surge wattage.

So, to figure the amperage a generator will provide you divide the wattage by the voltage. a 4000watt generator would be 4000 divided by 120(voltage) or 33amps maximum.

On the other hand, to figure the wattage of an appliance you know the amperage of you multiply voltage times amperage. So a 9.6amp air conditioner I have would be 9.6 times 120 equal 1152watts.

Never figure you can get by with minimum size generator. 

As for myself, I need 240VAC for my well pump so got a 5500watt generator in 2003 & has a 30amp 240VAC plug. Can't run everything in the house at the same time but don't have to. Generator saved my butt from the 2004 hurricanes. Also nice that it will power my arc welder.


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## rjd25 (Nov 27, 2014)

HuntingHawk said:


> First I want to explain that generators are rated in watts but appliances are probably rated in amps.
> Always make sure on a generator listing that you are looking at run wattage versus surge wattage.
> 
> So, to figure the amperage a generator will provide you divide the wattage by the voltage. a 4000watt generator would be 4000 divided by 120(voltage) or 33amps maximum.
> ...


Also keep in mind your amperage will be limited by the weakest link in the system. For example, if your wire from your generator to the transfer switch is 10 gauge the maximum amperage rating for that wire would be 30 amps only. If you hook up a 9000 watt generator to a circuit with 10 gauge wire and a 100 amp breaker you are asking for an electrical fire.


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## Smitty901 (Nov 16, 2012)

I though you just kept plugging things in until the cord got hot then unplug a couple. Joking, you make a good point. We have 3 and use only what is needed if the power goes out. Another thing to remember is isolate any thing you are running on a generator from the grid, you could kill a repair worker.


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## paraquack (Mar 1, 2013)

Thanks Smitty901. Too many times uneducated "electricians" think they can just run the generator feed into their fuse/circuit breaker panel and run what ever they need to. Not think that the generator will be sending power down the line to whee that unsuspecting repair worker is handling wires knowing they're dead. OPPS. Happened in ILL during a tornado disaster.


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## rjd25 (Nov 27, 2014)

paraquack said:


> Thanks Smitty901. Too many times uneducated "electricians" think they can just run the generator feed into their fuse/circuit breaker panel and run what ever they need to. Not think that the generator will be sending power down the line to whee that unsuspecting repair worker is handling wires knowing they're dead. OPPS. Happened in ILL during a tornado disaster.


I am pretty sure it is illegal in most places to back feed into the grid. Most places require either a transfer switch or an interlock device be installed which would only allow the generator to power your panel if the main breaker is in the off position. People don't realize when your little generator runs back through the transformer on the pole the voltage gets stepped back up considerably and you really can kill a linesman who thinks the power is off.


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## paraquack (Mar 1, 2013)

You are correct hence the term *"uneducated electricians"* referring to the home owner who is uneducated or the neighbor who knows how put a wire under a screw and think they are an electrician.


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## HuntingHawk (Dec 16, 2012)

I don't touch my breaker panel.

My normal largest load is a 15,000BTU AC. Where I put the generator the AC gets directly plugged into it. Everything else is via extension cord & time shared.

But I do have to roll the generator out to the pump house every morning to run the well pump.


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## paraquack (Mar 1, 2013)

I've seen some unique ways of wiring a home to make it compatible for a generator. While extension cords may not be the easiest, I feel it is the safest for the home electrician. In my new house down here in AZ, I was amazed to find the normal way for a furnace to be wired to the home was thru a standard 120 volt, 15 Amp 3 prong grounded plug. Al I have to do is pull out of the outlet and connect to the generator I don't have yet. But I'm working on it.


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## rjd25 (Nov 27, 2014)

paraquack said:


> I've seen some unique ways of wiring a home to make it compatible for a generator. While extension cords may not be the easiest, I feel it is the safest for the home electrician. In my new house down here in AZ, I was amazed to find the normal way for a furnace to be wired to the home was thru a standard 120 volt, 15 Amp 3 prong grounded plug. Al I have to do is pull out of the outlet and connect to the generator I don't have yet. But I'm working on it.


I use a 3 prong 240 volt outlet that is usually powering my pool pump. The problem is as I described above, it is a 30 amp circuit with 10 AWG wire which limits me to 30 amps of draw for my panel. I use what is called a "suicide plug" to connect it... LOL


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## GTGallop (Nov 11, 2012)

HuntingHawk said:


> First I want to explain that generators are rated in watts but appliances are probably rated in amps.
> Always make sure on a generator listing that you are looking at run wattage versus surge wattage.
> 
> So, to figure the amperage a generator will provide you divide the wattage by the voltage. a 4000watt generator would be 4000 divided by 120(voltage) or 33amps maximum.
> ...


Knowing that math and cognitive skills will be grossly compromised when the SHTF, I have taken the liberty of doing the math and putting labels on all of my gear that I will want to run and on my inverters


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## HuntingHawk (Dec 16, 2012)

Remember when filling gas cans to set them on the ground. Eliminates chance of static electricity.


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## HuntingHawk (Dec 16, 2012)

After several hours of research I'm thinking dual fuel gasoline/LPG would work best for me. Being I already have several good 20lb bottles plus some older ones that can be swapped out. Use gasoline as long as it can be had & then LP after that.


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## bigwheel (Sep 22, 2014)

Where are we going to get the fuel to run the biotch and keep it fresh till the zombies and/or space aliens attack? Yall tend to drive me crazy sometimes.


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## alterego (Jan 27, 2013)

bigwheel said:


> Where are we going to get the fuel to run the biotch and keep it fresh till the zombies and/or space aliens attack? Yall tend to drive me crazy sometimes.


My generator burns about a gallon per hour. To keep things similar to running on the power company we run the generator for an hour in the morning and from 6 to 8 at night. So three hours a day. Equals three gallons of gas per day. This is enough to keep the house warm. The freezer full and the cow tank full of water. We currently are almost without gas storage at my home. Shamefully given gas is 2.93 per gallon not far away.


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## rjd25 (Nov 27, 2014)

bigwheel said:


> Where are we going to get the fuel to run the biotch and keep it fresh till the zombies and/or space aliens attack? Yall tend to drive me crazy sometimes.


This is how you power your generator in a SHTF scenario...


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## Moonshinedave (Mar 28, 2013)

There are many many places online that will give you a chart of the typical draw of each appliance you want to run and how big of generator you will probably need. Just search for* generator load chart*.
I have a 8000 watt running 13,500 watt starting generator, which will run all that I have, except for the central AC., Note that I have a gas furnace, and a gas hot water tank.


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## HuntingHawk (Dec 16, 2012)

For over 10 years I've been telling people that say they can't afford a generator that they can afford to loose a few hundred dollars worth of food though.


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## rickkyw1720pf (Nov 17, 2012)

Unfortunately you can not just compare the watts a generator puts out with the watts an appliance uses. Usually you are getting running wattage of an appliance. Anything with a motor requires a lot higher starting current. Now a lot of generators will have the ability to supply a much heaver current for a shot time to make up for this but you better check before you buy.


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## HuntingHawk (Dec 16, 2012)

That is why a generator has rated running watts & separate rating for surge watts.


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## alterego (Jan 27, 2013)

rjd25 said:


> This is how you power your generator in a SHTF scenario...


I wonder why you could not run off the exhaust of a wood furnace after you get a bed of coals and you shut the damper. The smoke that comes off is consistent.


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## rjd25 (Nov 27, 2014)

alterego said:


> I wonder why you could not run off the exhaust of a wood furnace after you get a bed of coals and you shut the damper. The smoke that comes off is consistent.


it would most likely burn but without the filtration you would tar the shit out of your engine until it died.


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## tinkerhell (Oct 8, 2014)

I have a 4000watt generator, rather than take chances with it connected to my breaker box, I've got an extension cord and a powerbar that will allow me to run the freezer and charge some electronics. Much better than killing a line worker by accident.
Besides, if I stay connected to the grid, I will know when the power comes back (assuming that its just a winter storm power outage)


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## rjd25 (Nov 27, 2014)

tinkerhell said:


> I have a 4000watt generator, rather than take chances with it connected to my breaker box, I've got an extension cord and a powerbar that will allow me to run the freezer and charge some electronics. Much better than killing a line worker by accident.
> Besides, if I stay connected to the grid, I will know when the power comes back (assuming that its just a winter storm power outage)


Extension cords are problematic because you have to leave a door or window open to run the cord to the generator, also you have no lights which sucks. If you want to know when the power is back on just look at your street lol when the houses near you who haven't prepared are lit up once again you will know the power is back on. If you aren't comfortable call an electrician to put in a generator connect.


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## Moonshinedave (Mar 28, 2013)

Turning the main feed breaker off before back feeding into the breaker box is a must, and will keep from injury to a electrical worker. I just unplug the 220v dryer and plug the generator in *after turning off the main breaker* of course. I have a digital watt meter, when it's blank, electricity is still off, when it can be read, power back on.


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## rjd25 (Nov 27, 2014)

Moonshinedave said:


> Turning the main feed breaker off before back feeding into the breaker box is a must, and will keep from injury to a electrical worker. I just unplug the 220v dryer and plug the generator in *after turning off the main breaker* of course. I have a digital watt meter, when it's blank, electricity is still off, when it can be read, power back on.


The problem is when the husband leaves and the wife or young adult is left to start the generator or switch it back over to grid power. You should really get one of these so that both the main and generator power cannot be in the "on" position at the same time. It takes 5 minutes to install and two screws total for 100% peace of mind.

http://i.stack.imgur.com/XiLFQ.jpg


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## HuntingHawk (Dec 16, 2012)

I run the extension cords threw a window & lay a strip of weather stripping & then close the window as far as possible.


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## tinkerhell (Oct 8, 2014)

rjd25 said:


> Extension cords are problematic because you have to leave a door or window open to run the cord to the generator, also you have no lights which sucks. If you want to know when the power is back on just look at your street lol when the houses near you who haven't prepared are lit up once again you will know the power is back on. If you aren't comfortable call an electrician to put in a generator connect.


Oh, I'm very comfortable doing the work myself. I've worked in the electrical field long enough to know all I have to do is flip the main breaker(disconnect from the grid) and I have an outlet near the breaker box that is about the same as what my generator is.

Ureka! I have have the entire house powered from a 4000Watt generator. This is both a blessing and a curse. I have the perfect weapon for over-working my generator and the impossible task of training my family to be wise on how many appliances and lights are turned on at 1 time. Believe me, it is better to have an extension cord and a power bar. You can control exactly what gets plugged in and turned on.

Just my opinion. I won't fault anyone for having their own. We all have different capabilities and different priorities. Best of wishes to you.


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## Mad Trapper (Feb 12, 2014)

tinkerhell said:


> Oh, I'm very comfortable doing the work myself. I've worked in the electrical field long enough to know all I have to do is flip the main breaker(disconnect from the grid) and I have an outlet near the breaker box that is about the same as what my generator is.
> 
> Ureka! I have have the entire house powered from a 4000Watt generator. This is both a blessing and a curse. I have the perfect weapon for over-working my generator and the impossible task of training my family to be wise on how many appliances and lights are turned on at 1 time. Believe me, it is better to have an extension cord and a power bar. You can control exactly what gets plugged in and turned on.
> 
> Just my opinion. I won't fault anyone for having their own. We all have different capabilities and different priorities. Best of wishes to you.


You can regulate what gets used by using the breakers in the panel. E.g. If you need to run the well pump all else should be off. When you have enough water and the tank is fully pressurized, you flip that breaker and turn on things like lights and the frig.

You can also have your battery bank connected to a 120V charger so if the genny is not using near full output some of the rest is stored in DC that you can use later with the genny off


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