Not overloading the generator

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swimmer_spe

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I moved to this house about 2 months ago. It came with a 11,500 watt generator. I know it runs, and runs well. They had run several power cords around the basement to the important things (sewage sump pumps, fresh water pump and heat tracing, and furnace). I am trying to figure out what more can be added without overloading the generator. Can the fridge or freezer be added? I do plan to have some lamps plugged in as needed.
 

Snoonyb

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It's pretty basic; all elec. appliances have a "operating wattage" listed somewhere on their nomenclature package, that wattage, divided by the appliances "operating voltage" will give you the current consumption, in amps.

11,500W divided by 240V equals 47.916 Amps
11,500W divided by 120V equals 95.833 Amps

Prudent use would reduce those by 20%.
 

swimmer_spe

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It's pretty basic; all elec. appliances have a "operating wattage" listed somewhere on their nomenclature package, that wattage, divided by the appliances "operating voltage" will give you the current consumption, in amps.

11,500W divided by 240V equals 47.916 Amps
11,500W divided by 120V equals 95.833 Amps

Prudent use would reduce those by 20%.
Fortunately, nothing is 240V. It's all 110V. So, I can figure about 80 Amps? That is actually a lot more than I thought.
Now to figure out the operating wattage of each thing already to be plugged in.
 

Snoonyb

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Some of the information may need to be ascertained by conducting a model search, as opposed to finding nomenclature tags.
 

Sparky617

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Keep in mind, your fridge and freezer don't need to run all the time nor do they run all the time. Especially with a chest freezer if you keep it closed you can unplug it and run it every couple of hours. Same with the fridge. If you have electric heat, an electric water heater, electric dryer, electric range, central air you'll need to make sure that you don't several of those at a time. Your water heater will keep water hot for hours without running. I had time of day service in my first house and only heated water during off-peak hours. I never ran out of hot water if we were careful. If you've moved to LED lights your lighting load will be very small, not that it is a huge part of your electric use to begin with. Newer flat panel TVs use less electricity than picture tube models from 15 years ago. Plasma TVs use more than LED.
 

swimmer_spe

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Keep in mind, your fridge and freezer don't need to run all the time nor do they run all the time. Especially with a chest freezer if you keep it closed you can unplug it and run it every couple of hours. Same with the fridge. If you have electric heat, an electric water heater, electric dryer, electric range, central air you'll need to make sure that you don't several of those at a time. Your water heater will keep water hot for hours without running. I had time of day service in my first house and only heated water during off-peak hours. I never ran out of hot water if we were careful. If you've moved to LED lights your lighting load will be very small, not that it is a huge part of your electric use to begin with. Newer flat panel TVs use less electricity than picture tube models from 15 years ago. Plasma TVs use more than LED.
Heat is with propane forced air.
Besides a few lights, the only other thing would be the fridge or freezer. Realistically, if it is only a few hours, I'm not worried about it. I am more worried if it lasts more than 12 hours.
 

Eddie_T

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I use a 5000 watt generator connected to the panel through a 240 receptacle. I need 240v for my well pump and it's handy to be able to use any house circuit if needed. I load manage the heavy loads by flipping breakers as needed, the rest by their respective switches. During the daytime I only run the generator periodically to keep fridge and freezer boxes cold and when I need to pressurize the well water tank. I haven't tried the electric water heater, I might during a long outage.

I am thinking of a battery operated inverter power station to run my WiFi and computer for news and entertainment but am still procrastinating. So far I have computer and TV only when I am running the generator for other needs. At night I run it for around four to five hours anyway to ensure that the fridge and freezer are cold enough to go overnight. My Coleman generator does not have an inverter so its native output is a true sine wave.
 

Bob Reynolds

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11,500 watts will run a lot of things and should allow you to stay in your house during an extended power outage. I would not run any high usage items (electric dryer, dishwasher heat cycle, electric oven, etc., unless everything thing else was off. Those are 4500 watt items.

The HVAC motors do use a lot of power to start up. So if you have more than one HVAC system you are going to want to start those one at a time after the generator is up an running. Once they are running, you should be ok to let them all run at the same time. Electric heat strips are not going to work well with a generator and you will not be able to use them unless everything else is off. Propane or natural gas will be fine, just be aware of the motor start up surge.

If you have a septic tank pump, that also uses a lot of power to start. You will want to turn that off while the power is out. Turn it on the the afternoon when most everything else is off and let it pump out your holding tank for a few minutes then turn it off again.

The well pump uses more power on start up, but it is generally ok to leave it on unless it is bogging down the generator. If the pump is running well, then you should not have a problem. If you do just turn it off until you need it. Your pressure tank will hold enough water to wash your hands, flush the john, etc.

Refrigerators and freezers, that are running properly, can generally stay connected because they don't run all the time.

When there is an outage in our area, our generator stays on continuously. It is connected to the house wiring system though a disconnect switch installed by the electrician. He has color coded the switches green that need to be on during a power outage and color coded the switches red (including the main) that need to be off during the power outage.

I shut the generator down in the afternoon during the highest temperature of the day (usually around 4) and I change the oil. I do this every day the generator is running. Make sure you have oil on hand to do this. When the outage is over, I turn the fuel supply off and let it run out of gas so it will not gum up the fuel intake system. If you do this, your generator will last you for many years (probably decades) and will be ready when you need it.

Lights are a non issue because they don't use much power these days. I would just leave any halogens or bulbs that use over 60 watts off. Hopefully you have replaced your bulbs with LED's.

Televisions these days don't use much power so you should be ok with those.

Hope this helps.
 

swimmer_spe

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11,500 watts will run a lot of things and should allow you to stay in your house during an extended power outage. I would not run any high usage items (electric dryer, dishwasher heat cycle, electric oven, etc., unless everything thing else was off. Those are 4500 watt items.

The HVAC motors do use a lot of power to start up. So if you have more than one HVAC system you are going to want to start those one at a time after the generator is up an running. Once they are running, you should be ok to let them all run at the same time. Electric heat strips are not going to work well with a generator and you will not be able to use them unless everything else is off. Propane or natural gas will be fine, just be aware of the motor start up surge.

If you have a septic tank pump, that also uses a lot of power to start. You will want to turn that off while the power is out. Turn it on the the afternoon when most everything else is off and let it pump out your holding tank for a few minutes then turn it off again.

The well pump uses more power on start up, but it is generally ok to leave it on unless it is bogging down the generator. If the pump is running well, then you should not have a problem. If you do just turn it off until you need it. Your pressure tank will hold enough water to wash your hands, flush the john, etc.

Refrigerators and freezers, that are running properly, can generally stay connected because they don't run all the time.

When there is an outage in our area, our generator stays on continuously. It is connected to the house wiring system though a disconnect switch installed by the electrician. He has color coded the switches green that need to be on during a power outage and color coded the switches red (including the main) that need to be off during the power outage.

I shut the generator down in the afternoon during the highest temperature of the day (usually around 4) and I change the oil. I do this every day the generator is running. Make sure you have oil on hand to do this. When the outage is over, I turn the fuel supply off and let it run out of gas so it will not gum up the fuel intake system. If you do this, your generator will last you for many years (probably decades) and will be ready when you need it.

Lights are a non issue because they don't use much power these days. I would just leave any halogens or bulbs that use over 60 watts off. Hopefully you have replaced your bulbs with LED's.

Televisions these days don't use much power so you should be ok with those.

Hope this helps.
The sumps are quite small. Sounds like I should be getting a bigger one as the current one can only take about 2 flushes of the toilet before it pumps out.
 

68bucks

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The sumps are quite small. Sounds like I should be getting a bigger one as the current one can only take about 2 flushes of the toilet before it pumps out.
Is the generator a whole house standby type? Just curious 11.5 kw is a good sized generator.
 

swimmer_spe

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Is the generator a whole house standby type? Just curious 11.5 kw is a good sized generator.
No. It is a portable one that the former owners bought and setup to run vital systems, especially in winter. Within about 5 minutes; the generator is running, heat is supplied to the house and the waterline, and we can use water as needed, including flushing the toilets.
 

BuzzLOL

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I moved to this house about 2 months ago. It came with a 11,500 watt generator. I know it runs, and runs well. They had run several power cords around the basement to the important things (sewage sump pumps, fresh water pump and heat tracing, and furnace). I am trying to figure out what more can be added without overloading the generator. Can the fridge or freezer be added? I do plan to have some lamps plugged in as needed.
Hopefully, the generator is outside and not running in the basement.
Wonder why they ran "several cords", 11,500 watts should run the entire house under most, if not all, conditions. I would have just run a heavy cord to the main power box with a heavy duty switch box to switch from generator or utility power. Turning off the utility mains before switching to generator power.
 

swimmer_spe

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Hopefully, the generator is outside and not running in the basement.
Wonder why they ran "several cords", 11,500 watts should run the entire house under most, if not all, conditions. I would have just run a heavy cord to the main power box with a heavy duty switch box to switch from generator or utility power. Turning off the utility mains before switching to generator power.
Yup, it is outside. There is a roof over it to keep the weather off of it, but it is not enclosed.

They likely did it to save money. I do have plans to eventually wire it to the main panel. I know it will be a higher cost to do it, but in the end, it will be good overall.
 

Eddie_T

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I guess I broke all the rules but here I am 20 yrs later. I didn't break in my generator, I figured my loads were light enough to serves as break in. Also I don't do frequent oil changes since it isn't used very often. If I had frequent outages I would probably get a small generator for lights and electronics and just use the 5Kw unit for the well pump and fridge/freezer boxes if the smaller one wouldn't handle them.

It's not cost effective to switch over to an inverter generator but the lower rpms and better fuel economy would be nice. Plus I think I could get by with a 120v 3.5Kw unit and an autotransformer to feed my panel with 240v.
 

swimmer_spe

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I guess I broke all the rules but here I am 20 yrs later. I didn't break in my generator, I figured my loads were light enough to serves as break in. Also I don't do frequent oil changes since it isn't used very often. If I had frequent outages I would probably get a small generator for lights and electronics and just use the 5Kw unit for the well pump and fridge/freezer boxes if the smaller one wouldn't handle them.

It's not cost effective to switch over to an inverter generator but the lower rpms and better fuel economy would be nice. Plus I think I could get by with a 120v 3.5Kw unit and an autotransformer to feed my panel with 240v.
If the house didn't come with it, I might not even worry about it as the power grid is fairly stable out here. In the spring, I'll change the oil and run it for an hour without a load. However, having it has me thinking about somehow getting it tied into the panel so that there is no messing with power cords. As I understand it, if the power goes out, you will hear lots of generators running.
 

Eddie_T

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I don't recommend my approach for everyone but I installed a 240v receptacle on the inside front wall of my garage and use a male to male jumper cord to connect the generator to the receptacle so that one cord is all that's needed. I have a lockout that I put on the main breaker that has to be removed to flip the breaker on. I just added the lockout this year in case someone gets nosey while my garage door is open. But I have had utility workers on my property when the problem was in my high voltage underground feed and they showed zero concern regarding my generator.
 

ekrig

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Wonder why they ran "several cords", 11,500 watts should run the entire house under most, if not all, conditions. I would have just run a heavy cord to the main power box with a heavy duty switch box to switch from generator or utility power. Turning off the utility mains before switching to generator power.
They likely did it to save money. I do have plans to eventually wire it to the main panel. I know it will be a higher cost to do it, but in the end, it will be good overall.
Keep in mind that 11.5kW is a lot of power to run through only one cord. Even a pretty beefy one will likely take a max of 30amps, and that's only about a third of the generator's power at 110VAC.
 

swimmer_spe

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Keep in mind that 11.5kW is a lot of power to run through only one cord. Even a pretty beefy one will likely take a max of 30amps, and that's only about a third of the generator's power at 110VAC.
The "save money" part is the fact that they ran extension cords all over instead of having them all go to the panel.
 

Jeff Handy

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I don't recommend my approach for everyone but I installed a 240v receptacle on the inside front wall of my garage and use a male to male jumper cord to connect the generator to the receptacle so that one cord is all that's needed. I have a lockout that I put on the main breaker that has to be removed to flip the breaker on. I just added the lockout this year in case someone gets nosey while my garage door is open. But I have had utility workers on my property when the problem was in my high voltage underground feed and they showed zero concern regarding my generator.
Using a cord with male plugs on both ends is very dangerous, even though I have done it myself.

It is known as a “suicide cord” because when you plug one end into the running generator, the exposed prongs on the other end are live current and unprotected.

I always killed the service panel main breaker first, to avoid back feeding out to the pole.
Then plugged both male ends in first, then started the generator, then flipped the breaker in my garage sub panel to feed back to the house.

My home’s previous owner had installed a 240 volt welding outlet in the garage, which is how I plugged in the other male cord end.

I had a written checklist hanging on my main panel, to remind me of this safety procedure in an emergency.

I would alternate heavy loads by flipping individual breakers.

Big motors can use twice their rated amps for a few seconds, when starting up.

Electronic circuits like tv or computer can be damaged by a generator without a true sine wave output.

Even appliances like a modern refrigerator with a circuit board controller can be fried, you never know how they will handle it.
But they usually are ok, just be warned.

It is much safer to install a generator socket to plug in your generator to the house.

The generator socket is like a male prong receptacle, in a deep recessed housing.

So you can safely plug into it with the female end of your generator cord.
 

Eddie_T

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Fortunately, nothing is 240V. It's all 110V. So, I can figure about 80 Amps? That is actually a lot more than I thought.
Now to figure out the operating wattage of each thing already to be plugged in.
Look up the specs for your generator, as a 240V machine it has a max amperage that is not to be exceeded. That amperage does not go up just because you are using 120V loads.

The 120V circuits are essentially branch circuits and shouldn't all be on the same leg of the 240V. Some neutral currents will cancel at the generator receptacle panel and those loads will be seen as 240V by the winding. If it has four 120v receptacles (two on each leg) the loads will have to be divided such that the maximum amperage at any individual receptacle or the sum of the four does not exceed the generator current rating.
 

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