Trying to wrap my head around a whole house generator

[churchmouse]

Not sure on depth but avg. frost line comes to mind. Not sure.
Tie in is done on the main lugs so unless you are on an auto start you can do everything manually like we do. Mark the circuits you want to leave engaged.
Turn off everything else including the "MAIN"............Always turn off the main.
You can get a switch gear set up that drops you off the main automatically when power drops. Not seriously spendy.

 

[SSGSAD]

I am going to guess, 18"-24", but this is ONLY, a guess .....

Let us know, what you decide .....

 

[gmcttr]

I use a 5000w portable generator. There is a special receptacle outside to plug it into. The receptacle is wired to a switch box (made for the purpose) mounted next to my main breaker panel. The switches are wired to the main breakers for the furnace (gas so it only has to power the fan and controls), refrigerator and living room and kitchen lights and receptacles. No A/C, no water heater (mine is electric).

This gets me heat, refrigerator/freezer, TV, computer/internet, enough lights and a microwave.

When the power goes out, I drag the generator out the basement door, plug it in and fire it up. Next, is to switch off the main disconnect on the breaker panel so I'm disconnected from the power grid (the linemen will thank you) and turn on the 6 switches, in the added switch box, one at a time to insure starting surges are spaced out slightly.

When power returns, I turn off the 6 switches to isolate the generator, connect the main breaker and power down the generator.

Also, the farther away your barn is, the heavier gage wiring you will need and possibly a larger generator.

FWIW, I'm sold on Honda small engines and paid a premium for a generator that has one. They can sit for years and will start on the first or second pull and are quieter than many competitors.

Make sure you have fuel on hand. With a large power outage, sometimes the close gas stations are also without power and cannot pump gas.

 

[amafrank]

Unlike a lot of tools generators (good ones anyway) are intended to put out the rated load 24/7. That is what the load rating means. Most if not all of them also have a surge load rating which is higher. For example there are some 5KW machines at Lowes which have a 6.5KW surge rating. That means they can handle the extra load when your refrigerator kicks on. Compressors for refrigerators and air conditioners typically pull a lot more juice when starting. They will not supply that extra power for a long time as it will cause overheating or other issues. Thats why its a surge rating. Making more power makes more heat because the machine burns more fuel and it has to dissipate that extra heat. At the normal output rating the machine is capable of getting rid of all the heat it produces while maintaining its integrity. You can put more fuel through the system and make more power but you can't change physics and get rid of the extra heat.

Look up "Generator Coking" to see why running the machinery at 50% instead of 75% is a really bad idea. Most generators are intended to be sized for the load they'll be feeding. If you oversize the gennie you aren't saving anything by running it a lower power settings. You're wearing it out quicker. Running it at lower settings just prevents it from reaching its most efficient power to fuel use range. This means for a given amount of fuel burned it produces less electricity and at the same time the excess fuel is producing carbon buildup inside the cylinder. Over time the carbon buildup on heads and valves slows down heat transfer to the cooling system degrading efficiency further. It also builds up in the exhaust system degrading its ability to flow hot gasses. All in all running it a lower power settings is bad for the engine.

Your 2.5 liter car engine may put out 150 HP at some magic rpm but if you run it at that rpm for very long the engine will blow up or die. It wasn't made to run 100% power for extended periods. It can't dump the heat of that output. A typical car will need about 15-50 HP to run down the freeway at 70mph. All that extra power helps you accelerate but you don't use it often. Ask yourself how often your car engine runs at the redline rpm. So the idea of running at a lower output is valid for some engines and your car or motorcycle are both prime examples. On the other hand generator and stationary pump engines are intended to run at 100% of their rated output for extended periods (airplane engines too for that matter). They do this by various means but usually by derating a larger engine. My 160 HP airplane engine is 320 cubic inches and runs at 2750 rpm redline. That is 5.2 liters and in some car engines that displacement could put out 600HP or more. You may find a 15KW generator plant has an engine with a 2 liter displacement putting out 25hp. They normally run at 1800 or 3600 rpm as well in order to maintain a proper 60 cycle electrical output from the gennie. So no high rpm like your 5500rpm car engine and not putting out the highest HP/displacement.

So back to the beginning. Size your home gennie for the load you actually have and make sure it runs at 65% power or more when it does run in order to get the longest life and best efficiency. If you have a load that drastically changes when your heating or cooling system comes on you're better off running a double gennie system where one generator runs to maintain the primary load and a second comes on when your load jumps up for the secondary. In this way you aren't killing your home power system by underloading it.

Lots of stuff online for gennie sizing and all the other assorted details. Its worth looking into.

Frank

 

[churchmouse]

I use a 5000w portable generator. There is a special receptacle outside to plug it into. The receptacle is wired to a switch box (made for the purpose) mounted next to my main breaker panel. The switches are wired to the main breakers for the furnace (gas so it only has to power the fan and controls), refrigerator and living room and kitchen lights and receptacles. No A/C, no water heater (mine is electric).

This gets me heat, refrigerator/freezer, TV, computer/internet, enough lights and a microwave.

When the power goes out, I drag the generator out the basement door, plug it in and fire it up. Next, is to switch off the main disconnect on the breaker panel so I'm disconnected from the power grid (the linemen will thank you) and turn on the 6 switches, in the added switch box, one at a time to insure starting surges are spaced out slightly.

When power returns, I turn off the 6 switches to isolate the generator, connect the main breaker and power down the generator.

Also, the farther away your barn is, the heavier gage wiring you will need and possibly a larger generator.

FWIW, I'm sold on Honda small engines and paid a premium for a generator that has one. They can sit for years and will start on the first or second pull and are quieter than many competitors.

Make sure you have fuel on hand. With a large power outage, sometimes the close gas stations are also without power and cannot pump gas.

You might want to be careful running a TV on the genny. The power delivered is pretty dirty. For this reason we have 2 small 2 cycle clean power inverted gennys. The terminology might not be correct but they are rated to run power sensitive devices.

 

[Thor]

Truth.

That is why in an extended black out be alert.

That's why the only sounds that identify the prepared won't just be the gen and a/c compressors....there will be the gun fire too.

 

[churchmouse]

Unlike a lot of tools generators (good ones anyway) are intended to put out the rated load 24/7. That is what the load rating means. Most if not all of them also have a surge load rating which is higher. For example there are some 5KW machines at Lowes which have a 6.5KW surge rating. That means they can handle the extra load when your refrigerator kicks on. Compressors for refrigerators and air conditioners typically pull a lot more juice when starting. They will not supply that extra power for a long time as it will cause overheating or other issues. Thats why its a surge rating. Making more power makes more heat because the machine burns more fuel and it has to dissipate that extra heat. At the normal output rating the machine is capable of getting rid of all the heat it produces while maintaining its integrity. You can put more fuel through the system and make more power but you can't change physics and get rid of the extra heat.

Look up "Generator Coking" to see why running the machinery at 50% instead of 75% is a really bad idea. Most generators are intended to be sized for the load they'll be feeding. If you oversize the gennie you aren't saving anything by running it a lower power settings. You're wearing it out quicker. Running it at lower settings just prevents it from reaching its most efficient power to fuel use range. This means for a given amount of fuel burned it produces less electricity and at the same time the excess fuel is producing carbon buildup inside the cylinder. Over time the carbon buildup on heads and valves slows down heat transfer to the cooling system degrading efficiency further. It also builds up in the exhaust system degrading its ability to flow hot gasses. All in all running it a lower power settings is bad for the engine.

Your 2.5 liter car engine may put out 150 HP at some magic rpm but if you run it at that rpm for very long the engine will blow up or die. It wasn't made to run 100% power for extended periods. It can't dump the heat of that output. A typical car will need about 15-50 HP to run down the freeway at 70mph. All that extra power helps you accelerate but you don't use it often. Ask yourself how often your car engine runs at the redline rpm. So the idea of running at a lower output is valid for some engines and your car or motorcycle are both prime examples. On the other hand generator and stationary pump engines are intended to run at 100% of their rated output for extended periods (airplane engines too for that matter). They do this by various means but usually by derating a larger engine. My 160 HP airplane engine is 320 cubic inches and runs at 2750 rpm redline. That is 5.2 liters and in some car engines that displacement could put out 600HP or more. You may find a 15KW generator plant has an engine with a 2 liter displacement putting out 25hp. They normally run at 1800 or 3600 rpm as well in order to maintain a proper 60 cycle electrical output from the gennie. So no high rpm like your 5500rpm car engine and not putting out the highest HP/displacement.

So back to the beginning. Size your home gennie for the load you actually have and make sure it runs at 65% power or more when it does run in order to get the longest life and best efficiency. If you have a load that drastically changes when your heating or cooling system comes on you're better off running a double gennie system where one generator runs to maintain the primary load and a second comes on when your load jumps up for the secondary. In this way you aren't killing your home power system by underloading it.

Lots of stuff online for gennie sizing and all the other assorted details. Its worth looking into.

Frank

Interesting stuff but not true of all Generators.
Some maybe but not all of them.
I just pulled 2 of mine out and the Emblazoned rating on the fuel tanks are full inrush not steady load. The rating plate verified this.
I am wondering if there is a standard in that industry as to advertised loads.

 

[churchmouse]

That's why the only sounds that identify the prepared won't just be the gen and a/c compressors....there will be the gun fire too.

Exactly.

 

[Tom Threetoes]

I just had my garage wired and the electrician had me trench the leads 24 inches deep so I assumed that was code.