Portable Home Generator Questions

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After last month's ice storm in North Carolina, I have decided to invest in a portable generator. After some research at various sites, I am certain that around 8 kw will fit my needs. However, I still have **many** very basic questions about generator types, fuel storage, fuel consumption, power cabling to the transfer switch, etc.
I know there are a lot of questions, and hopefully folks will comment or advise on the ones about which they have knowledge or experience.
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In terms of efficiency and fuel use, which generator type is best..... gas, diesel, or propane ?
Has anyone here used a tri-fuel generator, such as the one made by Northern Industrial Tools ?
How can one safely and properly store 150 gallons of gas ? I figure this is the maximum amount that i would need in any severe storm. I am aware of the use of Stabil, and I would also "rotate" the gas at least once a year.
Has anyone here used a propane generator ? If so, how well did you like it ? What model have you used ? If you have not used one, do you know of one on the market right now, in the 8 KW range ? (I find that all the propane ones I find are much larger generators, up to 12-15 kw or higher).
In terms of fuel usage, is a gallon of propane about the same as a gallon of gas ?
I need 6 120 volt circuits, and two 240 circuits. The 240 circuits are needed for hot water, and water pump. Will this mean that I will need 3 distinct power cables run from my generator to the transfer switch in the house ? Are these pre-manufactured cables in given lengths, or will my electrician custom make cables ??
If I use a propane tank, it may well be 50 feet lower in elevation than my generator, and up to 100 feet away. Will the propane travel an uphill run like this ?
What is your favorite generator in the 7-8 KW range ?
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Well, that should be enough questions for now !!
Thank you in advance for any comment or advice !!
James
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As far as the transfer switch and cord, the units generally come with twist lok outlets up to 50 amps. You can buy these pre built, or built to whatever length you like. You typically run one cord from the generator to a manual transfer switch
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RBM, thank you for the good comments !! I am looking for a portable generator, as the is the price class that I am in. I will have a transfer switch installed by a qualified electrician, but it will not be automatically engaged. If we lost power, I will start the generator and flip the transfer switch.
As to the power cord, I am confused......... on the units I have seen, they have one or more 120 volt outlets, and most have one or two 240 volt outlets..... I would not need cords for each of these outlets ??
Very good comments/comparisons of gas, diesel, and propane.
Thanks again !!
James
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On the larger portable units they'll typically have multiple outlets. Some standard 120 volt 20 amp, some 120/240 volt 30 amp, and in your case you'd want one that has a 120/240 volt 50 amp. You would buy a transfer switch that would be fed through a 50 amp 4 wire cord, providing both 120 volt and 240 volts to the switch. There is no need to use any additional cords.
Another thing to note: portable units typically have fairly small fuel tanks, often holding less fuel than you'd need to go through the night. Check the fuel consumption at full load and at half load, then do a calculation to determine if it's big enough for your needs. You can always use a fuel tank, not attached to the unit, but it becomes less portable, and potentially more dangerous.

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Thanks again to all/ good site Dennis/ good comments CY.
James
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No, in a semi-pernanent installation you will have something like this next to your main breaker panel
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200321033_200321033
you only need one big 240VAC cord to make this work. sized for the total load that will be on the generator.
nate
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The transfer switch that Nate links to is probably the cheapest, easiest method of connecting a generator to your electric service, and won't take an electrician more than an hour to connect. Note: the one shown has a thirty amp twist lok

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When you have a transfer switch installed, you run one cable to the generator. It will usually have 4 wires in it and they will all go into the 240 volt plug. The older unit will have a 3 wire plug. Two of the wires will be to the hot wires, one to the neutral, and the other one if used will be a chassies ground. The power will be split as needed at the box at the house.
Diesel will probably be the best. It lasts for many years unlike gas. Also you will probably want to run the generator for short periods of time every couple of weeks or so. Gas tends to wash the oil from the piston rings and get into the crankcase oil during the short run periods.
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Can't say as I've ever heard that.
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On Fri, 22 Jan 2010 19:23:36 -0500, "Stormin Mormon"
It can happen, if the engine is not allowed to fully warm up during the test runs. Diesels can also 'cold stack' if run without a load for an extended period of time. (some are more prone to doing this than others, but generally any emergency generator should be run under load when exercising it, to ensure that the entire system works properly).
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On Fri, 22 Jan 2010 19:23:36 -0500, "Stormin Mormon"
Particularly true of engines that do not get up to full operating temperature.
Propane, being a "dry gas" does not have this problem. Nor does CNG.
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On Sat, 23 Jan 2010 16:37:38 -0500, snipped-for-privacy@snyder.on.ca wrote:

Diesel engines are so efficient that at unloaded idle they barely get warm. I've got engines that you can touch the exhaust manifold if they have only been idling, even 10 minutes after starting. (pretty amazing).

True...
Best fix is simply to make sure the generator is loaded during exercising runs. The rule that I have is the run is 45 minutes, 15 minutes pre-online to get warmed up some, and to allow checking of everything, then 30 minutes full load (or as close as I can get to full load). Then a proper shutdown, and I'm set for the next exercise run (or next power failure!)
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Stormin Mormon wrote:

When you exercise a stationary generator, you want to run it long enough to boil away any raw gas or water that may be in the system. I installed quite a few Generac air and liquid cooled generators. My favorites are the 1800rpm liquid cooled units instead of the 3600rpm screamers which are either air or liquid cooled. Raw gas is not a problem with NG or LPG but moisture buildup in the exhaust system and crankcase can cause problems. Getting the whole thing warm tends to drive moisture out of every little nook and cranny which will help prevent corrosion of fasteners, electrical components and windings. One of the most vexing problems involved dirt/mud daubers building nests in every 1/4" opening on a generator especially vent tubes for the gas pressure regulators. This is solved by pinching the end of the tube down until it looks like a double barreled shotgun. Use it or lose it.
TDD
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For portable, you're likely limited to gasoline.
One cord will handle 120 and 240 volts, both. Your electrician can do this.
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wrote Re Portable Home Generator Questions:

Diesel.
No experience with that.

I store 30 gals in an old chicken coop located 350' from my house. I live in a rural area with no applicable building codes for such storage. I use six 5-gal gas cans which I rotate: 1 can about every six months. I use Stabilt and rotate the gas into my truck. During a prolonged outage I use about 5-gals per day to run the freezer, fridge, some basic lights, and the natural gas forced air heating system. My generator is a 5Kw unit that is too small to power much more than that.

As I recall, a kg of propane has slightly more energy content than a kg of gasoline.

The propane will travel as a vapor so it will travel up the 50' elevation.
--
Work is the curse of the drinking class.

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-snip-

No- propane is heavier than air, so it puddles like [invisible] water.
Jim
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Except that it is under pressure in the tank, so that it will run up hill.
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wrote:

Guess I'm having a senior moment. I saw vapor and was thinking the OP was worried about leakage. I stand corrected- but I would check on piping propane 100 feet.
Jim
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If water is heavier than air, why do second floors of houses have showers and toilets?
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On Fri, 22 Jan 2010 19:22:31 -0500, "Stormin Mormon"

Propane is heavier than air, while natural gas is slightly lighter and disperses widely.
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