Basic portable generator questions

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  #1  
Old 01-25-15, 09:27 PM
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Basic portable generator questions

I'm installing an interlock kit for a portable generator hookup. The interlock install is purely for convenience, I'm going to strictly monitor wattage use.

I need to now buy a portable generator.
I only want to power the basics:
  • Fridge
  • Boiler (oil)
  • Lights
  • Microwave
  • TV/DVD/Xbox
  • Window A/C unit

Again, I'm going to strictly monitor wattage use. So if I need to run the boiler, I'll probably kill the fridge. If I need to use the microwave, I'll kill the TV first. And so on.
  1. Would a 4K watt generator be sufficient?
  2. Is it ok to power these devices directly from a generator? Do I need some sort of regulator between the generator and the device? If so, which devices would this apply to. (e.g. "clean" vs "dirty" power)

Ideally, I want to spend as little money on this as possible. I'm not interested in some elaborate setup. Just something to keep the heat/AC running along with a few lights. If I have to forgo the entertainment entities, so be it.
 
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  #2  
Old 01-25-15, 09:39 PM
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I guess the generator that you want is powered by gasoline. If so, consider the noise factor & the gasoline storage. Gas doesn't last long in those things & they are very noisy. A generator powered by propane or natural gas would be a better idea. Calculate the power each of your appliances use. That will tell you if the generator is sufficient.
 
  #3  
Old 01-26-15, 05:06 AM
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Saying you'll forgo the entertainment stuff is little issue. TV's and a few lights don't pull much current so your generators size will be dictated by the big items like the AC, starting the fridges compressor and running the microwave. Get a generator to handle those loads and you'll be able to do a lot of other things when one of the big ones is not running. You also need to decide if you want to be able to run one of your big items at a time or all simultaneously.

Unfortunately everyone says they don't want to spend much money... So, what is your budget? You will get what you pay for. There are some cheap imported generators that can do what you want but it's sorta the luck of the draw. If you get a good one it might be good for years. Many are Chinese imports with any number of brand names slapped on them so parts and support can be a problem. A brand name generator especially with a Honda engine will cost more but you will be able to find someone to work on it and parts will be available. Many will run on multiple fuels. Propane would be best if you already have a large tank but you can also run them off small, portable tanks.
 
  #4  
Old 01-26-15, 05:18 AM
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You can safely say that no regulator sold separately is needed when using a generator. You just plug in the lights and appliances you wish to use (subject to total wattage needed) and turn on the generator. (The generator's own main switch or breaker should be off at the moment of startup.) If it needed an add on regulator, the generator is unfit for consumer use and probably did not pass safety guidelines such as from Underwriters Labs.

(The generator has or should have circuit breakers or other overcurrent devices built in.)

You might consider a transfer switch unit that has several small transfer switches instead of one large transfer switch. You install this next to the breaker panel or wherever its supplied flexible conduit with wiring will reach the breaker panel. The branch circuits with your essential loads are wired into the switch unit using the wiring supplied and perhaps a few extensions (pigtails) in the breaker pandl if the wires don't reach.
 
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Old 01-26-15, 07:01 AM
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Lowest cost option is to install a single circuit transfer switch for the boiler and get a long extension cord for anything else you want to run. For running any one of those things at a time a very small generator would likely be ok like a quiet Honda 2kw.
 
  #6  
Old 01-26-15, 08:08 AM
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4kw is probably enough, if the window A/C is not over 10,000 (and 120v) and you have hot water/steam boiler (no air handler fan). The TV is not a problem if LCD - check watts if CRT or Plasma. Refrigerator runs about 2-300 watts and spikes to about 1000wats on compressor start. With that smaller size and a larger A/C you might best turn off A/C while using the microwave. There is not much price difference to get 6kw or so and all of those items would run together.

All that said - Are interlocks legal in your jurisdiction? Is your proposed interlock listed for your panel? Are you going to get a permit for the installation of your inlet and interlock?
 
  #7  
Old 01-26-15, 03:33 PM
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A generator powered by propane or natural gas would be a better idea.
Can I use a standard propane tank (e.g. one used for grilling) to power such a generator? And how long would a single tank last? Are we talking hours or days?

Unfortunately, I don't have natural gas in my area.
 
  #8  
Old 01-26-15, 03:41 PM
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You can safely say that no regulator sold separately is needed when using a generator.
Are you saying I can run any common household appliance directly off a generator? I'm reading otherwise from various google'd articles but I don't know if they are mostly fear-based campaigns.

You might consider a transfer switch unit that has several small transfer switches instead of one large transfer switch.
I did the pro and cons of this and an Inter-lock kit seems far superior:
  • Cheaper
  • Supplies power to all circuits
  • Easier to install
 
  #9  
Old 01-26-15, 03:44 PM
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There is not much price difference to get 6kw or so and all of those items would run together.
I disagree. I can get a well-reviewed 4k for $400. The 6k counter-part is almost double in price.

All that said - Are interlocks legal in your jurisdiction? Is your proposed interlock listed for your panel? Are you going to get a permit for the installation of your inlet and interlock?
Yes, it's legal in my area, I already asked the building inspector.
I will pull a permit since it requires a glaring modification to the box.
 
  #10  
Old 01-26-15, 11:50 PM
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From my personal experience, you can run all of those items listed and a few other small appliances/electronics well on a 4,000-6,000W portable generator.
Can I use a standard propane tank (e.g. one used for grilling) to power such a generator? And how long would a single tank last? Are we talking hours or days?
I know off the top of my head that Generac makes 2 models designed to run directly off propane cylinders - the LP3250 and the LP5500. Running a window a/c, fridge, PA system, and a few lights I would get about 15 hours off a 20# tank of propane on the LP3250.

There are also many aftermarket kits available to convert standard gasoline generators to run on propane. I have a Generac 7550EXL converted with one of those kits, that can run on gasoline, natural gas, or propane. Another member here, Furd has a similar setup using a Yamaha inverter generator. We'd be happy to help you do your conversion of you choose to go that route.
 
  #11  
Old 01-27-15, 06:00 AM
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Are you saying I can run any common household appliance directly off a generator? I'm reading otherwise from various google'd articles but I don't know if they are mostly fear-based campaigns.
It really depends on the generator size and quality. Some have pretty good voltage and frequency regulation and some really poor. The larger the generator, generally better regulation. Since you are looking at the bottom end of the price range of small generators, I would be careful about running digital stuff directly on the generator and only do so through a UPS or power conditioner.
 
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