portable generator, txnfr switch?
 

Suppose you got a small portable generator (2000 to 5000 watt), and want to run the key stuff during a 12 hour to 2 day power outage: furnace (mine is gas with electric blower), water heater (ditto), cable modem, wifi. I don’t consider the fridge a key thing, and the freezer stays adequately cold for a couple days. I don’t need to light the house during power outages, with LED flashlights so long-lasting now.

Would the best (easiest, cheap, but safe) way be to run a subpanel with transfer switch, wire that key stuff to the subpanel, and power just that subpanel from the generator?

I’m not talking a whole house generator - this is for an urban house, we get outages of 12 hours to 2-3 days, but only every few years. 12 hours is NBD (flashlights, fireplace, candles, blankies, hot chocolate from the gas range). 2 days gets weariesome, and cold.

We had a sub-panel installed with the necessary circuits breakers to engage certain circuits (water pump, refrigerators, sump pumps, TV, etc.) by an electrician. The plug for the electric cable for generator power (not whole house) is in the garage and the sub-panel right next to the main panel in the basement.

Very easy switch over. It is not automatic.

The generator runs just outside the garage when needed. We did have the cable from the generator to the plug made because I wanted to ensure the generator was outside when running.

It was less than a grand to have everything professionally done but that was over 15 years ago.

I will be watching this!

I too want to get a small Honda inverter generator, and a practical way to hook it up to the house. Same thing, run the natural gas furnace, modem and router, and maybe the fridge for a hour or two if necessary. We have not had a power outage last more than a few hours in 24 years, except during one ice storm 10 years ago and a 12 hour outage then.

We do have a natural gas fireplace, but it is mostly decorative, and the only time it is lit is when the power is out.

My neighbor spent 12 grand on a Generac whole house generator installation and setup about 6 years ago. In 6 years he says it has been needed for 18 minutes total. That is some expensive electricity at 667 bucks per minute.

5000 watts is a lot more juice than I thought, btw.

Instructions on the manual switch over are on the sub-panel as is a load management chart, meaning I can turn off certain functions (well water pump is a huge draw) and add others and still stay comfortably under the generators capability.

I like to stay cool, for instance, so I have a roll around portable 120v A/C unit I'll take off line when required.

The other thing the electrician did was keep a "tell tale" light so we know when power is restored...really handy to know.

Be wary of those that say backfeeding the panel is OK. Technically it is but you really need to be careful doing it that way.

I needed that water heater with a blower today. Hot water line froze. Cold side was fine.:D

I looked up watt draw of stuff like gas furnance blower, hot water heater blower - around 500 w typical. So maybe a Honda 2200 watt generator would be enough, to keep just the key things running. I read that genset runs for 8 hours on 1 gal gasoline. I’d only have to store 5-10 gallons. A power outage longer than 72 hours is very unusual here. The longest I’ve experienced in 16 years of living here was power out for 3 days
and cable internet for a week. (We moved into a hotel.) I’ve never been motivated to get any sort of genset. And to be honest, I still might not. But it’s interesting to think about.

Have a transfer switch installed or maybe DIY that? I have two Honda EU2000's that are probably 12-15 years old now. Super quiet and reliable. We regularly take one in our travel trailer or both if we know we might want to run the AC. The only reason I have two in the first place was to run the AC at the race track with the dogs in the old RV. They can be tandem wired to produce 4000w. I don't have a switch at the house because we have a gas fireplace that can heat the living spaces adequately.

Make sure to have a main breaker lockout added to your main panel so you can't backfeed to the grid.

There is a kit available that wires into your main panel, and has an "inlet" -to activate that you have to slide a switch over that cuts off the main breaker in the panel, preventing you from backfeeding the grid. You then plug the cable into your generator. You can manually control which circuits are fed by turning breakers on or off. You could do the same thing with a subpanel, sure, at added expense.
Like this:


https://m.media-amazon.com/images/W/..._AC_SS450_.jpghttps://www.amazon.com/GenSafety-Generator-Breaker-Panel-Interlock/dp/B09RGP1QR3/ref=asc_df_B09RGP1QR3/?tag=hyprod-20&linkCode=df0&hvadid=563702687488&hvpos=&hvnetw= g&hvrand=4231858892423159635&hvpone=&hvptwo=&hvqmt =&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9008352&hvt argid=pla-1642387760306&psc=1


They're available for most panels. You do need space for the inlet circuit breaker.

Well, I can chime in on this as I have been running a portable generator when we have power outages. I just finished a 3.5 hour stint due to the severe weather here.
When there is a chance of outages, I bring my generator in the garage. This way it is close and ready. When the power quits, I disconnect my dryer hose and run the 2 heavy power cords into the basement. I have 2 outlets closeby of which one is on the A side of the breaker box, the other on the B side. I start the generator...with nothing plugged in, so it can warm up to operating temperature. In the meantime, I switch off the main breaker and turn off what I do not need to power. Then I plug in the cords to the outlets described before and the generator. Hot damn...I got 220 power. Furnace and sump are primary circuits, well pump, refrigerator, and a few lights next. With the 220 I can dry clothes or run the stove. Those I can switch on if needed at the cost of turning off a couple others temporarily. I do all this on a 5k portable generator, and have been for 23 years.

I do long for a transfer switch though. It would make things much easier.

I was going to post the following hours ago, then the wind took out a tree down the street ... and the internet with it.

I recently completed such an install and, after weighing the benefits/shortcomings of the two, chose the less convenient option of an interlock device over a transfer switch.

Without going into the advantages of a transfer switch (and there are definitely some advantages), I went with the interlock device, primarily because it allows me to pick and choose which circuits to have on at a given time, an advantage that for me, outweighed those of the transfer switch.

My house is rural, and without natural gas service, is all electric - heat pump, water heater, range ... all the really energy-intensive stuff. I'd look at whole-house propane (had it in another home and liked it), but all of those items are essentially brand new and the cost of replacing them just means it doesn't make sense.

Anyway, because it's all electric, and because I might need/want the stove and water heater during the day and the heat pump at night, and because we definitely need the well pump, lights and communications at all times, and because I cheaped out and bought only a 13kw generator which can't power everything at once, I wanted to be able to select any of my circuits, not just eight or ten.

Yes, it's less convenient, but the ability to switch off one or two energy intensive circuits and switch that power to something different at any time, and within just a few seconds, made the interlock a better choice for me. If you're going with an even lower output machine it might be a good choice for you, too.



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[QUOTE=greglepore;11879703]There is a kit available that wires into your main panel, and has an "inlet" -to activate that you have to slide a switch over that cuts off the main breaker in the panel, preventing you from backfeeding the grid. You then plug the cable into your generator. You can manually control which circuits are fed by turning breakers on or off. You could do the same thing with a subpanel, sure, at added expense.
Like this:


https://m.media-amazon.com/images/W/..._AC_SS450_.jpghttps://www.amazon.com/GenSafety-Generator-Breaker-Panel-Interlock/dp/B09RGP1QR3/ref=asc_df_B09RGP1QR3/?tag=hyprod-20&linkCode=df0&hvadid=563702687488&hvpos=&hvnetw= g&hvrand=4231858892423159635&hvpone=&hvptwo=&hvqmt =&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9008352&hvt argid=pla-1642387760306&psc=1

I like this idea. Prevents mistakes.

I was gonna recommend this one.

Timely thread (it is 5°F outside - without the wind chill - as I write this) and thanks for the suggestions.

I have a 4.3kW portable I got awhile back (actually as part of a service award from my company) and awhile back bought a natural gas adapter but never did any of the wiring or gas plumbing to outside where the generator would sit, largely because the gas line and the electrical service are on opposite ends of the house.

However this thread, and the extreme drop in temperature (53°F to 5°F in about 12 hours) has me thinking that I should do this sooner rather than later, forgo the natural gas hookup for now, and just keep an adequate supply of gasoline in the garage.

Does your NG adapter also allow use of a propane tank?

Thinking about it, it seems more convenient to store propane than gasoline, if only because propane doesn’t go bad.

Last December when the big snow hit our area we were without power for eleven days. I have two generators and a bunch of extension cords. I got an estimate for a transfer switch set up at 2 grand. I’ll do it some day but for now all the extension cords will suffice.

Yes, and that's a damn good idea. I used to have a gas grill and those tanks had a very long shelf life. They are also readily available quite locally.

I wonder how long one standard (grille-sized) tank would last running my generator? It is rare that we have power outages, but we did lose power for a full week some years back.

I am thinking you would need something more substansial than a 20lb propane can for any outage of more than a couple hours.

Generally speaking a 10k - 12k propane portable generator will only run 3-4 hours on a full 20lb cylinder . Personally I wouldn't go any smaller than a 250 gallon tank . Remember all tanks are filled to 80% capacity to allow for expansion . So a 250 gallon tank when full has 200 gallons in it .

FWIW and I'm sure this is well documented somewhere but the energy density of propane v gasoline in this application may make a difference.

https://motorsnorkel.com/propane-consumption-rate/

Here is some info on generator running time on propane.

Edit: looks like 1000 watts for 1 hour requires 20,000 Btu which is roughly 0.9 lb of propane.

So for my minimalist “just heat and net, ma’am” application, which I figure will require less than 1000 watts average, a 20 lb tank can potentially last most of a whole day. That assumes optimal generator choice - powering a 1000 watt load with a 14 kW genset is, I would guess, going to be far less efficient than with a 2 kW generator.

1 gal gasoline has 114,000 Btu, so a 5 gal can of gasoline can potentially last over a day, again assuming optimal genset choice. With multiple refuelings.

IMHO you need to weigh how often you're going to need the gennie and how long you need to run it. Do you need it for water?Heat?Cooling?Food storage?

Sandy kept us on our own for 15 days. I was able to run my entire house on 4000W the whole time (water, heat, refrig, lights).

Depends on the house . We have a well pump so that's 220 . We have a dual fuel heat pump so again 220 . Our water heater is electric so again 220 . For us to have heat/AC and hot and cold water at a minimum I need a decent size generator for whole house. We have a refrigerator upstairs and a freezer downstairs.

In an emergency situation we don't need washer and dryer with the dryer being 220 electric . I " think " with modern soft start technology I could get away with a 10k generator with a 12k adding some insurance . That size is relatively affordable with decent fuel consumption. Most calculations say 17-20k is needed but I think that is maybe for a large family . It is just me and my wife .

I’ll bet you were a popular guy! 15 days is a long time.

Here in urban PacNW, power outages are caused by windstorms, icestorms, and most often wind&icestorms, bringing down trees and powerlines/cablelines. The longest outage I’ve experienced in 16 years here - and only once - was power out for 4 days (internet out for a week). Most outages are only half a day or so, and those happen every other year or so. For a 3 day outage, I’d be fine with just being able to power heat (blower for gas furnace), internet, and spare me a hundred watts for laptop, phone charger, charging battery packs. Hot water would be nice (blower for gas water heater). Freezer isn’t that important to me (worst case, we and the neighbors all eat like kings for a couple weeks).

I had so many 12 gauge extensions running out of my house it looked like the floor of a a server room.

The "Sandy-Q" in my neighborhood was epic.

Just watched a video on this yesterday: https://youtu.be/VdO32pDi4ko

After years of doing the back feeding thing we put in a transfer switch when we bought a Honda 7,000 120/240 inverter generator. I didn’t want to do the Generac etc permanent install because if we sell the house the generator goes with us.
I wanted an install that was electrically safer and something my wife was comfortable doing.
Recently we lost our power for 5 below-freezing days, it came back on and yesterday with the wild winds, one of our trees took all the power lines down.
The Honda runs our whole house; 220 well pump, 220 heat pump, 220 hybrid water heater etc. I did have to move some breakers around to balance the load so the generator wouldn’t alarm due to momentary overloads.
I went gas even though we have a 330 gal propane tank just because we can always get gas. Plus, being portable, gas power gives us the option to help others.
Our generator is installed in the garage with a proper exhaust pipe thimble as well as an exhaust fan with a powered air inlet damper. A CO monitor/alarm is plugged in.
It’s 14 degrees out now, my wife is watching her favorite show and life is good with over 100 hours in the past two weeks.
Welcome to “The Other” Maine.

^^^ Good info thanks for sharing .

When we had our eleven day outage last year people with 500 gallon propane tanks were burning through it running their generators. The propane companies could not get access to peoples tanks because of all the trees that went down. So , having a propane supplied generator was great until the propane ran out.

The down side of any generator is running out of the fuel source . If trees are down blocking access not much you can do . Being frugal by not running 24 hours a day can really stretch the tank. There is no perfect solution .

My brother had one of these installed last year. Cheap ( relatively) and easy to install.
About 1k and less than 1/2hr .
He got great use out of it after a Dec 15 storm had him without power for almost 40hrs.
I'd get one but my utility co will not allow it in their meter. ( dumb)
So I'm left with the old skytrooper method.

Transfer Switch | Global Power Products



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That's the way mine is wired. We just power the kitchen lights and outlets, water heater, furnaces, and a few lights. We were out of power for a while Thursday night and it worked well.

I thought of something. When we replaced our gas clothes dryer with an electric one (bad decision), I was left with an unused nat gas line in the basement. I could extend that line to a hookup on the outside of the house, on the other side of the wall from the dryer location. Then install a propane/nat gas kit on whatever portable generator I get, and voila no worries about running out of fuel, assuming gas is on.

In your scenario I would add a tee at the dryer junction with a shutoff and then extend the line for a generator . That way if you want to go back to a gas dryer it's easy to do .

I think you will find that the line sized for the dryer isn't sufficient to run a generator.

Ah, thank you.

Link stashed here for reference

Natural Gas Generator Pipe Size Chart

I need to start measuring :-)

I can't find the exact outlet, but use an outdoor version of this through the basement foundation wall.

https://encrypted-tbn2.gstatic.com/s...3816g&usqp=CAc

It connects to a duplex outlet near my furnace that are only energized by this plug when a generator is running. Then an extension cord up the stairs to the fridge and whatever else. Saves keeping windows cracked open to run a cord. Also less extension cord length. It's basically a hardwired extension cord that carries no power unless you plug in a cord from you generator.

Also, your truck tow hooks are useful for securing your generator.

http://forums.pelicanparts.com/uploa...1672109088.jpg