Generator Strategy

[JimD]

In Lexington SC we only had a bad thunderstorm, effectively, from Irma. Officially I don't think the gusts quite hit 60 mph. But that was bad enough we were without power a few hours. Second time since we've owned this house, about 4 years. Neither was more than a few hours.

Since the first time, we've switched to city water - so that works regardless of electrical status - and purchased a small inverter I can run off the deep cell from the boat. That battery is about 100 amp hours so if I use the full inverter capacity I would have about an hour. So it doesn't make sense to get a bigger one, to me at least. My dish box and internet electronics only pulls 100-200W. So if we use a tablet to view things on, the demand is very low. If we use a lcd TV, I think it's about 300W - or about what the refrigerator pulls. So with the inverter, I can provide a little entertainment, at least occasionally run the refrigerator and a TV. But only for a few hours. Switching to another boat battery or car battery could provide more time. I've hooked this up to test it and it works but during Irma, I didn't get home until almost 8pm so I just took care of the dogs, ate a bit of food (had to go back out to get it) and then went to bed. Electricity came back on sometime that night. Food was fine in the frig (I didn't open it until the electricity was back.

Longer term, we'd like to switch the hot water to propane (no natural gas available) and put in a direct vent fireplace insert. But we probably need a bit more electricity when it goes out.

To get a generator to run even the smaller of our two heat pumps is hard to justify for the infrequent brief outages we seem to be vulnerable to. We should be too far from the coast to be without power for weeks. It's also difficult to hook up a generator at low cost. You really need a transfer switch and the wiring for it might be more than I want to do. Probably not, however. I get in the panel now when I need to and we have a cutout for the power in the box.

But the idea that intrigues me is to get a small generator, about 1500W and to set up one circuit of the house for it to power when necessary. Would mean some rewiring of outlets but I could do it. I would put the frig on it and the outlet the entertainment is on (would probably be two outlets). Amazon has a single circuit transfer switch really cheap, like about $100. The small generator I am looking at, a Wen, would be less than $200. So for around $300 and some of my time, I could be set up where I could switch to generator power for a very small load pretty quickly. The small generator would be a lot easier to store than a bigger one too (it weighs about 50 lbs). If it was hot, we'd have to get by with fans. If it was cold, we'd fire up the fireplace insert and keep that room toasty. The blower wouldn't use a lot. We could also have a lamp or two on (with a LED or CFL bulb) in the main room.

Other ideas (or strategies implemented)?

 

[gritz]

We live in a mountain community where power interruptions are fairly routine due to tree damage. This time was pretty bad, but we could get out, so we just added ice to one fridge, and used a cooler for necessities to avoid opening the doors. We relied on the gas grille, plus a jump starter and inverter for light and phone recharging. In the winter we use a wood stove.
A simple small generator approach is upwards of $1000 and a whole house one is well over $10,000. I can't justify either. Guess I'm just a camper at heart...

 

[ehpoole]

You are correct that it takes a rather large generator to start a heat pump or multi-ton AC unit, the major challenge tending to be the very high startup amperage required to get the compressor started -- for example our 4-ton AC is at the very limit of our 15KW (22.5KW surge capacity) generator to actually start, though once running it only requires about 5KW of capacity (so ~22KW to start, 5KW to run). Our generator is setup so that it can essentially power the entire house and we simply manually switch off the circuits we do not wish to power so that we stay within a 6.25KW/50A power budget on each of the 120V legs (there is a wattage gauge next to our home's main panel displaying the load on each leg) and a 200A transfer switch handles the transfer between utility and generator sources.

However, be aware that as pertains to small generators and inverters, a refrigerator can be similarly difficult to handle due to the large, albeit brief, startup surge demanded by their own compressors. You may have an efficient refrigerator that only draws 300W while running, but may demand up to 1500W to get started each time it cycles on. This means that if your refrigerator's startup load is taxing for your small generator (or inverter, though soft-start equipped inverters handle such much better) then you may not have sufficient headroom to run other loads if your refrigerator is to cycle on and off automatically whereas a somewhat larger generator would retain sufficient headroom to handle some additional loads while still preserving enough surge capacity to start the refrigerator on demand.

Also be aware that some smaller generators have absolutely terrible AC waveforms and very poor voltage and frequency regulation, which can be very damaging for some electronics. A lot of small and inexpensive generators (of cheaper design, not the top end inverter type models, for example) lack any sort of automatic regulation of voltage and frequency as such requires added electronics and servos to regulate and these cost money. You may also have issues running highly reactive loads, such as many LED and CFL bulbs on smaller generators as they often have great difficulty regulating in the presence of highly reactive loads unless you also have running a sufficient amount of resistive loads to help smooth out the irregularities presented by the reactive loads -- the greater the reactive wattage load versus the resistive loads the greater the difficulty they may experience. They can usually handle a few such bulbs Ok, the problem usually rears its head if you try to run more than a few or combine such with other reactive loads like motors. A reactive load is any load that looks and behaves as either a predominantly capacitive or inductive load as they can create feedback loops and undesirable oscillations in power and voltage if the generator can not manage them properly and sufficient resistive loads are not present to dampen them. Non-reactive loads are those that are predominantly resistive in nature, such as incandescent bulbs and any sort of electric heat source (excluding heat pumps, which are inductive reactive loads) such as space heaters, hair dryers, etc. and these type loads are handled very well by all generators and inverters. You will have to experiment with your intended loads and selected generator, but you may find that incandescent bulbs may work out better for you, especially if also powering other inductive reactive loads like fan motors and a refrigerator since they will provide some counterbalancing resistive loading.

I would suggest keeping your refrigerator a dedicated circuit as it is one of those circuits you do not ever want someone to accidentally trip in day to day use by inadvertently plugging too large a load into an outlet elsewhere leaving your refrigerator potentially unpowered for an extended period. However, that does not mean you can not tie other 120V circuits into your generator, they would simply be on separate circuit breakers in your critical loads subpanel/transfer switch (so you would need a multi-circuit transfer subpanel). Typically the major goals are the refrigerator and lighting circuits and, if there is adequate capacity to spare, possibly the kitchen and an outlet circuit or two, but that would be a lot to try and cover on just 1500W, or about 13A (not even enough for a typical microwave). The other option is, of course, the traditional extension cord route for powering your critical loads and also works well even if a bit less convenient than a transfer switch and an inlet receptacle to plug your generator into the house.

If you want to power electronic loads then look for a generator that includes automatic voltage and frequency regulation (often listed as "AVR") and that is about twice as large as your maximum expected loads as they will provide the cleaner power expected by electronics and reduce the risk of damaging your electronics with undesirable spikes, sags, and surges.

Here in the upstate of SC we usually get ice storms every few years that can knock out power for days to weeks, much like the hurricanes we encounter in Florida and along the coasts. Even here in upstate SC some homes are only just getting their power restored sometime later today and all we had was a very windy day with light rains thanks to Irma. Having a generator to get through such outages, even if extended outages are relatively rare, is a real blessing even if a bit of a luxury for many, but they can be real lifesavers if one has medical issues. The challenge is usually in ensuring that they remain in a ready state so that they actually work when you do need them. That also means ensuring that their fuel never grows too stale and that fuel stabilizer is used if it is a gasoline powered model. Maintenance is often a bit easier with natural gas and propane models since they do not suffer from the affects and contamination inherent to stale gasoline (which tends to gum things up). Diesel generators are also an option if available and are typically more reliable than gasoline models as well since the fuel deteriorates less and they do not have ignition related issues. But if using a gasoline generator then run it regularly, monthly or bimonthly, and periodically exercise it by actually running your intended household loads several times a year to ensure that the alternator is also producing power (some inexpensive generators must sometimes have their field coil reflashed if not exercised regularly to keep it magnetized).

Probably more than you ever wanted, but I hope that some of the above may be of help. Best wishes!

 

[Wyatt Co.]

6500 Watt gen here. Connect the plug, start the generator, flip a switch and party on. I did all the wiring and whatnot and NC Inspection approved. I think all in all it cost me around $500 but I did have a bunch of stuff on hand already.

 

[Tarhead]

You can buy used Hybrid car batteries and an automatic charge controller system on ebay for not much money. Keep it topped off from your main 110v power and use them to power most of your emergency power needs. Add a few solar panels and you are offgrid w/o the need for fuel and upkeep.

 

[KenOfCary]

If you switch your water heater to LP be aware that most now have electric pilot ignition and also have a fan to vent the exhaust outside through a PVC pipe. They won't start without electricity. So plan to connect those sources to your generator or inverter.

 

[Gotcha6]

If your home is relatively new, you may find that the refrigerator is on a circuit by itself.
As for switching to LP gas water heater, be sure to tell your electric company. Co-ops may not care, but some companies will not give you an all electric rate with this change.
Also, when you start to size a generator setup for extended use (more than 2-3 days) you should also think about washing clothes and dishes...... and people.

 

[junquecol]

NEC requires that appliance circuits not be shared with general purpose circuits. We use portable generators, 2250 watt, 3250 watt,and 5250 watt in progressive order depending upon length of outage. Unfortunately since Duke took over Progress, our typical outage has shifted from less than 4 hours to over 15 hours, so generators are now a fact of life. We run drop cords to what we want to run. Gas furnace only requires a 15 amp circuit, with draw being about 1/3 of that figure. Anything that has a circuit board in it needs to be on a surge protector to protect from voltage surges as things come on and off line. The one thing that we have problems with is a 1/2 HP booster pump on storage tank. It just doesn't like "generator electricity." Refuses to come up to speed, but well pump itself does, so we bypass storage tank and booster pump, and pump straight from well. WH is gas. When I replace heat pumps in the next 30 days, one will have hydronic coil fed from gas WH, so heat won't be a problem. We have two window AC units, same brand and model. One refuses to start on generator power, while the other hums right along. May need to add a "Hard start" kit to that one.

 

[McRabbet]

I have a 5500 Watt generator that is wired to my panel through a 30 amp breaker with an approved interlock kit. During a power outage, I shut off my Heat Pump, Dryer, furnace and Hot Water heater breakers and slide the interlock up to shut off my main 200 Amp breaker and prevent any back feed to the incoming Duke Power lines. These cost about $75 and no transfer switch is needed. I have a waterproof box that my generator 240 VAC power cord plugs into and #10 wire to the breaker at the top right side of my panel. Cheapest and safest method I know of.

​

 

[jgpncll]

I have a similar setup as McRabbet. I have the interlock switch with a 50 amp breaker and a 12,000 watt generator. In the event of an outage I turn off all breakers including the main. Slide the interlock up, turn on the 50 amp generator breaker, start the generator and then choose which circuits I want to power depending on load. Works very well and we are comfortable during an outage.

I also had a plumber install a quick connect fitting to my Natural gas line so I can run my generator off NG instead of having to store gasoline. I have a tri-fuel generator.

 

[nn4jw]

I ran into a strange situation back when hurricane Fran passed through here. I was running our refridgerator and small freezer off our generator by way of a drop cord. We were without utility power for about 5 days as I recall.

Anyway, when the linemen were ready to restore power they showed up at our back door and told me I had to shut the generator down before they would do so. They told me they required it to prevent backfeeding from my generator into the grid and possibly hurting one of them. I told them the generator wasn't hooked to our panel or wiring in any way and even showed them the one drop cord with the refridgerator and freezer plugged directly to the generator and nothing else connected.

They wouldn't back down an inch, so if I wanted power I had to shut the generator off. Once I shut it down they still screwed around for another 30 minutes before finally reconnecting the pole fuse. Not enough time to lose much cold, but worrysome anyway.

So, transfer switch or not don't be surprised if you run into something similar one day.

 

[ehpoole]

I ran into a strange situation back when hurricane Fran passed through here. I was running our refridgerator and small freezer off our generator by way of a drop cord. We were without utility power for about 5 days as I recall.

Anyway, when the linemen were ready to restore power they showed up at our back door and told me I had to shut the generator down before they would do so. They told me they required it to prevent backfeeding from my generator into the grid and possibly hurting one of them. I told them the generator wasn't hooked to our panel or wiring in any way and even showed them the one drop cord with the refridgerator and freezer plugged directly to the generator and nothing else connected.

They wouldn't back down an inch, so if I wanted power I had to shut the generator off. Once I shut it down they still screwed around for another 30 minutes before finally reconnecting the pole fuse. Not enough time to lose much cold, but worrysome anyway.

So, transfer switch or not don't be surprised if you run into something similar one day.

In my experience they are generally much more reassured when they see a proper transfer switch as that is generally suggestive of work done by someone who understands Code and the regulations regarding safe generator use and installation (and, perhaps, because with a properly wired generator there is little need for the like of suicide cords and other risky acts). They will often still request a quick inspection just to verify as much.

However, the crew should have been equipped with the necessary PPE (personal protective equipment) and a suitable high voltage detector or meter and probes that they should have been able to use to verify that there was no power being backfed into your transformer. They should also have had a shorting/grounding cable to clamp across the high voltage terminals to safely dissipate any capacitively coupled voltage (leakage current) from the low voltage secondary side of the transformer to the high voltage primary windings. So either your crew was ill equipped with safety gear, were not especially familiar with the work they were supposed to be doing in a residential environment, or were either poorly trained or unusually paranoid. They also could have temporarily just pulled your meter to establish an absolutely positive disconnect between your house and their electrical grid, then reinstalled it once the power was restored. So why they chose that particular tact is a bit unusual since they had plenty of other suitable options. Leaves one wondering what they would have done had they encountered a grid-tied inverter and solar panel setup! I guess they would have made everyone wait until after sunset and a moonless night?!

 

[Roy G]

I contemplated a generator after Fran, but researching them led to the discovery that they burn a lot of gasoline. Some of the 5Kw generators would run through 5 gallons of gas in 8 hours. I have trouble keeping enough gas on hand for my mowers. I decided I would have to suffer through no electricity whenever that happens.

Roy G

 

[patlaw]

I contemplated a generator after Fran, but researching them led to the discovery that they burn a lot of gasoline. Some of the 5Kw generators would run through 5 gallons of gas in 8 hours. I have trouble keeping enough gas on hand for my mowers. I decided I would have to suffer through no electricity whenever that happens.

People who think they're going to use a generator to go off the grid haven't calculated the cost of the gasoline necessary to enable them to do so comfortably.

 

[junquecol]

I contemplated a generator after Fran, but researching them led to the discovery that they burn a lot of gasoline. Some of the 5Kw generators would run through 5 gallons of gas in 8 hours. I have trouble keeping enough gas on hand for my mowers. I decided I would have to suffer through no electricity whenever that happens.

Roy G

Last year after Mathew, we were without power for six days, despite living in shadow of nuclear plant. When the warning sirens were mechanical, rather than electronic, we were usually back online in a day or less. No siren = no nuclear plant running.

 

[KenOfCary]

I contemplated a generator after Fran, but researching them led to the discovery that they burn a lot of gasoline. Some of the 5Kw generators would run through 5 gallons of gas in 8 hours. I have trouble keeping enough gas on hand for my mowers. I decided I would have to suffer through no electricity whenever that happens.

Roy G

The best source of fuel (in my opinion) for a whole house generator is LP or Natural Gas, but a friend of mine swears by diesel. The ones at the Verizon facility that I used to work at were diesel - had enough fuel underground to run for two weeks and power the entire two building complex.

 

[gator]

I have, in the past, contemplated a generator. In discussing this in general conversation with a friend who is an electrical contractor he suggested that I get a 5KW portable. I have natural gas to the house and his suggestion was to get a quick disconnect coupled to the incoming gas line and an outside transfer switch. When the need arises I could wheel the generator out of storage and connect it to the gas line and run the cable to the transfer switch, turn on the generator and go. This would be a quick and easy way to get power to the house with enough electricity to run the basics and be able to store the generator out of the way until needed. I haven't done it yet but I think it is the way I will go if, and when, I decide to do it.

George

 

[Gofor]

Does anyone have an idea of fuel consumption for a 5kw using LP gas? I have a 250 gal tank and have little usage except during sub 32 degree weather.

My AC/heat unit is a hybrid: On the heat side, it runs as a heat pump off the AC compressor but instead of heat strips when it gets really cold, it switches to an LP gas burner. It currently have it set to kick over at 32 degrees but can set it as high as 40. I can manually command it to go the gas by setting it on the "emergency heat" setting. In this mode, the only electric it consumes is for the blower fan. Due to this, I think a 5kw would get me through an emergency power outage in the cold months (ice storms being the most likely culprit), and during warmer weather, would be using it for a basic lighting and recharging the refrigerator and freezer. (Cooking will be on coleman stove or gas grill). The low incidence of power outages here doesn't warrant a full blown set-up.

To set this up, I will most likely need to have the LP gas company set up an additional feed line for the generator with the appropriate regulator (depending on the flow requirements), as well as an approved electrical isolation switch for the power subpanel which I would use for power management. I do have an unused gas log line with regulator that may be sufficient, but may not have the capacity to feed a generator. However, if the consumption is too high, it probably would not be worth all the effort.

Just brainstorming a bit.

Go

 

[junquecol]

I have, in the past, contemplated a generator. In discussing this in general conversation with a friend who is an electrical contractor he suggested that I get a 5KW portable. I have natural gas to the house and his suggestion was to get a quick disconnect coupled to the incoming gas line and an outside transfer switch. When the need arises I could wheel the generator out of storage and connect it to the gas line and run the cable to the transfer switch, turn on the generator and go. This would be a quick and easy way to get power to the house with enough electricity to run the basics and be able to store the generator out of the way until needed. I haven't done it yet but I think it is the way I will go if, and when, I decide to do it.

George

You left out "Electric Start." 5 KW generators will have a 9 -10 HP engine on them. Then newer OHV engines start a lot easier than the old L head engines. If you can't start it, then there is no need to own it. With electric start, wife is able to start generator if she remembers to turn on fuel.

 

[JimD]

I found a data sheet for my refrigerator and thought the information might be of interest. It was new in 2013 and is 26 cubic feet. Locked rotor amps is 9.3. defrost is 3.75a. so if I start it in defrost, the little generator would barely handle it but that seems unlikely. Normally it would not be in defrost and the frig plus about 4 amps would work. Full load for the compressor is just 1.75a. there are a few more loads but running load isn't a problem.