Generators and generator transfer switches?

[Soli]

Going on 15 years ago we had a second breaker panel with an interlock installed. An outlet from the second panel is hard wired on the outside of the house. When we need the generator a pretty major cord (two male ends NO! lol just went and looked... it was late when I typed this) is plugged into the generator and that outlet. I switch off the breaker for the line power and switch on the breaker for the generator power. This is where the interlock comes in - only one of those breakers can be "on". The interlock physically prevent both from being "on" at the same time.

The second panel is a subset of all the outlets/hardwired equipment in the house - basically the kitchen, garage and family room. We cannot run the whole house off the generator. With a 5,500 watt generator we run:

Fridge
Small Chest Freezer
Gas Furnace
Gas Stove Top
Garage Door Opener
Approx 12 lights (many canned lighting)
Approx 10 outlets

We tend not to turn on the kitchen canned lighting, it's the majority of the lights and really works the generator. We run led lamps from the outlets, plus a couple of regular ceiling lights. Also the router, TV, receiver, BR, and my desktop.

A gallon of gas runs the generator between 2 and 3 hours. We tended to run it from around 6 to noon, shut it down for a couple of hours, then 2 to 8 or 9. But it never got really cold, other times we've run longer hours to keep the heater going.

Kept us comfortable for the week we were out of power.

One thing that's changed is the availability of really powerful, portable, rechargeable led lights. We no longer miss not having most of the house powered, we just use those in the other rooms.

 

[msgriff]

Those interlock kits were a game changer for residential transfer switching. Very affordable. They can be defeated or easily bypassed, so I wonder if they will eventually lose their CTL listing. We used to use Kirk Keys for very large non-automatic installations. Generator size has a lot to do with your expectations and load management. Non-electric or an alternate source of heat is the key.

 

[jbett98]

I've found the smaller generators tend to burn up the crankcase oil when run hard all day.
Most of them now have a low oil sensor that will kill the motor if it gets too low.
Keep some extra oil handy just in case.

 

[ATCclears]

@DaveLikesGuns this is a copy/paste of an old email sent to friends, but generally still relevant to your posting and question. You're looking at some much higher needs given your furnace and cooktop/stove are electric. My furnace, hot-water tank, and cooktop all use natural gas.


So the three big things you'll need:
- generator
- generator-transformer box (aka gentran)
- thick 220v cable from generator to gentran
- certified electrician to install the gentran, and make you a cable

I was into mine for say $1500 back in 1997. You could probably get into same for $2000-$2500 today with an install by a certified electrician.

If you choke on the price, ask yourself what it might cost to replace the food each time in the fridge and freezer. Add to that any costs if you went to a hotel, and then of course the intangible value of simply continuing most of your current way of life without too much interruption.

First, what can you power?
- Yes to a gas furnace. You're just running the blower and the temp sensor. Probably no on an electric furnace.
- Probably no to an electric hot-water tank (if gas, no electricity required)
- Yes to a microwave
- Yes to a 120v fridge
- Yes to a 120v freezer
- Yes to TV, computers, lights
- No to an electric oven or cooktop.
- No to an electric dryer
- Probably yes to a sump pump (if you have one, and if it's 120v)

You'll need to assess what can be powered by the generator. There are limits. You can't have everything running at once since the generator will have a finite output of electricity. For example, the microwave call pull up to 1000 watts for a large, hi-power model. The good news is that everything doesn't run at once, but I do try to keep the total load down on my generator so as not to damage it.

Generator. Many options. You can probably get a good one at Costco for $800. Two key considerations are total continuous watts available, and then do you go with manual/pull start or electric start. Mine is 5000 watts continuous and 6250 surge/temporary watts. I would recommend at least 5000 watts for a typical home. My generator is also a pull start. The pull start on a 10hp engine is fine for me but difficult for my wife. A generator with an engine larger than 10hp may be harder to pull start.

Gentran. This controls what circuits get powered by the generator, and keeps the electricity within your house. Buy a unit/panel with at least 10 switches. 1 switch = 1 circuit breaker in your house. Also, you might get one with a watt meter for each side of switches since this gives you an indication of how many watts you're pulling at that point in time. Each Gentran switch tends to have 3 positions: Line (typical power), Off, and Gen (your generator). So in real use you flip the individual switch from Line to Gen and *tada* that circuit is now getting juice from the generator. It's that easy. It's also safe since your generator is not providing power back out on the line, energizing the transformer, and potentially jolting/killing a lineman upstream from you.

Wiring in the Gentran. Work with the electrician to determine what circuits you want to connect to the Gentran (you might even pre-identify and mark the circuit breakers if you're paying the electrician by the hour). The electrician can take it from there.

Cable. The electrician can make you an appropriate cable with 220v connectors on each end. Ensure that the cable is long enough so that the generator is not running right next to your house. Mine is 50 feet long and I think it cost me $5/ft at the time (it is almost 3/4" thick). I keep my generator in the garage to reduce exposure to the elements when it is idle, but when it's running I've had it out un-sheltered in the wind/rain/snow and never had a problem.

Maintenance on the generator. This is critical. Don't let it sit for a year or two and assume it will magically start. I pull my generator out 3-4x a year and run it for 20min. I also change the oil every Fall regardless. If you have an electric starter then you'll want to keep an eye on the battery on the generator. I've had the same $500 generator since 1997 and it's never failed us. Most outages have been a few hours, but in 2006 there was a bad windstorm and we were on the generator for perhaps 30 hours. I also tend to run the generator for 20min in advance of a large storm.

Spare fuel. Every generator is different. Mine burns approx 5 gallons of gas every 8-10 hours. I try to keep about 20 gallons of fuel in the shed, and use/replenish via the generator, lawn tractor, etc. such that the fuel isn't too old.

Suggestion. Buy the generator at Costco (or other), and then perhaps the Gentran at Home Depot if they're still offering a referral service to certified electricians.

Please let me know if any additional questions.

 

[ron]

edzz is correct. At a minimum you need to install a 30 amp or 50 amp 2 pole breaker in your panel with an interlock to the main breaker. What this does it only allow one or the other to be on at a time. Linemen can get killed by people who illegally back feed. You don't want to be that person.

Panel cover interlock switches are inexpensive compared to a transfer switch. Power up the whole house limited only to KW load rating
of Generator. They are legal and available for most all panel manufactures. Interlock the main with the gen breaker so only one
can be closed at a time.

MUR-100X Murray Generator interlock kit 100 Amp panel Transfer switch | eBay

Murray Generator Interlock clip. Kit Includes: Instruction, labeling, drill bit and interlock clip.

www.ebay.com

An outlet from the second panel is hard wired on the outside of the house. When we need the generator a pretty major cord (two male ends) is plugged into the generator and that outlet.

Two male ends??? WRONG That is what we call a suicide cord. They did it wrong. House Generator receptacle connected to the house
panel is a male. Cord must me a male end at gen and female end at house. Retired Electrician

Conntek DIY Wiring Generator/Industrial NEMA L14-30P 30 Amp 125/250-Volt 4-Prong Locking Power Inlet Box 80601-GYBX - The Home Depot

This is a 30 Amp 125/250-Volt L14-30 Power inlet box that is designed for outdoor use and can be hardwired directly to transfer switches or panels. This rain-tight, rustproof structure is perfect with

www.homedepot.com

 

[308]

Edited..

 

[ron]

 

[308]

Sorry it is early I corrected it. Thanks

There are quite a few suicide cord vids on youtube. I think I'll pass on that option.

 

[m8112]

I bought a used rental return Miller welder/generator set for my backup whole house system. been running it for years. My home is all elect and 10kw 50 amp generator supplies all the power. I do have to manually manage my power consumption. The welders are made to run for continue service long hours. I wired a 220v 50 breaker into main panel to a 50amp receptacle and use a 6 awg braded copper cord. Power goes out, I turn off the main breaker hookup the cable to the generator turn off all 220 breakers start the generator then turn on the 220 breakers as needed.

 

[The Heretic]

You'll need a 220v generator fo3 the stove and water heater.

you're probably looking at at least a 15kw to run all that at the same time.

You need to prioritize what you need during an outage. The dishwasher should not make this list.

And the dryer. Clothes washers run on 110 usually, but will take a bit of juice to get them going as they use a motor.

Most people can do without a stove by using a hot plate and/or microwave and/or toaster oven.

Something to consider is the rpm the generator runs at. A good diesel/duel fuel generator will last alot longer as its running at 1800rpm vs 3600 on cheap units. Pay attention to the rpms.....

^This. Generally only the larger diesels run at 1800 - unless they are an inverter system which adds more cost but IMO is worth it.

As others have said, consider the "surge" or "starting" loads of various appliances/etc.

Anything with a motor in it will require more power to start than to run. A/C, central air, heat pump (huge load), fridge/freezer, washer/dryer, dishwasher, well pump, etc. - any or some of those can take 2-3X (or more) of their running KW load to startup.

 

[Soli]

Two male ends??? WRONG That is what we call a suicide cord. They did it wrong. House Generator receptacle connected to the house
panel is a male. Cord must me a male end at gen and female end at house. Retired Electrician

Well yeah, ignore that. It's not two male ends, just went and looked. Don't know what the bubblegum I was thinking, the cord is male at the generator and female at the wall. The outlet is male. I think I'm just so used to outlets being female that I wrote that.

 

[solv3nt]

I'm an electrical engineer licensed in Hawaii, Kansas and Texas. Give me a shout; I can't do your drawings, but I can tell you what you need.

 

[JohnnyMac]

If you're just looking for a higher capacity generator that you can run a few things off of, I just picked this one up from Costco (on sale in store for $699) and for what you get, it seems to be a pretty good deal. I looked around quite a bit before I pulled the trigger and it seems like anything of any quality over 5000w pushes $1k. It'll get me by until I pony up for a whole house Generac unit.

I have a dedicated 220 outlet in the garage that can only be energized when the main is breaker is open using a device similar to what @ron shows a few posts up. Then I just shut off the breakers that aren't critical and run what I need. Good luck!

Costco Firman Genset

 

[USMC1911]

Just backfeed the dam thing already.

 

[USMC1911]

If you're just looking for a higher capacity generator that you can run a few things off of, I just picked this one up from Costco (on sale in store for $699) and for what you get, it seems to be a pretty good deal. I looked around quite a bit before I pulled the trigger and it seems like anything of any quality over 5000w pushes $1k. It'll get me by until I pony up for a whole house Generac unit.

I have a dedicated 220 outlet in the garage that can only be energized when the main is breaker is open using a device similar to what @ron shows a few posts up. Then I just shut off the breakers that aren't critical and run what I need. Good luck!

Costco Firman Genset

I have two generators I use. One is a 3k Honda for my smaller trailer and one is that Firman you posted. So far that Firman has been solid and fairly stingy on fuel. Probably have 300 hours on it already and other then oil changes its had zero maintenance.

 

[Kruel J]

Suicide cords and backfeeding? Yikes, lots of dangerous advice here.

 

[USMC1911]

Suicide cords and backfeeding? Yikes, lots of dangerous advice here.

Been done for a LONG time. I guess if your a complete moron you could get hurt. Backfeed is and has been used a lot.

 

[jbett98]

Suicide cords and backfeeding? Yikes, lots of dangerous advice here.

It's the American way.

 

[v0lcom13sn0w]

my 3500/4000watt predator generator powers my panel with a transfer switch. it powers everything in my house except my dryer. i have a gas stove top/oven, gas furnace, gas water heater and ALL LED lights so that makes it easy. it powera 2 refeigerators and a deep freeze. my 2600+ sqft house was 72 degrees during the day. id crank it to 80 degrees before bed and wake up to the house being 70. the outage lasted 4 days here. i did not run 24/7. i ran it for about 8-10hrs per day.. i went through about 15 gallons of gas. i changed the oil before the outage, again after 2 days and then finally when the power came back on. i keep extra oil, minumum 20 gallons of fuel and spare spark plugs on shelf.


the whole street was dark until day 3 when people started getting generators.

heres my place when everyone else was dark

yes i may have been flexin on the neighbors a bit with the porch light on... lol i turned them off after the picture...for more reasons than the "hey look at me i was prepared aspect" im not that big of a douche.

 

[solv3nt]

my 3500/4000watt predator generator powers my panel with a transfer switch. it powers everything in my house except my dryer. i have a gas stove top/oven, gas furnace, gas water heater and ALL LED lights so that makes it easy. it powera 2 refeigerators and a deep freeze. my 2600+ sqft house was 72 degrees during the day. id crank it to 80 degrees before bed and wake up to the house being 70. the outage lasted 4 days here. i did not run 24/7. i ran it for about 8-10hrs per day.. i went through about 15 gallons of gas. i changed the oil before the outage, again after 2 days and then finally when the power came back on. i keep extra oil, minumum 20 gallons of fuel and spare spark plugs on shelf.


the whole street was dark until day 3 when people started getting generators.

heres my place when everyone else was dark
View attachment 832750

So that's where they keep the guns!