How to add the generator power input to the switch

[teetee]

Here is a question that I can use some input.

I have a forced-air furnace that relies on 110v power for the fans to do their thing. Recently we had a power outage (nor'easter in New England area). This is the first year I start using a small portable gas inverter generator (WEN 56225i 2250W peak 1800W sustained) to keep the fridge and network equipment on during the outage.

I realized that if the power outage occurs when it's below 0F outside, things can get dicey (frozen pipes and frozen toes) so adding a receptacle to the furnace for the generator input seems to be a reasonable thing to do.

Here is the photo of the existing conduit goes to the furnace. The switch is not working half of the time so I am thinking to replace it as well. I am not looking for a transfer switch at the circuit breaker.

 

[frank]

I am sure there a lot of youtube videos on this. If I were you I would hook up a circuit breaker with whatever amps you can carry to a heavy enough extension cord that will plug into the generator 230volt end. if you have a power outage, turn off the main breaker in the circuit panel and turn on the one that feeds from the generator. just make sure you disconnect the generator before turning on the main in the circuit panel.

 

[jimbee]

You can buy a furnace transfer switch. Here is an example sold at Home Depot. https://www.homedepot.com/p/Reliance-Controls-Furnace-Transfer-Switch-TF151/202216476

 

[CRLLS]

I know of no "inherently safe" method to implement what you want without a proper lockout or transfer switch. Unlike your refrigerator and WiFi/internet equip, a furnace is hard wired. There is no plug to disconnect from the house wiring and plug into a generator. Many people do Rube Goldberg setups like you are asking about without a proper setup. It can be done. It is not foolproof or safe, especially for others to convert from one to another. Have I done it? Yes. Would I do it again? No!

BTW. Every person with a home portable generator only uses it during a power outage. It is not a reason to skip the safe way.

Definitely I would say replace the malfunctioning switch regardless of your decision. An intermittent switch can be a fire hazard, in and of itself.

edit: I was not aware of the unit that jimbee posted. It looks like it might work for you.

 

[njhowie]

That generator is small - will it have enough power for the furnace, fridge, network equipment and anything else you want/need?

 

[Dash man]

Here is a question that I can use some input.

I have a forced-air furnace that relies on 110v power for the fans to do their thing. Recently we had a power outage (nor'easter in New England area). This is the first year I start using a small portable gas inverter generator (WEN 56225i 2250W peak 1800W sustained) to keep the fridge and network equipment on during the outage.

I realized that if the power outage occurs when it's below 0F outside, things can get dicey (frozen pipes and frozen toes) so adding a receptacle to the furnace for the generator input seems to be a reasonable thing to do.

Here is the photo of the existing conduit goes to the furnace. The switch is not working half of the time so I am thinking to replace it as well. I am not looking for a transfer switch at the circuit breaker since I only use the generator when the power goes out.

If I were you I’d get a couple of portable heaters that your generator can support, rather than set up a safety hazard without a transfer switch.
There is also heat tape you can wrap around any pipes at risk of freezing.

 

[corn18]

Please stop using that switch immediately and do not hook up your generator. That setup will back feed electricity into the grid and electrocute the poor folks that are trying to fix the power outage. And when the power does come back on, you will have line power feeding back into the generator and two sources feeding the furnace. Something bad will happen.

Replace that switch with an automatic transfer switch like this one:

https://www.amazon.com/Technology-Research-41300-Transfer-Switch/dp/B00IYUPRUG/ref=sr_1_4?crid=3SH7O3YCCZ2CG&dchild=1&keywords=30+amp+automatic+transfer+switch&qid=1635513877&sprefix=30+amp+auto%2Caps%2C120&sr=8-4

$80 and everyone will be safe. Easy to hook up.

 

[marko]

Careful with the fridge!! They now have very sensitive microprocessors that freak out with even mild voltage swings. Costs a lot more to replace/repair than any food lost!

 

[OldShooter]

@teetee, I have wired a couple of houses, installed and hooked up a couple of manual transfer panels, and am an MSEE. From that perspective:

1) You will need to hire an electrician to do whatever you end up wanting. From the way you have phrased your question I conclude that you do not have the necessary expertise for a DIY.

2) If I were doing this I would install a proper manual transfer panel. These panels take mains power and generator power and allow you to switch between the two while mechanically preventing both from being connected at the same time. Via this route, you can easily switch important circuits like the furnace, some lights (a lot of lights, actually, if they are LED), fridge, internet boxes and computers, etc. You will eventually want to do this, so better to just bite the bullet and do it now.

3)Absent a transfer panel, another route would be to rewire the furnace connection to be made via a cable and a plug to an outlet. Then to switch, you just unplug from the mains power outlet and plug into an outlet strip being fed by the genset. I am too lazy to dig in the code, which may frown on this, but it is safe and easy. But you still have the problems of running cords all over the house to feed the fridge, lights, etc. And these cords have to be heavier ones, #14, #12, and maybe even heavier depending on the lengths and the loads.

4) I have never used of the Amazon products like the linked one, but if you are going that route be absolutely certain that the product complies with relevant UL specifications and is certified by UL or ETL. This route, again, is very limiting and doesn't help with all your other power needs.

5) I am skeptical about @Marko's microprocessor concern. A good power supply designer should have dealt with potential power quality issues if for no other reason than to forestall warranty claims against the OEM. I would like to see links or references to reports, studies, or statistics before being worried about this. There will be anecdotes, of course, but a few anecdotes don't prove anything.

 

[38Chevy454]

The transfer switch is safe, it is set up so that your furnace uses house power *OR* generator power. It isolates the house power so there is no backfeed. See how the switch is GEN-OFF-LINE? Line is house power input, which is disconnected when the switch is put into GEN power input. You can't have both inputs live at the same time connected to each other.


Technically you could take the furnace lead and put a male plug on it. Then put a receptacle in place of that switch in the box. When you lose house power and want to switch to generator power just unplug the furnace from the box and plug that into the generator power cord. Or if doing service on the furnace you can unplug the furnace so it is unpowered. But I am sure this is not to code requirements. It is effectively what the transfer switch does, just the transfer switch is cleaner and nicer.


edit: Oldshooter and I posted basically this same thing at same time

 

[skyking1]

3)Absent a transfer panel, another route would be to rewire the furnace connection to be made via a cable and a plug to an outlet. Then to switch, you just unplug from the mains power outlet and plug into an outlet strip being fed by the genset. I am too lazy to dig in the code, which may frown on this, but it is safe and easy. But you still have the problems of running cords all over the house to feed the fridge, lights, etc. And these cords have to be heavier ones, #14, #12, and maybe even heavier depending on the lengths and the loads.

That is how I have the group B well wired. Both the submersible and the pressure pump plug into a NEMA twist lock outlet. Our 240v generator will run one or the other. I have a cord with the same plug. It works and is perfectly safe, with no possibility of backfeeding.

 

[1242Vintage]

Another vote for a properly wired transfer box or switch. We have a Reliant brand manual transfer box installed by a qualified electrician. Like yours, my generator is portable so no need for an automatic switch since I need to roll the generator out of the garage, plug it in and start it manually anyway. Labor and material was right around $1,100.

My 5kw generator powers nearly everything in our 2,600 sqft home … except AC and big shop overhead door opener. I’m curious if a smaller generator will be able to run your furnace blower, in addition to other demands.

 

[Jerry1]

Agree that a transfer switch is the proper way to go, but I don’t agree that hooking into that switch will back feed into the grid. I’ve hooked into that switch before and if you hook into the right wires and, most importantly, disconnect any other wires, you’ve isolated the furnace and it’s safe. If you have no idea what you’re doing, then you should not be doing it, but it’s not hard and it’s not automatically unsafe. Though, as is being said, a transfer switch is the best and proper way to go.

ETA
Personally, I like this manual one.

https://www.homedepot.com/p/Reliance-Controls-Furnace-Transfer-Switch-TF151/202216476

 

[marko]

5) I am skeptical about @Marko's microprocessor concern. A good power supply designer should have dealt with potential power quality issues if for no other reason than to forestall warranty claims against the OEM. I would like to see links or references to reports, studies, or statistics before being worried about this. There will be anecdotes, of course, but a few anecdotes don't prove anything.

Only going by personal experience. We had power go out and when it came back on the fridge died. Repair guy hit us for $400...fried processor. Got a surge protector but it happened again anyway. With all the new electronics, I just wouldn't play around with switching around power sources. YMMV

 

[djsander]

Hire a licensed electrician to do it properly. The downside of do it yourself electrical work when not knowing what to do or all the code requirements is things happen. When unlicensed work not to code causes fires injuries etc. then insurance companies don’t pay. As an earlier poster said you can cause serious injury or death to people working on the power lines. I know everybody tries to diy to save money, but electrical work is not the place to do it.

 

[corn18]

Agree that a transfer switch is the proper way to go, but I don’t agree that hooking into that switch will back feed into the grid. I’ve hooked into that switch before and if you hook into the right wires and, most importantly, disconnect any other wires, you’ve isolated the furnace and it’s safe. If you have no idea what you’re doing, then you should not be doing it, but it’s not hard and it’s not automatically unsafe. Though, as is being said, a transfer switch is the best and proper way to go.

ETA
Personally, I like this manual one.

https://www.homedepot.com/p/Reliance-Controls-Furnace-Transfer-Switch-TF151/202216476

The problem with the OP's setup is I only see one wire going in and one going out. That would indicate that when the switch is in the on position, it is connected to the furnace and the furnace is still connected to the mains. Might as well make up a male to male cord and plug your generator into the dryer plug. That works great and powers everything in the house. No transfer switch required.

I agree that it could work safely if there was more going on than what is shown in that photo. I assumed the worst based on the high tech install I saw in the photo.

 

[finnski1]

The problem with the OP's setup is I only see one wire going in and one going out. That would indicate that when the switch is in the on position, it is connected to the furnace and the furnace is still connected to the mains. Might as well make up a male to male cord and plug your generator into the dryer plug. That works great and powers everything in the house. No transfer switch required.

I agree that it could work safely if there was more going on than what is shown in that photo. I assumed the worst based on the high tech install I saw in the photo.

Yes you can do that and that is what I do. However I would not recommend it. Basically you have a live male end on one end. Some people refer to these as "suicide cords". You have to follow a very strict energizing and de energizing procedure to do this safely. Much safer for the OP to get a proper transfer switch installed by a licensed electrician.

 

[corn18]

Yes you can do that and that is what I do. However I would not recommend it. Basically you have a live male end on one end. Some people refer to these as "suicide cords". You have to follow a very strict energizing and de energizing procedure to do this safely. Much safer for the OP to get a proper transfer switch installed by a licensed electrician.

Please tell me part of your energize checklist is to turn off the mains to the house.

BTW, I was just joking about the dryer hook up. You can kill other people using this hookup method.

 

[sengsational]

Only going by personal experience. We had power go out and when it came back on the fridge died. Repair guy hit us for $400...fried processor. Got a surge protector but it happened again anyway. With all the new electronics, I just wouldn't play around with switching around power sources. YMMV

The problem, which I lightly researched when I was working on a problem like the OP, was that if you have a sine-wave generator, you're less likely to have an issue. If you have a modified sine wave, you're much more likely to have an issue. The moral of the story, don't get that modified sine wave generator.

The OP's generator is safe for fridges:

With power output designed to mirror a pure sine wave, this generator limits total harmonic distortion to under 0.3 percent at no load and under 1.2 percent at full load, making it safe to run laptops, cellphones, monitors, tablets and other sensitive electronics.

 

[OldShooter]

Anyone making or using a male-male cord is automatically on the candidate list for a Darwin Award.

 

[youbet]

If I were you I’d get a couple of portable heaters that your generator can support, rather than set up a safety hazard without a transfer switch.
There is also heat tape you can wrap around any pipes at risk of freezing.

I don't think that would work out. When you're talking about heating (at least to the point of minimal comfort, say 50f) even a small house, you're talking about needing several thousand watts of heater capacity. Way too much for a small portable generator such as OP has.

Note: I'm in Chicago so I'm assuming you're battling sub-zero temps during this ordeal.

 

[skyking1]

yes that is crazy talk. My well system above is NOT THAT!

 

[skyking1]

I don't think that would work out. When you're talking about heating (at least to the point of minimal comfort, say 50f) even a small house, you're talking about needing several thousand watts of heater capacity. Way too much for a small portable generator such as OP has.

Note: I'm in Chicago so I'm assuming you're battling sub-zero temps during this ordeal.

Yes the OP is on the right track with providing blower motor power to a furnace.

 

[freedomatlast]

The simplest, cheapest and one of the safest ways to power the furnace is to do this. BTW, I've done this for 30+ years with no issues. Trace the wire from the furnace and locate a point above where it is no longer encased in conduit. Buy a handy box, 1 cable clamp, a receptacle and outlet cover, and a plug capable of accepting the 14/2 Romex powering the furnace.

Turn off the breaker going to the furnace. Cut the wire and strip the insulation on both ends. On the wire from the furnace, attach the plug. Next, mount the handy box to a secure location such as the joist. Loop the remaining end of the cut wire through the cable clamp and the hole in the handy box. Attach the receptacle and screw the receptacle into the handy box, then attach the outlet cover. Plug the newly installed plug from the furnace into the receptacle. Turn the breaker back on.

Next buy a 12 gauge extension cord long enough to reach from the furnace to outside where you will place the generator. If the power goes out, simply unplug the plug from the receptacle and into the extension cord to the generator. No need for transfer switches and no worries about a surge when the electricity comes back on knocking out a control board in the furnace.

And replace the existing faulty switch immediately!

 

[finnski1]

Please tell me part of your energize checklist is to turn off the mains to the house.

BTW, I was just joking about the dryer hook up. You can kill other people using this hookup method.

Of course turning off the mains to the house is "part of" my checklist. In fact it is first and foremost thing that I do.
I then plug the dual male end (suicide cord) into the dryer outlet, then into the generator.
Only then do I start the generator make sure it is running smoothly and then turn the switch on the generator which energizes the 230 volt outlet to the dryer.
To power down I reverse all steps. turn off switch on gen, shut off generator, unplug cord from gen, unplug cord from dryer outlet. turn on mains.

I have a 5500 watt generator and I comfortably run my entire household for 10-12 hours per 5 gallons of gas.

In NH I get a lot of practice with this setup. Have lost power as long as 13 days in the ice storm of 2008 and many 1-2 day events since. Never had an issue

As I said I would not recommend it for someone who is unsure of anything but I am careful and never have a problem. I never turn mains on with generator either running or plugged in to dryer outlet . Nor do I ever run the gen with either end of the male ended cord loose and unattached at either end. I follow the same exact procedure I described above every time.


P.S looks like I've already been flamed before my response to you. Doesn't surprise me. You can call me Charles from now on.