Looking for an electrician for a question

[tinstar 1114]

I know this is not exactly RV-related but I'm looking for information on a portable RV genset used to backfeed my house.

I have been researching back-up generators for my home. I am wanting an inverter generator (quiet), dual fuel (versatility), 240-volt (hopefully for more power), economical (fuel use and initial genset cost). I know, that's a lot to ask for a reasonably priced genset of $1K give or take.

From my research, I am finding different opinions on the web to my question. I know a 240-volt genset can be wired to both sides of the breaker panel (via interlock) without a problem and that will allow either 120 or 240-volt circuits to be live.

What I am trying to figure out is: Can a 120-volt genset be safely wire to my panel AND feed both L1 and L2. I am aware that only 120-volts would be available. I was reading on an electrical forum (and I don't know if it's a professional answering the question or just a do-it-yourselfer). Most say it is safe to do so and just wire the hot wire from a 30-amp supply/generator to both sides of the panel. A few folks question if it can't be done safely. I know 240-volt appliances would not work but wall circuits and lights are my main concern. This electrical forum also says the 240-volt breakers would not even need to be turned off since the 120-volt feed are both in the same phase and it would show 0 volts. If this can be done, I could easily keep all 240 breakers off but I would like to know if that is necessary. Obviously, a 240-volt genset would be better so I could feed a 240 appliance if needed BUT availability and cost are a major factor of not being able to do so.

I can and will contact a local electrician as necessary. This is just a question for my initial research

OH, btw I'm looking at the Westinghouse iGen4500 dual-fuel inverter generator.

Thanks, for any help.

[wamcneil]

Originally Posted by tinstar 1114

This electrical forum also says the 240-volt breakers would not even need to be turned off since the 120-volt feed are both in the same phase and it would show 0 volts. If this can be done, I could easily keep all 240 breakers off but I would like to know if that is necessary. .

I'm not an electrician. But I did sleep in a Holiday Inn Express last time I traveled for business (almost a full YEAR ago...yikes, what a crazy covid year...).
I'm pretty sure NO electrician (RV or otherwise) would EVER tell you "Heck yeah, no problem, go ahead and hack your electrical system. I guarantee it'll be OK"...
What you're talking about would probably expose you to massive potential liability, be a violation of local utility rules, municipal laws and a bunch of national electric codes, and could go wrong in a variety of ways, but speaking hypothetically...
When you plug your 50a motorhome cable into a 30a RV plug via an adapter, there's an internal bridge in the adapter that sends the same 120v leg of power to both legs of your 50a 240v RV electrical system.
There's nothing in the RV that uses 240v, so this is perfectly OK.
The same thing would apply if you were to feed one leg of 120v power back into your house electrical system, bridging it to both legs of the house's 240v system.
But in the house, as you noted, you have certain loads that require 240v power, and obviously these loads will need to be disconnected in order to do what you're wanting to do.
So, if you have a positive interlock on this backfeed so the generator power CANNOT be connected at the same time as the utility company's power is connected to your house (and possibly electrocute a lineman), and make absolutely certain to turn off all the double-pole breakers in your house panel, then it should work just fine.
Is it necessary to turn off the double-pole breakers? I don't know for sure, but personally, I would try real hard to never ever intentionally mis-wire any electrical device. I doubt your insurance company will accept "Well, sure, I intentionally hacked my residential electrical system, but, come on, I was pretty sure it wouldn't wind up starting a fire".
Cheers,
Walter

[Ivylog]

I take it you do not store your Windsor at home which has a Onan 7.5 inverter generator.
Never thought about not turning the 240 items off even though they would be the same phase BUT in an electric dryer/furnace the motor is not 240V, just the heating element. Turn them all off when you turn the main breaker off before back feeding the panel.

[tinstar 1114]

Originally Posted by Ivylog

I take it you do not store your Windsor at home which has a Onan 7.5 inverter generator.
Never thought about not turning the 240 items off even though they would be the same phase BUT in an electric dryer/furnace the motor is not 240V, just the heating element. Turn them all off when you turn the main breaker before back feeding the panel.

I do store it at home and I've thought about that exact thing. I don't know where I am supposed to tap into the generator to feed the house panel or what equipment I would need. I assume I would just need 8 gauge wire from the m/h to the panel and then the related items for the panel (interlock switch and a double pole 50 amp breaker).

[twinboat]

There are RVs that have 240 volt dryers, Mr D has one.

No need to switch off the breaker, it just won't work. Its like sticking both wires of a toaster in one slot of an outlet, no current flow.


To use your RV generator, you could install a 50 amp outlet in the generator line before the auto transfer switch.
Then use a power cord to a proper transfer switch on the house panel.

[Biljol]

I am planing on setting up what you could do. Power your house from the genny. To do so I would pull the genny line from before the transfer switch and put in a 50amp duel pole switch or what ever it’s called so in one position it powers a 50 amp outlet in the rv basement or powers the coach transfer switch, then have a 50 amp cord from the home service panel that could plug into the outlet in the rv.

This is of course with the correct breaker interlocks on the house service panel.

Living in AZ the 240/50 amp would run my heat pump, fridge and freezer and in the heat of summer that’s the important items for me.

[Persistent]

You need an licensed electrician to do this. You must meet codes. Some of the best electricians will know. Many will not.

You do not just connect generator wires to your house wires. You must have a transfer switch. To put in the transfer switch you need to disconnect at the house meter, do a code compliant installation, and get it inspected. There are other complected ways. Most are will not meet code.

I am not a licensed electrician. Do not trust what I wrote.

It is possible you could do this your self, but you must first learn the code. Good luck with that.

A 100 amp home 240 volt service entrance is 24 kilowatts. Preventing gross overload of a 7K generator is going to make everything more complected.

It is possible you could kill a line worker or a neighbor. Some places that may be charged as manslaughter. Actually I am not a lawyer. Do not believe what I wrote.

If you don't understand how to connect your RV generator to your house, you don't know how to connect a portable, or fixed installation either.

I wish you good luck and happy trails ahead!

[tinstar 1114]

Originally Posted by Persistent

You need an licensed electrician to do this. You must meet codes. Some of the best electricians will know. Many will not.

You do not just connect generator wires to your house wires. You must have a transfer switch. To put in the transfer switch you need to disconnect at the house meter, do a code compliant installation, and get it inspected. There are other complected ways. Most are will not meet code.

I am not a licensed electrician. Do not trust what I wrote.

It is possible you could do this your self, but you must first learn the code. Good luck with that.

A 100 amp home 240 volt service entrance is 24 kilowatts. Preventing gross overload of a 7K generator is going to make everything more complected.

It is possible you could kill a line worker or a neighbor. Some places that may be charged as manslaughter. Actually I am not a lawyer. Do not believe what I wrote.

If you don't understand how to connect your RV generator to your house, you don't know how to connect a portable, or fixed installation either.

I wish you good luck and happy trails ahead!

I appreciate the advice but interlock switches are sold everywhere and comply with code in all 50 states from what I have found. I know they are legal in Texas anyway. A transfer switch is just a lazy man's way to avoid the inconvenience of manually flipping a switch. I don't mind the 10 extra seconds of throwing the interlock switch. There are 100's of thousands of homes that are wired to accept generator power. I am already certified to do electrical work in my own home so I don't know why I would need an electrician. As far as learning the code that's why I said I will contact an electrician and am seeking input before I do that. I will only do this if it's legal and safe.

[twinboat]

Originally Posted by Biljol

I am planing on setting up what you could do. Power your house from the genny. To do so I would pull the genny line from before the transfer switch and put in a 50amp duel pole switch or what ever it’s called so in one position it powers a 50 amp outlet in the rv basement or powers the coach transfer switch, then have a 50 amp cord from the home service panel that could plug into the outlet in the rv.

This is of course with the correct breaker interlocks on the house service panel.

Living in AZ the 240/50 amp would run my heat pump, fridge and freezer and in the heat of summer that’s the important items for me.

The power cords and switching gear will be 50 amp, but to draw 50 amp, 240 volts, from your generator it needs to have a 12,000 watt output rating.

[Biljol]

True I have a 10kw so genny my heat pump is a 3 ton at 24 amps max load and the refrigerator and freezer are insignificant.

[Biljol]

The 10k shows more than 30 amps may need to investigate. Don’t want to take over the thread.

[twinboat]

Originally Posted by Biljol

Attachment 318749
The 10k shows more than 30 amps may need to investigate. Don’t want to take over the thread.

10,000 generator outputs 41 amps at 240 volts. Plenty of power for an RV but not for a 200 amp house.

[Ivylog]

A Onan 7.5 is only 120V as it’s a DC generator feeding an inverter to get a single 120V output. On the R front corner there is an electrical connection where I’ve added a 30A RV outlet. On my 10K I added a 50A outlet as it’s a true 240V generator.

I probably should stop here but what the heck. If you can’t remember to turn the main breaker off before back feeding power into the panel, please stop reading here:

I store my DP inside my home connected to a 50A outlet and as posted above, have a 50A outlet on the generator and I carry a 50 A extension cord. I also have an exhaust port to the outside and a flex pipe for the generator so I can safely run it if necessary while stored inside.

They call the following a suicide adapter (why I should have stopped) and there will be multiple posts of how stupid and Non “Code” making and using one is. It’s two male 50A plugs connected together and hopefully if you kill yourself by touching the bare lugs with power to them, you haven’t reproduce. If you cannot figure out the rest of the hookup, GOOD.

[Pigman1]

Originally Posted by Ivylog

A Onan 7.5 is only 120V as it’s a DC generator feeding an inverter to get a single 120V output. On the R front corner there is an electrical connection where I’ve added a 30A RV outlet. On my 10K I added a 50A outlet as it’s a true 240V generator.

I probably should stop here but what the heck. If you can’t remember to turn the main breaker off before back feeding power into the panel, please stop reading here:

I store my DP inside my home connected to a 50A outlet and as posted above, have a 50A outlet on the generator and I carry a 50 A extension cord. I also have an exhaust port to the outside and a flex pipe for the generator so I can safely run it if necessary while stored inside.

They call the following a suicide adapter (why I should have stopped) and there will be multiple posts of how stupid and Non “Code” making and using one is. It’s two male 50A plugs connected together and hopefully if you kill yourself by touching the bare lugs with power to them, you haven’t reproduce. If you cannot figure out the rest of the hookup, GOOD.

Yeah, exactly. We farmed before retiring. Knowing what we know, I'd say that less than half of the farms out there that have generators have systems that meet codes. We set poles, wire major out buildings, and run our homes and all farm electrical equipment from farm generators. It's a generator, essentially like your RV generator. Considering the OP's post and his concerns, I'd say he could turn off electric service inbound, open ALL double ganged c/b's and enjoy with a jumper. As Ivylog said, it takes a bit of time and care to make the switch-over, but for someone with a few functioning brain cells, it's not a big deal, and not something you'll be doing every day. The codes, rules, and inspections are all set up for the idiot who doesn't have a clue and doesn't want to learn, and who will do the stupidest thing under the worse conditions.