Looking for an electrician for a question

[twinboat]

Originally Posted by Papachuckl97

I am a licensed electrician and I have another concern other than proper transfer switch and gen load protection that has already been mentioned. Alot of homes I have seen will use a 3 wire romex to feed two 120 volt circuits. This arrangement using a single neutral for both 120 volt circuits depends on the two hot legs being seperate phases in order to keep max neutral load at wire rating (#12 20amp for example). Typically breakers for this type of wiring arrangement do have levers tied together (according to code they should). Without going into the weeds too deep I just want to caution you that there is more to be concerned about than if you should shut off 240v breakers or not. In that regard I would definitely shutoff 240 volt breakers in order to prevent safety hazard and potential device malfunctions. My 2 cents

How would a 240 volt circuit with both hots on the same phase do any damage.

What you discribe is exactly what a 30 amp to 50 amp dog bone adaptor does. Connects both hots together and sends them thru a linked double breaker in the RV.

[SeaBreazer]

Originally Posted by 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.

If you bridged the dual bus bar in your house panel you will have two problems.
1 You take a big risk at burning up you 240 appliances
2 you take a major chance of damaging your house panel

If you want to hook a generator to your house panel first you will need to install a breaker interlock in your panel so you can't have two power sources on at the same time. This is for safety so you can't backfeed the non active source. I have seen years ago a lineman electrocuted in NC because he assumed there was no power in the line when in fact it was live due to a genset was backfeeding the system from a improperly installed backup genset.

My 2cents do it right for everyone's safety.

[beach house]

Originally Posted by KD4UPL

Tell that to the dead lineman's family.
I get so tired of all the arrogant cowboys on these forums who are so smart that they will never ever make a mistake. Not only that their wives, children, and the future owner of their house will never make a mistake either. They claim it's because they're farmers, rural residents, or whatever. For the price of a $70 interlock they'll happily do it the wrong way and practically brag about it.
I grew up on a farm, my father is a farmer, my grandfather is a farmer. Every farm I've lived on has had a generator and they all had a proper double throw switch.

I'm a master electrician in two states if it matters. I can't tell you how many times I've come across people using the "suicide" cord and the "turn the main off" approach. When I explain the dangers the typical response is: "I never thought about that. Really, that could happen? This is the way my friend, brother, etc. told me to do it. Do you think it's dangerous?"


OP, feeding your house from a generator is fine. Install a double throw or an interlock (I recommend the interlock). Get a MALE INLET for your house, they sell them at the same places that sell the interlocks or you can buy one form Lowes or Home Depot. That way you don't need the double male suicide cord. If you want to run a 240v device like a well pump you can use an auto-transformer to make 240v from the 120v generator output. Outback makes the PSX-240; I'm sure there are others.
I think you're best bet is to consult with a local electrician.

Long ago, I had an electrician who I was acquainted with, before he became an electrician. He told me on more than one occasion, that "people all too often mistaken the difference between luck and safety". As the years go by, I realize even more that this phrase applies not only to electricity, but to most things in life that involve unsafe circumstances.



Another wise person told me, you may get away with taking shortcuts, but what about the next person, or when you own mind starts slipping...

[kendall69]

https://blog.norwall.com/generator-t...tor-dangerous/

[Roger6730]

About 4 years ago, I had a stationary generator installed at home. The transfer is automatic and starts the generator. It don’t care if I’m home or not. It is the ONLY truly safe way to transfer power. Just like your mh.
Get a transfer box. Don’t rely on a sticky note or your own memory. It will get someone killed.
That’s my 2 cents.

[rkbeasley]

This may help you. I have a 3500Watt Champion inverter. I pull the main breaker before I ever hook up. Then remove the cover of the breaker box. I have a 20' 10guage extension cord with the female connection removed and replaced with a 30 amp breaker. I snap that beaker into my breaker box. Plug the male end into the generator. Not I have 30 amp service to one side of my breaker box. I can't run any 220 volt appliances. The only thing I can't run is my ac. I have rewired my breaker box to have the connections I wish to use on the side that my generator is connected. My generator sits just outside the garage door with a cable and lock that runs under the door and secured to something inside the garage.

[Concord]

Originally Posted by Papachuckl97

I am a licensed electrician and I have another concern other than proper transfer switch and gen load protection that has already been mentioned. Alot of homes I have seen will use a 3 wire romex to feed two 120 volt circuits. This arrangement using a single neutral for both 120 volt circuits depends on the two hot legs being seperate phases in order to keep max neutral load at wire rating (#12 20amp for example). Typically breakers for this type of wiring arrangement do have levers tied together (according to code they should). Without going into the weeds too deep I just want to caution you that there is more to be concerned about than if you should shut off 240v breakers or not. In that regard I would definitely shutoff 240 volt breakers in order to prevent safety hazard and potential device malfunctions. My 2 cents

I was going to mention this.. You have to understand how the two phases work.. They cancel each other out if properly balanced... If you put the same phase on both sides, you are overloading the neutral (which isn't fused). This used to be allowable code. I encountered this in my daughter's house a few years ago.

[TXduo]

Originally Posted by Concord

I was going to mention this.. You have to understand how the two phases work.. They cancel each other out if properly balanced... If you put the same phase on both sides, you are overloading the neutral (which isn't fused). This used to be allowable code. I encountered this in my daughter's house a few years ago.

It's still single phase 240V being split into two 120V split phase legs, and not 2 phases of a 3 phase power source. It is true that the neutral carries the difference of the two split phase legs, and if the same split phase is on both legs the neutral carries the SUM of the legs. JMHO

[Charlesland]

Short answer is yes if done correctly. You want to be absolutely sure that commercial power is locked out while operating on a genset.

[skyking421]

There are some very dangerous comments that have been made.
I'm an engineer and have NEVER heard of 240v being 2 single phase lines. That's impossible.
240 volts are created by having two 120v lines in OPPOSITE PHASE! When one is positive, the other is negative. That way you achieve 240volts.


CAPS NECESSARY.
IF YOU EVER CONNECT THE LIVE 240VOLT LINES TOGETHER, YOU WILL GET A BIG BOOM! This should be obvious, but that is what some are talking about doing with their generators.
This could be done, if all the outside power is disconnected, but it can be deadly if it were to re-connect to outside power. The deadly part could be outside workers or fires in the home.


If 240volt lines WERE the same phase, you could connect a 100v bulb and it would not light. In reality, if you connect that bulb to 240v, it will immediately go pop. What do you think would happen, if you connect heavy gauge wires the same way? Boom!



To sum up, NEVER connect LIVE 240volt lines together!


Hope I don't get flamed over this. Just trying to prevent serious harm.

[KanzKran]

Originally Posted by Concord

I was going to mention this.. You have to understand how the two phases work.. They cancel each other out if properly balanced... If you put the same phase on both sides, you are overloading the neutral (which isn't fused). This used to be allowable code. I encountered this in my daughter's house a few years ago.

Not clear on what you're saying, but multiwire branch circuits (MWBCs) are still allowed per 2020 NEC Art. 210.4. By definition, they're two ungrounded (hot) conductors and a grounded (neutral) conductor, so only the current difference between the hots is carried by the neutral, just like service and subpanel feeder (including 50A RV) conductors.

Handle ties are required so all ungrounded conductors are deenergized at once when manually operated (120V-only loads) or a 2-pole common-trip breaker for 240V or 120/240V loads so an overcurrent condition on either ungrounded leg opens both poles.

Three-phase can also have MWBCs, but that's not something you'll find at home.

[wamcneil]

Wow. 4 pages of this... maybe time to stop beating this dead horse?

[jtrjr]

Just went through through "The great freeze of Texas" outside of Houston. Fortunately, in September, I set up a generator for my whole house through the main panel. It worked flawlessly and ran our whole house including the pool. Great care must be used to do the install properly and with the right equipment/parts. Doing a hack job could cause death, injury, property damage and loss. My generator choice was a Westinghouse Wgen9500. 12.5k starting watts, 9.5k running watts. I got the gen for about $900 and the parts to do the job properly ran me another $500ish.

[56glasspar]

You need a transfer switch. Reliance makes all types, you can even buy one at Home Depot. https://www.homedepot.com/p/Reliance...6HDK/202213700

Here is a link to Reliance sight Products - Reliance Controls Corporation