RV generator - wire into house

[Shran]

I obtained an Onan Emerald 1 generator yesterday. It came out of a mid 80's motorhome that my buddy is tearing apart. I haven't heard it run yet but I imagine it'll be no problem to get up and running and it only has about 550 hours on it.

I'm tempted to set this thing in place permanently and wire it into my house - I believe it's 4000 watts so that should easily run my gas furnace and a couple other small appliances. I'm familiar with the wiring part (transfer switch and such) but I need some feedback about a couple other things:

Enclosure: thinking about building some sort of enclosure for it. Not really "weatherproof" or whatever, just something to keep it relatively dry. I am thinking about some sort of box that it can sit in. Up off the ground, probably with an angled "roof" and maybe fuel/battery storage under or next to it.

Exhaust: the exhaust port is on the bottom of this thing. I have the exhaust system and muffler from the motorhome, will need to be modified... thinking run it down, out the side of the enclosure, then angled out 90 degrees?

Fuel storage: will need some sort of container. I have a plastic 11 gallon fuel cell, I could mount that under it... exhaust concerns though? Maybe above would be safer? Mount the starting battery below? The generator has an electric fuel pump so I am flexible with mounting location.

Pardon the crude drawing but this is kinda where I would like to put it. I have very easy access to my breaker panel (red arrow) through my crawlspace. The red box thing is my enclosure, green line is the exhaust, green box is the generator itself, yellow line is the power feed from the gen to the breaker box.

Thoughts?

 

[RonD]

I wouldn't do gas tank or battery above it, fire goes UP, lol
Try next to it and make cover wider
And remember how ever you set it up you WILL need to service it, we all complain about what a pain it is to service some engine parts in our Rangers.................well don't do that to yourself if you don't need to

Its rated at 120vAC 30amp which is 3,600watts so its called 4,000watts
One thing you need to consider if it will be powering an electric motor, like a furnace fan/blower, these have higher Start Up amps, so every time the motor starts there will be a spike in amp draw that you need to factor in so its not tripping the 30amp breaker at the genset
8amp motor can draw 25-30amps for the first 3 seconds of start up

 

[Dirt Squirt]

Also keep in mind it is an air cooled engine. Needs air flow.

 

[Shran]

Thanks guys.

Fuel storage next to it might work. Or maybe behind. I'll have to do some measuring. I have kind of a narrow spot to put this without overlapping my crawlspace access hole, which is why I was thinking of putting the tank above or below. Good point about fire going up. I was more concerned about the exhaust port point down if I had the fuel below...and I'd have to run the exhaust above the tank then.

I'll check the blower motor on the furnace. I am fairly certain the furnace is only on a 15 or 20 amp breaker in the house so I figured it would be OK. Definitely not going to try to run the whole house on the generator, I might actually just wire it straight into a dedicated transfer switch for the furnace. Keeping the house warm and maybe running one small freezer is my main objective here.

Service/airflow: definitely will keep that in mind. Oil drain, fill/oil filter, one spark plug, air filter, fuel pump and carb are all very accessible right on what will be the front facing outwards so that's nice. Only one spark plug and the coil will be on the back side.

I was planning on having louvers or vents in the enclosure and probably leaving the bottom open or very close to it. In the motorhome it was basically in a 5 sided metal box that was open on the bottom and had a small vent on the access door...really not much airflow, whatever I come up with will be an improvement on that.

This is kind of one of those "why not" projects, the generator itself has only cost me a couple hours of time to remove it so far and it would be really nice to have backup power at the house.

 

[DILLARD000]

At 3600w 120vac, you'll only be able to power up one side of a typical split phase 220\110v domestic panel,
& every time your fridge\freezer compressor kicks on, this 3600w will bog down & the system voltage will take a dip.
This 120v generator will not power up a 220v well or 220v furnace fan.
I wouldn't not try to power up a typical domestic 240v panel with less than a 8kw rated gen set;
average household load runs 1kw~1.5kw, but motor starting inrush is what a gen set needs to be up sized for.

Best to have gen set in a seperate walkaround fireproof well ventilated enclosure at least 4~5ft away from the house.
If generator decides to go up in flames, don't want the house to burn down, & don't want exhaust carbonmonoxide poisioning.
Check your local city\county for code requirements.

 

[Shran]

Kind of rethinking this idea. It's a lot of work to build a dedicated enclosure for an old generator... I think I'm going to build a cart and have it be somewhat portable instead. It is very heavy though.

I did get it running on the bench this evening. I was shocked that it damn near fired right up and ran great and makes power... I'm used to old equipment needing a carb kit right away.

Beings that I know it makes power brought up another interesting point. It's got the typical white, black and green wires coming out of it... But when I measure across the black and white I get 230v. So it looks like black and white are both hot? What makes neutral here, the ground? How do I get to 110v, Black or white and ground?

 

[Curious Hound]

Kind of rethinking this idea. It's a lot of work to build a dedicated enclosure for an old generator... I think I'm going to build a cart and have it be somewhat portable instead. It is very heavy though.

I did get it running on the bench this evening. I was shocked that it damn near fired right up and ran great and makes power... I'm used to old equipment needing a carb kit right away.

Beings that I know it makes power brought up another interesting point. It's got the typical white, black and green wires coming out of it... But when I measure across the black and white I get 230v. So it looks like black and white are both hot? What makes neutral here, the ground? How do I get to 110v, Black or white and ground?

It would be best to find a manual for it to see the recommended connections. You may get 110v by connecting from one hot leg to ground. Or it may have been designed to only make 230v. If that's the case, you would need a transformer that would allow you to "tap" the center of the secondary winding to get 110v (half the voltage). You really need the specs on the machine to know how it is wired internally.

 

[09fx4guy]

I have been thinking about something similar for my house, some way that I could connect my portable generator to my house without a myriad of extension cords.

I would honestly go with your idea of making it portable. You can also maybe build a smaller 4x4 covered box (without sides) so you can use it in the rain. For my generator, I have one of those larger plastic outdoor storage boxes. I leave the doors open with the exhaust pointed out so it is at least covered from potential rain.

I would hesitate to put the generator that close to the house, especially under a window. Between the exhaust and the gasoline fuel cell, it could be trouble.

As I recall, they do make a transfer switch (Generac I think) where you could use a 25ft electric cord that you could plug into the generator and then plug into the house switch.

Just keep researching, get as much info as possible before you start your project.

 

[Fast Eddie]

Kind of rethinking this idea. It's a lot of work to build a dedicated enclosure for an old generator... I think I'm going to build a cart and have it be somewhat portable instead. It is very heavy though.

I did get it running on the bench this evening. I was shocked that it damn near fired right up and ran great and makes power... I'm used to old equipment needing a carb kit right away.

Beings that I know it makes power brought up another interesting point. It's got the typical white, black and green wires coming out of it... But when I measure across the black and white I get 230v. So it looks like black and white are both hot? What makes neutral here, the ground? How do I get to 110v, Black or white and ground?

All goood advice above. Neutral is black, white is hot EDIT: Black is hot, white is neutral and green is ground. I would be very surprised if it put out more than 110@30A. Knowing the coach it came out of would help there.




Excerise the gen once a month with no less than 50% load. Take a crack at this and digest it: https://onan.xmsi.net/940-0502 Onan NHE-NHEL (spec A-C) RV Genset Service Manual (07-1987).pdf and look for this:

 

[DILLARD000]

For household AC,
Green/BareWire=Ground,
White=Neutral,
Black/Red=110/220v.
Per NationalElectricalCode/NEC.
This is notably different from automotive DC color codes.

 

[Snoranger]

My neighbor has a DIY transfer switch...
50 amp breaker wired to a 50 amp outlet. He shuts off the main breaker and anything he doesn’t want to power. He plugs a homemade male to male extension cord in to the outlet and his generator. Then turns on the 50 amp breaker to back feed the remaining circuits.

 

[RonD]

Yes, you buy or make an interlock for your breaker panel
Basically you can't turn on the breaker connected to generator unless the Main has been switched off

Looks like these: https://interlockkit.com/

 

[Fast Eddie]

You should have some type of interlock device or ATS in place. Your generator can energize external supply lines (e.g. the backfeed @snoranger mentioned). If lineman are working on downed lines and your generator energizes the lines - even though the power comppanyv 'thought' they disconnected it - a lineman could get hurt, or worse.

 

[StokdGS]

Yes, you buy or make an interlock for your breaker panel
Basically you can't turn on the breaker connected to generator unless the Main has been switched off

Looks like these: https://interlockkit.com/

I know this is way late, but just wanted to say that when I lived in the Pacific Northwest for 11 years, we had bad snow that knocked down power lines for sometimes weeks at a time every year.. So, I bought an 8,000 watt, 13,500 starting watt generator, had 2 Square D breakers installed at the top of the power panel - 1st one connected to the Meter, and it was the type of breaker that had to be closed, before it would allow the 2nd breaker to engage On..
The 2nd Square D breaker was wired to an external weatherproof outlet, just outside the garage, and the generator was plugged into that outlet when I needed it to run 24/7 for those few weeks we were out of power... I had the entire panel running off this, and never had an issue once in all those years.. The extension cord from the generator was Carol Cable nbr 10/4 huge, heavy duty with 4-prong heavy duty twist lock connectors at each end.. The cable ends were rated for 30 amps.. I found a really nice small, gray, Rubbermaid plastic shed at Home Depot that was the perfect size to house the generator outside all year, protected from all the rain, snow, etc., and I just opened the 2 doors when I ran it inside that nice shed for those weeks, and never had an issue..
We tried to mind what we were doing inside the 3,700 square foot house during those weeks, and I had to buy around 11 gallons of gas for it before winter every year...
We were one of the very few houses in our neighborhood that was warm in winter when this happened, so we had lots of neighbors come by to get warm and take a hot shower, etc., and that was great.. We were happy to help !
All the other really rich people down the street just left their cold houses and checked into a nice hotel for the duration or went to Maui or something until we all got power back...
I learned a lot about all of this... Like I never knew the Meter is actually just a giant twist lock Breaker itself, and comes off like unscrewing a giant light bulb.. But you have to do that to be absolutely safe when you have to move all the breakers in the 200 amp panel down a couple of slots, to put in the generator breaker/shut off arrangement...
Hope you were able to get yours figured out a long time ago !