Simple Generator Whole House Hook up.

Started by Raptor, July 27, 2021, 08:03:27 PM

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Raptor

Let me start by saying that this setup may not meet electrical codes in some areas however it will be safe to use if used properly.

Several years ago I bought a small garden cottage for my wife. There is a modest 1,200 sq ft one bedroom 1 bathroom home on 3 acres near the farm. It has a central HVAC that uses only 20 amps 240 volt. It has a propane heater, stove, oven and tankless water heater. There is a well pump and washer & dryer, all 240 volts. However with only 30 amps at 240 volts there is ample power for the basic necessities refrigerator, HVAV and lights. The well pump and dryer can be run alternatively if needed. 

When I bought there were some minor electrical issues nothing major but I needed to pay an electrician to drive 1 hour each way out to the woods to get some work done. So I decided to add a few things to the list. One of them was 240 volt 30 amp "RV plug". This was both to allow a friend to park an RV there and more importantly a generator hook up in the event one was needed. I have several generators and I keep 6.5 kw gasoline one nearby. That one can provide ~30 amps @ 240 volts.

The set up does not have an automatic transfer switch and in fact has no transfer switch at all. It relies upon manually making sure the main breaker is turned off to prevent back feeding to the utility provider and injuring or killing a line man. If this statement does not make sense then do not use this method and have an electrician install a transfer switch.

Back feeding is both illegal and hazardous and needs to be avoided. You will also see people plug a 50 amp 24 line into a dryer plug to achieve this. Do not do this. Instead this method feeds into the main panel and energizes the circuit in the same manner as the main utility. Just make sure the main breaker is off and check it twice before energizing the panel.

You may ask why only 30 amps and not 50 amps. I made sure the wiring from the inlet was sized for 50 amps but decided on 30 amps because it was adequate for my needs and I did not want to push the envelope.

I mentioned the electrical work needed. These picture are the ones I gave to the electrician. The first thing needed was a main circuit shut off and I had him install a 200 amp main breaker and test to ensure that once the breaker was off all power flow between the main panel and the utility was indeed off.

If you notice in the diagram there is an Auxilary panel with both 120 and 240 volt breakers. I wanted an additional 30 amp 240 breaker installed to connect to the 240 volt outlet. This outlet uses a recessed male L14-30 plug.

The process is simple.
1. Turn off main 200 amp breaker. Verify that is off. Double check it.
2. Turn off all other breakers.
3 Connect the generator to panel with a 30 amp cord and appropriate plugs and start it.
4. Turn on the generator inlet plug circuit breaker. Use a multi tester to assure there is power being fed into the panel. 
5. Once again very carefully verify with a multi-tester at utility side of the main breaker that power is NOT back feeding. Seriously it is that important.
6. Then and only then should you turn on the breaker for item you want to use.
7. Depending upon the panel you may want to verify no back feed at the utility side of the main panel.

Power management is required and if you draw more than 30 amps the circuit break will trip.

I have to date not used it for generator except for the initial testing. I have used it to plug in a friend's RV.

The total cost of this was minimal. It was about an hour of labor and about $125 in parts and wiring. That said obviously the electrician was coming out anyway and I had a sunk cost of pre agreed upon 8 hours of labor of which 2 hours was travel time.

There are other cost effective ways to hook up a generator to a house without power cords. This is but one way to do so.

When power is restored turn off the generator and trip the generator in breaker and turn on the main power in breaker.

   



 
Folks you are on your own...Plan and act accordingly!

I will never claim to have all the answers. Depending upon the subject; I am also aware that I may not have all the questions much less the answers. As a result I am always willing to listen to others and work with them to arrive at the right answers to the applicable questions.

sheddi

Quote from: Raptor on July 27, 2021, 08:03:27 PM
When I bought there were some minor electrical issues nothing major but I needed to pay an electrician to drive 1 hour each way out to the woods to get some work done. So I decided to add a few things to the list. One of them was 240 volt 30 amp "RV plug". This was both to allow a friend to park an RV there and more importantly a generator hook up in the event one was needed.
...
I wanted an additional 30 amp 240 breaker installed to connect to the 240 volt outlet. This outlet uses a recessed male L14-30 plug.

Very ingenious, raptor, thank you for sharing.

I have one question if you don't mind. I see the Generac input is a plug (albeit one with recessed pins). I guess your RV friend needs a socket-to-socket hookup cable? Are these pins live and potentially accessible when running on grid power, or do you keep that breaker open except when the input is in use?

Raptor

#2
Quote from: sheddi on July 28, 2021, 04:00:35 PM
Quote from: Raptor on July 27, 2021, 08:03:27 PM
When I bought there were some minor electrical issues nothing major but I needed to pay an electrician to drive 1 hour each way out to the woods to get some work done. So I decided to add a few things to the list. One of them was 240 volt 30 amp "RV plug". This was both to allow a friend to park an RV there and more importantly a generator hook up in the event one was needed.
...
I wanted an additional 30 amp 240 breaker installed to connect to the 240 volt outlet. This outlet uses a recessed male L14-30 plug.

Very ingenious, raptor, thank you for sharing.

I have one question if you don't mind. I see the Generac input is a plug (albeit one with recessed pins). I guess your RV friend needs a socket-to-socket hookup cable? Are these pins live and potentially accessible when running on grid power, or do you keep that breaker open except when the input is in use?


That is a standard plug for a generator hook up. Those pins are not not really exposed but rather recessed and there is a cover; but yes I keep the breaker off because that scares the hell out of me too.
This is a standard US generator cord with a male and female l-14 30 plug that the plug was designed to accomodate
https://www.homedepot.com/p/Champion-Power-Equipment-25-ft-NEMA-L14-30P-to-L14-30R-Generator-Cord-in-Yellow-100395/30370004.

Over here most RVs have a 30 or 50 amp 240 volt inlet with a similar shore power arrangement. It is plugged into the RV with a female 50 amp 240 volt plug and the other male and plugged into the power outlet. So you need a pigtail adapter with two female ends to make it work for that purpose. Ready made pigtail adapters with female plugs at each end are available or you simply make up your own. In this case the guy brings his own.

I could have just as easily put both a male and female weather proof plug and run it off the same breaker but the intent was for a generator inlet.






Folks you are on your own...Plan and act accordingly!

I will never claim to have all the answers. Depending upon the subject; I am also aware that I may not have all the questions much less the answers. As a result I am always willing to listen to others and work with them to arrive at the right answers to the applicable questions.

sheddi

Thank you Raptor, that all makes sense.

Over here the usual RV or generator hookup is a 16A IEC60309 connector (AC is rare on British RVs and heat is generally from propane or diesel so electrical demands are relatively low).

Outlet:


Inlet:


Inlets are pretty rare (except on RVs, refrigerated vehicles or dedicated generator hookups like yours).

Raptor

If you provide a free parking spot in the woods with power and water available to an RV'er they will figure out some way to hook up to it. :clownshoes:

Quote from: Raptor on July 28, 2021, 04:53:17 PM
In this case the guy brings his own.

Folks you are on your own...Plan and act accordingly!

I will never claim to have all the answers. Depending upon the subject; I am also aware that I may not have all the questions much less the answers. As a result I am always willing to listen to others and work with them to arrive at the right answers to the applicable questions.

Johan

Thank you Raptor for the writeup!!
(Excellent as always)😀
It got me thinking!!

Firepower...
-Is One Bullet that Hits!!!

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