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Onan 20es spec 79794G set up help

CenTexBear

Registered
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Thanks in advance for the help. I’ve been looking through other Onan posts and it seems like there is an over abundance of knowledge on this site over some others so I’m coming to the feet of wisdom.
I just purchased this Onan 20es spec 79794G. It came off of a small medical facility and was set up as a standby system. I didn’t get any of the standby control system. I’ve been trying to determine how far this will push 3phase. My plan is to connect to mine and my parents houses, obviously only for essentials in each house, which are about 400ft apart. DoI need to place the gen at a mid point and run wire both directions, or can I put the gen at one house and run one direction? I will be feeding the unit with 1” from a 500gal tank.
 

Birken Vogt

Email NOT Working
You got a good generator if it is in good shape.

This is a job for an electrician who is experienced in generators. It is not a DIY project.
 

CenTexBear

Registered
You got a good generator if it is in good shape.

This is a job for an electrician who is experienced in generators. It is not a DIY project.
I will be the first one to back away from electrical work. I am not trying to wire it in. I am trying to figure out where I need to place the gen set so that I can have someone wire it in. Can anyone tell me how far it will push electricity?
 

Wayne 440

Registered
A generator does not "push" electricity any certain distance, it is an essentially constant voltage source . The distance from the generator to the point of use and the anticipated load determines the size of the required wiring. There are a number of other factors besides the wiring path(s) and expense that should be considered when placing the set. Distance from the fuel source, ease of service access, noise and exhaust fumes are a few. You almost certainly need on site advice from a person with installation experience if you wish to have a reliable, well functioning installation.
 

CenTexBear

Registered
ok I've got another question. I switched it over to Gasoline today and tried to start it. The ignition switch in this particular unit is a three stage switch with "remote" "Stop" "Start" positions, It had a standby system on it previously. When in the remote position you can hear a relay in the board trying to engage, but when you push and hold in the start position nothing happens. Is there supposed to be a wire going from the battery to the ignition switch or something?
 

zuhnc

Subscriber
Last Subscription Date
12/08/2019
All the Onan Guru's are on the Onan board. They can answer any questions you have as to the capabilities of the generator. Search the forum for Onan generators. For your residential applications, you should reconnect the set for 120/240, single phase. This gives you a full 83 amps output. This set is capable of 20KW at 120/240, single phase. Most likely it is connected for 120/208, 3-phase, now. Unless either of your residences use 3-phase, reconnection for single-phase is the desired output. zuhnc
 

GADavis

Registered
Age
80
I have a 1996 model ES 20 unit like yours, running on natural gas that I changed from LP. It is only about 50 ft from the transfer switch in my set up. This is a very smooth running quiet unit that is dependable. With the covers all in place it is little more than a humming sound using the stock top mounted muffler. You need to find a manual for this unit. Go to the Onan board and they will know where to find a down loadable one , The ES in the model stand for Extended Stack which I think is supposed to mean it can produce the rated Kw 's in either 120 or 240 , 1 ph or 3 ph configuration. For the 50 ft distance I used 2/0 copper stranded cables with a # 6 ground wire. I prefer to err on the large size for this. My generator is configured for 240 single phase. Higher voltage transmits better with less loss for distances. I would think that you could find the wire size needed for the distance on a reputable website that deals with wire and sizes. I installed mine myself but paid a local electrical contractor to do the last connections and sign off/certify the installation so the insurance company could not wiggle out of a claim if there was a fire. I really like my unit. There are some very sharp generator minds on the Onan board. Along with the 20 ES manual down load you need a T-105 gaseous fuel manual also.


Gene Davis Tennille, Ga.
 
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