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Halffull's avatar
Halffull
Explorer
Jun 18, 2017

Onan output wiring

I have a 6500 w Onan with 2 - 120 v 30 amp breakers. Is it possible to run the two legs to an electrical panel, then to a 240v to 120v step down transformer? My question is for two reasons. With only one leg being loaded, it seems to me that it's putting uneven pressure on the generator, and also the one breaker being used sometimes trips if the inverter is doing a bulk charge on the battery bank AND another heavy load kicks in.
  • sure wish i could get a look at the wiring diagram

    IF that is the one i am thinking of you will read ZERO or near ZERO across hot lead leads 1 & 2 going to the (2) breakers

    the generator is capable of 120v 54 amps, but you are trying to pull to much from one 30a breaker

    IF it measures zero across the hot leads and 120v from each hot to neutral
    you should be able to connect the hots to together with (1) 50amp breaker

    the problem is me doing something i know how to test for and do correctly
    and telling somebody else its OK ?

    the hgjab-904 is an emerald microlite belt drive, not the model i'm thinking about
    still if its zero volts across the (2) breakers
    you should be able to replace with a single 50 and connect them together
    as the are already connected internally
    and that is key to the whole thing
  • Chris Bryant wrote:
    According to the ***Link Removed***, the HJGAB-904 is 120 volt only.
    Any way you can separate the other loads while on generator?


    All loads are fed by the battery bank/inverter. 75% of the time, the solar panels/batteries/inverter supply is sufficient to meet the load demands. Only over a period of heavy overcast days and/or when utilizing higher demand equipment does the generator get started. So separating out loads would be onerous and entail running much more cabling not to mention having to start the generator for some loads but not others. I guess my last question is: is there any way to take advantage of the 2 - 30amp breakers or are the two legs never to meet?

    Thanks for you input.
  • MrWizard wrote:
    sure wish i could get a look at the wiring diagram

    IF that is the one i am thinking of you will read ZERO or near ZERO across hot lead leads 1 & 2 going to the (2) breakers

    the generator is capable of 120v 54 amps, but you are trying to pull to much from one 30a breaker

    IF it measures zero across the hot leads and 120v from each hot to neutral
    you should be able to connect the hots to together with (1) 50amp breaker

    the problem is me doing something i know how to test for and do correctly
    and telling somebody else its OK ?

    the hgjab-904 is an emerald microlite belt drive, not the model i'm thinking about
    still if its zero volts across the (2) breakers
    you should be able to replace with a single 50 and connect them together
    as the are already connected internally
    and that is key to the whole thing


    AH! Ok, now you're talking the language of my good friend. I'll pass your post along to him and get him to do the analytics next time he comes in to do some fishing.

    Thank you very much.
  • MrWizard wrote:
    sure wish i could get a look at the wiring diagram

    IF that is the one i am thinking of you will read ZERO or near ZERO across hot lead leads 1 & 2 going to the (2) breakers

    the generator is capable of 120v 54 amps, but you are trying to pull to much from one 30a breaker

    IF it measures zero across the hot leads and 120v from each hot to neutral
    you should be able to connect the hots to together with (1) 50amp breaker

    the problem is me doing something i know how to test for and do correctly
    and telling somebody else its OK ?

    the hgjab-904 is an emerald microlite belt drive, not the model i'm thinking about
    still if its zero volts across the (2) breakers
    you should be able to replace with a single 50 and connect them together
    as the are already connected internally
    and that is key to the whole thing


    I metered the leads this morning and as you suspected, the unit has 120v across the hot leads and neutrals and zero across the two hot leads.
  • You are good to go
    Just make sure that you also use both neutrals, that they get connected together (you did say neutrals, plural)
    And the two hots together feeding one 50 amp breaker

    Don't want to have just one neutral trying to carry the full return circuit load
  • MrWizard wrote:
    You are good to go
    Just make sure that you also use both neutrals, that they get connected together (you did say neutrals, plural)
    And the two hots together feeding one 50 amp breaker

    Don't want to have just one neutral trying to carry the full return circuit load


    Yes, 2 hot leads, 2 neutrals and one ground. Thanks very kindly Mr. Wizard, much appreciated.
  • One more test
    Check hot #1 to neutral #2
    Hot #2 to neutral #1
    Make sure those readings are 120v

    Or maybe you already did

    This will verified they are already connected together
  • MrWizard wrote:
    One more test
    Check hot #1 to neutral #2
    Hot #2 to neutral #1
    Make sure those readings are 120v

    Or maybe you already did

    This will verified they are already connected together


    Finally had a minute to do your recommended confirmation test. Result: Both hot leads crossed with both neutrals result in the same 125 volt ac reading.

    Thanks again sir, looking forward to not tripping the 30amp breaker.

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