Grid tie Down, Installer coming tomorrow

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solar_dave
solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
in Grid Tie and Grid Interactive Systems #1
OK so we had a grid outage today for about 2 minutes, the first in months and months.

The inverters are in some undocumented fault condition. Looks like line voltage may be an issue. Here is what I checked

1) the bus bar on the panel where the solar attaches shows 121 V on each leg & 244 across the 2 legs. Should be good there.
2) with the breaker in the on position same kinds of numbers off the breaker lugs. Should be good there.
3) next stop is the AC disconnect, Locked by Utility, no access :confused: (noticed the flex tight connector out the bottom is now just hanging loose.)
4) next stop is the PV meter with a utility seal on it, no access :confused:
5) next stop is the AC combiner where the 2 inverter outputs are combined. With both 30 amp breakers for the inverters off, Badness here, each leg of the bus bar measures 121 V to neutral, across the legs 0 volts. That sounds UGLY!

How can that be happening without a major short that should cause a breaker trip someplace.

Now turn on one or the other 30 amp breaker and the Inverter red and green led flash on and off, no panel display. It just moves with what ever 30 amp combiner breaker is on.

Now turn both 30 amp breakers on still only one has flashing LED but the other inverter appears DOA. Should be good there.

The Installation company electrician is showing up in the AM early. How should I make them diagnose this issue?
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
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    Re: Grid tie Down, Installer coming tomorrow

    you shouldn't have to tell them how to diagnose the issues as it is their job to find a problem and fix it. you can help them by saying what you had observed so that they have an idea where to start looking. i am not going to speculate on the problem as it could be a few possibilities. let them find the problem and make it right for you. good luck and let us know what they find.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
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    Re: Grid tie Down, Installer coming tomorrow

    The DC input does not sound correct... Depending if you have the negative or positive ground jump (solar array safety grounding)--One lead should read "Hot" with respect to the other array lead AND to the earth ground.

    If both leads read hot--that would indicate that either the 1 amp GFI fuse has blown or you have lifted green wire between the main panel and the inverters GFI ground (see PDF manual).

    If the GFI fuse blows--You need to find the failure point, fix and replace the fuse.

    It also appears that after the GFI fault has been fixed--there is still some sort of start-up/reset procedure that the installer needs to do (factory procedure to reset the GFI fault memory?).

    The output voltage being 120 VAC to ground/neutral, but 0 volts between L1 and L2 (when the breakers are off?)--May be just a little leakage current coming in capacitive coupling on one of the lines (or possibly some other electrical connection). If you are getting 120 VAC to ground and 0 VAC with only one breaker turned on at a time--that is probably normal.

    I am a bit confused about the ability to turn (it sounds like) L1 or L2 30 amp breakers individually--Normally, they are ganged together so that if one Lx leg trips a breaker, the other leg is shut down too.

    My guesses/inspection points.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #4
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    Re: Grid tie Down, Installer coming tomorrow
    BB. wrote: »
    The DC input does not sound correct... Depending if you have the negative or positive ground jump (solar array safety grounding)--One lead should read "Hot" with respect to the other array lead AND to the earth ground.

    If both leads read hot--that would indicate that either the 1 amp GFI fuse has blown or you have lifted green wire between the main panel and the inverters GFI ground (see PDF manual).

    If the GFI fuse blows--You need to find the failure point, fix and replace the fuse.

    It also appears that after the GFI fault has been fixed--there is still some sort of start-up/reset procedure that the installer needs to do (factory procedure to reset the GFI fault memory?).

    The output voltage being 120 VAC to ground/neutral, but 0 volts between L1 and L2 (when the breakers are off?)--May be just a little leakage current coming in capacitive coupling on one of the lines (or possibly some other electrical connection). If you are getting 120 VAC to ground and 0 VAC with only one breaker turned on at a time--that is probably normal.

    I am a bit confused about the ability to turn (it sounds like) L1 or L2 30 amp breakers individually--Normally, they are ganged together so that if one Lx leg trips a breaker, the other leg is shut down too.

    My guesses/inspection points.

    -Bill

    It is a mini sub panel with 2 ganged (240v pair) 30 amp breakers one for each inverter. the bus bar then feeds the meter --> disconnect --> and 60 amp main panel breaker.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #5
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    Re: Grid tie Down, Installer coming tomorrow
    niel wrote: »
    you shouldn't have to tell them how to diagnose the issues as it is their job to find a problem and fix it. you can help them by saying what you had observed so that they have an idea where to start looking. i am not going to speculate on the problem as it could be a few possibilities. let them find the problem and make it right for you. good luck and let us know what they find.

    Thanks Neil but their track record isn't the greatest. I was just hoping to get a couple pointers from the clan of the knowledgeable here. It just seems illogical that the bus bar at the AC combiner sub panel looks so weird.

    The data I did get was from a walk through by phone with the engineer @ the Installer company.
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #6
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    Re: Grid tie Down, Installer coming tomorrow

    Well, if there is such a thing as a good day to have you solar down, I guess today is it. Not much sun yet. Hope it is something simple like a bad breaker or loose wire.

    My utility locked the solar disconnect when I installed the second inverter. The meter guy said they were concerned about the live terminals when opened. That Square D disconnect does not have an interlock on the cover.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
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    Re: Grid tie Down, Installer coming tomorrow

    Like I said, I have had less than stellar performance from them, still waiting on the electrician @ 1PM today, no call back. :cry:

    I may call APS this afternoon and see if I can get them to come out and unlock the disconnect so I can take a look and fix the flex tight connector that has loosen up. I am starting to wonder if that isn't where the problem is, perhaps one of the wires has pulled loose. I had house painters here doing hail repair about 10 days ago, and maybe they pulled on the conduit too hard.
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  • FreeWatts
    FreeWatts Registered Users Posts: 14 ✭
    #8
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    Re: Grid tie Down, Installer coming tomorrow

    Did they ever make it out?
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #9
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    Re: Grid tie Down, Installer coming tomorrow

    Got a call today. Coming this afternoon. I suspect a bad connection, Hoping anyway.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
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    Re: Grid tie Down, Installer coming tomorrow

    You guys are not going to believe this, it was the Square D master disconnect switch between the solar meter and the breaker panel. One leg of the 220 was not making a good connection, if not snapped in hard it failed to make proper contact.

    Electrician is talking to the main man at Installation Company to get it replaced and fix a couple other issues with the flextite garbage connectors used everywhere.

    Meter spinning backwards again! :D
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #11
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    Re: Grid tie Down, Installer coming tomorrow

    Good to hear it was something simple :)
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #12
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    Re: Grid tie Down, Installer coming tomorrow

    No offense intended, but I never understood why some solar installers have such a love affair with looping flex between two fixed objects on a wall.

    I have been less than impressed with Square D light duty switches, but the choices for an open blade switch are limited. GE TG and TH come to mind as a option other than Square D light duty.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #13
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    Re: Grid tie Down, Installer coming tomorrow
    Jburgess wrote: »
    No offense intended, but I never understood why some solar installers have such a love affair with looping flex between two fixed objects on a wall.

    I have been less than impressed with Square D light duty switches, but the choices for an open blade switch are limited. GE TG and TH come to mind as a option other than Square D light duty.

    Flex is a cheap fast solution, but I tend to agree. Even worse is the use of cheap plastic connectors on that flex, which if tightened properly tend to strip the threads holding to the box. I suspect the stripped flex connectors here may have been caused by the house painter fixing hail damage by moving the flex a bit to tape the boxes off. In any case I am after them to replace all the nasty plastic stuff and the Square D switch, something that has a 10-15 year life and already shows signs of connector and simple equipment failure doesn't bode well.
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #14
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    Re: Grid tie Down, Installer coming tomorrow

    Did your dealer make things right for you?
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #15
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    Re: Grid tie Down, Installer coming tomorrow

    Short answer, no. Looks like it will be either a self repair or hire an electrician.
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