Xantrex xw pro negative to ground voltage prsent

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mahendra
mahendra Solar Expert Posts: 181 ✭✭✭
in Advanced Solar Electric Technical Forum #1
Hi .
A friend of mine has a xantrex xw 6748 pro hooked up to a midnite epanel.
System is about a year old.
On  a recent check up it was observed that there is  34vdc present from the negative to earth.
Initially  it was though that this was comijg from the pv arrays but after isolation of all component it was noted that the inverter was the origin of this issue.
This voltage was tested coming out of the inverter even after it was turned off .It took however about an hour for this voltage to fall to zero.
I am suspecting a grounding issue since all components are functioning as normal.
Is my suspicion accurate or is this normal with the XW?
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  • mahendra
    mahendra Solar Expert Posts: 181 ✭✭✭
    #2
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    Ps i also noticed there isnt a dc negative to earth bond which i  suspecting is causing the issue.
    Just want to be certain its not so other issue.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,749 ✭✭✭✭✭✭
    #3
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    One of the problems with mixing equipment manufacturers is they will blame each other and the owner is in limbo.
     Midnite makes nice products but the same similar  panels from the OEM Schneider are what I use. This is what warranty is for and it avoids the finger pointing !!!

    This is not an XW problem and something is not wired correctly, or another issue is present. Use another meter to check, wiring to ground and consult the manuals. Check it again! 
     
     Friends don't. have DC voltage to ground!😉 Not understanding some of your post so post it again in a different way. 
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,749 ✭✭✭✭✭✭
    #4
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    Schneider Solar makes XW pro BTW.  Xantrex is an old friend :)
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #5
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    The typical DMM probably have a 1,000,000 Ohm resistance between leads when measuring voltage... You can have a little bit of "charge" on the battery bus offsetting the + and - leads with respect to ground. And it will not "discharge" that offset voltage (typically there are some capacitors somewhere in the system between +/- and Chassis ground that will hold enough charge for the meter to read.

    A quick and "safe" check is to use a ~40 Watt (or whatever) 120 VAC filament bulb and wire it between battery negative and your "ground".

    The bulb will not pull enough power/current to damage anything. And you you can now measure the voltage between "Ground" and battery negative bus. If near zero volts, then you are just seeing some "leakage" current (very small mAmps or even uAmps). if you still see close to 48 volts, then you have a "hard connection" between + and "ground"--Possibly a short, a "positive ground", or some random device connection.

    Can you tell us a bit more about the installation? Is this a vehicle/RV/Trailer, or a home? Does the home have a "ground" rod and or cold water bond and green/bare copper wire back to the AC main panel or AC inverter's output (ground bonded Neutral+Ground buses)?

    All the "electrical stuff" (epanel chassis, XW Chassis, AC Main panel, and any metal J-Boxes and Sub-Panels should all be tied to ground (conduit, green wire, and bare wire grounding).

    If there is a "ground" connection in the home/vehicle, that is were the battery negative bus/terminal should be tied (bonded) to "ground".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mahendra
    mahendra Solar Expert Posts: 181 ✭✭✭
    #6
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    Thanks the system is a mix system.
    Owner's choice.
    The inverter is xantrex xw hooked up to the midnite epanel as mentioned.
    With outback fm80 charge controller .
    Midnite solar pv array combiner 
    It is used strickly as an off grid system .
    It is not on a rv.
    It does have a grounding.

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  • mahendra
    mahendra Solar Expert Posts: 181 ✭✭✭
    #7
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  • mahendra
    mahendra Solar Expert Posts: 181 ✭✭✭
    #8
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    Unfortunatly i dont have a pic to show the wiring and wont be able to do so probably till in september.
    Its not a system that is being used  regularly .
    It runs a small refriderator and wireless internet so that a care taker can make contact with the owner.
    Not at an easay to access location as well.
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