Newb Question: Wiring

SageBrushSageBrush Registered Users Posts: 19 ✭✭
edited June 2017 in PV Installers Forum - NEC, Wiring, Installation #1
I lost the marker I had placed on one end of my circuit wire to identify which direction the wire was placed in the ground, so I need a method to figure it out. Schematically I have this:

                           |  -----------------------|  (+)
Inverter    =====                              Serial Panels
                           | ______________| (-)

One end of my serial array will be + and the other end (-)
I need to identify which wire is which to know how to connect the wires to the correct terminals in the inverter.

Thanks!
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Comments

  • cow_ranchercow_rancher Solar Expert Posts: 117 ✭✭✭✭
    #2
    Hmmm try a VOM when the sun is shining, that should be a pretty good indication.

    Rancher
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  • LumisolLumisol Registered Users Posts: 374 ✭✭✭
    #3
    You could also use a wire tracer and tone generator.
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  • SageBrushSageBrush Registered Users Posts: 19 ✭✭
    #4
    Is a VOM the same as my $10 digital multi-meter from Harbor Freight ? :-)

    So in this scenario:
    The (+) lead from my first optimizer is connected to the (+) input of the multimeter
    The (-) lead from my last optimizer is connected to the (-) input of the multimeter

    The serial voltage of 12v (12 SE optimizers) would register positive ?
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  • littleharbor2littleharbor2 Solar Expert Posts: 1,985 ✭✭✭✭✭
    #5
    Yes, and if connected backwards you should get a negative, - , reading.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • cow_ranchercow_rancher Solar Expert Posts: 117 ✭✭✭✭
    #6
    SageBrush said:
    Is a VOM the same as my $10 digital multi-meter from Harbor Freight ? :-)
    Yes, VOM = Volt Ohm Meter
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  • SageBrushSageBrush Registered Users Posts: 19 ✭✭
    edited June 2017 #7
    Thanks very much everybody!

    I feel obliged to ask one last REALLY stupid question, since I don't want to fry my inverter ...

    Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ?
    I think so, since I checked positive and negative voltage values of a 3V battery of known labeled polarity, but I'd like some reassurance here ;-)


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  • nickdearing88nickdearing88 Registered Users Posts: 100 ✭✭✭
    #8
    SageBrush said:
    Thanks very much everybody!

    I feel obliged to ask one last REALLY stupid question, since I don't want to fry my inverter ...

    Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ?
    I think so, since I checked positive and negative voltage values of a 3V battery of known labeled polarity, but I'd like some reassurance here ;-)


    No, Red is usually positive and the Black should be connected to the COM port.
    Current system: 8-100w Renogy panels mono/poly, 2 strings of 4 panels in series - 24v 100Ah AGM Battleborn LiFePO4 batteries - Morningstar MPPT40 CC - 1500W Samlex PSW inverter
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  • BB.BB. Super Moderators, Administrators Posts: 33,313 admin
    #9
    Note that you have two settings for reading voltage.

    DC (solid / dotted lines) and AC (sine wave / wiggly line).

    Different meters when set to AC will read DC voltages differently. Some will read DC voltage (always positive or no sign, amplitude may be correct or too high), other meters will read DC voltage as zero volts.

    When set to read DC volts, reversing leads should switch between + and - readings.

    - Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • littleharbor2littleharbor2 Solar Expert Posts: 1,985 ✭✭✭✭✭
    #10
    Typically the black lead would connect to the common port and red to the others. It would make no difference in how your meter reads if the other way around as long as you know which is which

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • mvasmvas Registered Users Posts: 395 ✭✭✭
    edited June 2017 #11
    With DC Volts  ...
    Red   is (+) Positive / Hot
    Black is (-) Negative / Common 

    Here is a picture of the "correct" way ...


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  • AguarancherAguarancher Solar Expert Posts: 315 ✭✭✭
    #12
    'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..
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  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited June 2017 #13

    Aguarancher said:
    'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..
    Just what I was thinking, 750W is high voltage?  Thought  >1000 VAC  was considered high voltage, as per IEEE, but that is debatable, so no argument there.. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • mvasmvas Registered Users Posts: 395 ✭✭✭
    edited June 2017 #14
    Aguarancher said:
    'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..
    The OP asked,
    "... Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ? ..."
    The question was "HOW to connect the Red & Black Probes to the meter".
    The picture shows the correct way to do that.
    It is a "stock photo", turn the Dial to the correct AC/DC Range, as need.

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  • AguarancherAguarancher Solar Expert Posts: 315 ✭✭✭
    edited June 2017 #15
    With the confusion the OP was expressing I was merely pointing out that your pic while showing correct positioning of the leads was showing AC and not DC voltage as he was requesting. This pic shows both in the correct position.
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