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Voltage on one lead of solar panel/string

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  • Voltage on one lead of solar panel/string

    Can someone explain what the voltage on one lead (+ or -) of a solar panel/string is?
    Obviously testing voltage from one lead to the other is Voc.
    From experience, testing voltage from one lead to ground shows a small initial voltage which quickly dissipates to 0. Does this mean that touching the bare conductor from one lead of a panel (or string) presents no shock hazard?

  • #2
    Depends on the voltage level. OSHA has stated that anything below 50VDC is safe to touch and will not hurt someone due to the high body resistance between the voltage source and ground. But if you shorted out a 12V battery + and - terminal you would see fireworks that could burn or even kill you.


    • #3
      When you touch/measure voltage from one lead to the frame of an otherwise unconnected
      panel, you do not have a complete circuit. Therefore you will not be able to draw any
      continuous current. Connecting a very high input impedance voltmeter might give an
      initial reading of voltage but no current/power. This is caused by static charge or extremely
      small leakage of the insulation, charging minute stray capacity with a few electrons. The
      energy content is less than you get rubbing your feet on the rug.

      Most single panels do not develop enough voltage between leads to be dangerous. Strings
      of panels can be very dangerous, mine run at 400VDC. Bruce Roe