AC/DC Clamp Meter Altitude Limit

I'm putting together my toolkit and just got an AC/DC clamp meter. While reading the instruction booklet (since my identity is a secret I can admit that :D) I noticed that there is an altitude operating limitation of ~6500 feet. The property I have where the solar installation will be is at ~7500 feet. Any ideas why this type of meter would have such a limitation and what problems or skewed readings might occur if operated above the listed limitation?


  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: AC/DC Clamp Meter Altitude Limit

    I can't imagine it making enough differenct to be significant, but I await more learned opinion with anticipation.

  • mike95490mike95490 Solar Expert Posts: 8,757 ✭✭✭✭✭
    Re: AC/DC Clamp Meter Altitude Limit

    It most likely has to do with the high voltage range of the meter, where they rely on air, as the insulator. Maybe for the current shunt, where air needs to cool it. At less than 100v, I don't see how it can make much difference, unless the LCD display dries out.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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    gen: ,

  • boBboB Solar Expert Posts: 975 ✭✭✭✭
    Re: AC/DC Clamp Meter Altitude Limit

    This has to do with decreasing breakdown voltage with decreasing atmospheric pressure, up to a point, that is, where it starts to reverse.

    Search for Paschen’s Law and curve.

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