AC ammeter in caravan

Discussion in 'The Projects Forum' started by mike68, Apr 20, 2011.

  1. mike68

    Thread Starter New Member

    Apr 20, 2011
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    0
    Power facilities available on caravan sites can vary between 6-16amps and if exceeded trips the supply. Thinking of fitting a 0-20amp AC ammeter in series with 240volt supply in my caravan. Found a digital meter (requires a 12dc supply) complete with 20amp shunt.
    Would like to know if this sounds okay and should the dc supply to the meter be fused ?What kind of volts drop across the shunt should I expect ?
    Many thanks in anticipation
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Your camel won't like that. But maybe you mean a Dodge caravan?

    What in the world are you trying to do? Please specify the power source you want to use, and the load you want to power. Then you'll get less flippant answers.

    And Welcome to the AAC Forum!
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Mike may be from the UK or Downunder. "Caravan" in the Kings' English means "Trailer" in American English.

    Just wait for him to borrow a pint o'petrol and a spanner to open the bonnet and prime the carby.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Ah, that makes sense.

    In that case, I think what the OP needs is an inductive pickup approach instead of the shunt-plus-voltmeter approach. Maybe a Kill-a-watt?
     
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Yes, in the UK a caravan generally means living accommodation of a kind which (in principle at least) can be towed behind a vehicle. Motor caravans are a similar concept, but able to move under their own power.

    On the whole, I would not be too sure of using a 20A meter shunt permanently in a mains line, as some are not continuously rated. Even if it is, it may not have the sort of overload rating needed to cope with likely fault currents. You can probably bet your insurer would not like it.

    Any meter connected to it would also be permanently "live", a consideration especially if there might be kids about.

    Something like a current transformer might be better, if you can pick one up cheaply. This would have the advantage that your meter would be isolated.
     
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  6. mike68

    Thread Starter New Member

    Apr 20, 2011
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    Many thanks for the welcome.What I would like to do is monitor the current,so that if drawing close to the protected supply I can switch off some of the appliances.AC load varies as to what is switched on up to a maximum of 16amps.dc load would be the meter.
    Hope this is a little clearer.
     
  7. Adjuster

    Well-Known Member

    Dec 26, 2010
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  8. mike68

    Thread Starter New Member

    Apr 20, 2011
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    0
    Yeah that is excellent only downside is accessibility.Incoming power is under furnishing and into PSU. What I would really like to use is a miniature panel mounted instrument supplied with a (as you stated previously)current transformer. And the downside of that maybe the cost.
    Amount of mains equipment in recreational vehicles is constantly growing so need to try and keep a control.
     
    Last edited: Apr 20, 2011
  9. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Disassemble a clamp-on ammeter and extend the wires from the pickup coil to the meter section. Place the meter where ever you please. Full isolation. Or find one of these units designed to be connected to a Simpson 260 VOM.
     
    Last edited: Apr 20, 2011
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