208V L1 & L2 currents

Discussion in 'General Electronics Chat' started by Management, Dec 8, 2011.

  1. Management

    Thread Starter Active Member

    Sep 18, 2007
    306
    0
    I know to get 208 (or 240) you use 3-wire with a Line-to-Line (L1 & L2) connection.

    If I would like to measure the current draw do I need a CT on L1 only or do I need a CT on L2 as well? Shouldn't the current on L1 be the same as the current on L2 but opposite in direction? How much current should be on the third wire? Should it be the sum of both, i.e. zero?

    Thanks.
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    208 is typically two wire. 208/120 is a three wire, with neutral being the third wire.

    In a two wire circuit, current in equals current out. In a three wire circuit, you have to determine what it is that your looking for in regards to the characteristics of your load.
     
  3. Management

    Thread Starter Active Member

    Sep 18, 2007
    306
    0
    Thanks for your response. I am looking for load current. Does a CT around L1 of the 208/120 give me that load current?
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    If it's 2 wire 208, then yes. If it's 3 wire 208/120, then you have more than one load so you'll need two CTs.
     
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