5 of 20 - Installing the External Meter and CTs (Current Transformers)

 This external meter is designed to measure energy consumption and exportation of the home being monitored.


Installing the Meter

  1. The meter should should be installed in one of the following places: inside of a NEMA rated box near the service panel or in the service panel itself
    1. Inside of the service panel (if there is room) - this is the ideal place to install it
    2. Inside of a NEMA rated box installed next to the service panel - second best option
    3. Inside of the inverter wire box as a last resort
      1. Multiple wires will need to be ran from the service panel to the wire box in this case
        1. Two sets of wires (four in total) of #14-16 AWG wire for the CTs
        2. Three wires for the reference breaker (#12-14 AWG)
          1. L1
          2. L2
          3. Neutral
  2. Secure the 35mm DIN rail and then snap the meter onto the rail

Installing the Current Transformers (CTs)

  1. Two CTs should have been sent along with the meter 
  2. Turn off AC power before clamping the CTs around the conductor cables
    1. If this is not possible, be extra careful when installing the CTs
  3. Install the CTs around the conductor cables supplying the service panel (see photo above)
    1. Split-core CTs can be opened and closed - start by opening both CTs
    2. The label on the CT needs to face towards the utility and away from the service panel (VERY IMPORTANT)
    3. Clamp one CT around the L1 wire - it should snap closed   
    4. Clamp the second CT around the L2 wire - it should also snap closed
    5. Note: some service panels are supplied by bars instead of cables
      1. If this is the case, then a different type of CT will be required
  4. Each current transformer has two signal wires coming off of it - these need to land in the meter's top right corner (detailed instructions below)
    1. There is a positive (+) and negative (-) wire for each CT
    2. Be sure to land the wires correctly or consumption will not be measured accurately 
    3. L1 CT gets the positive and negative wires from the CT around the L1 wire
    4. L2 CT gets the positive and negative wires from the CT around the L2 wire


Wiring the Meter:

  1. Verify that power is OFF before making connections. 
  2. Install a double-pull 15A breaker (reference breaker) in the service panel where the meter is installed
    1. If there is not enough room for a breaker then use quad breakers to make space
    2. Double-landing is not recommended, especially in the inverter's AC input terminals
  3. Connect the AC side wires (meter input) using the 5-pin terminal block: 
    1. Loosen the appropriate screws on the 5-pin terminal block. 
    2. Connect each AC wire to the appropriate screw terminal and verify that the lines match the symbols printed on the meter front label. 
      1. L1 wire to L1 terminal of the 15A breaker
      2. L2 wire to the L2 terminal of the 15A breaker
      3. Neutral wire to the neutral bar in the service panel
      4. Ground wire to the ground bar in the service panel
    3. Tighten the screws making sure the wires are fully inserted and cannot be pulled out easily. 
    4. Insert the 5-pin terminal block into the socket on the meter making sure it is fully seated in the meter. 
  4. The 15A reference breaker can be turned on - the three lights on the meter should turn on if it is wired properly
  5. Connect the RS485 twisted pair cable to the 4-pin terminal block in the top left corner of the meter: 
    1. Connect two wires to the A+ and B- terminals, and connect the shield to the G terminal. 
    2. Insert the 4-pin terminal block into the socket on the meter making sure it is fully seated in the meter 
  6. Return the terminal block end-stops to the sides of the meter.


Connecting to the Inverter

  1. A technician screwdriver will be needed for this step as the terminals are spring-clamp
  2. First, an RS485 communication cable will need to be ran between the meter and the inverter
  3. Land the A wire from the meter in terminal 10 of the communication port inside of the inverter
    1. This is the terminal furthest to the right (MTR485A)
  4. Land the B wire from the meter in terminal 9 of the communication port inside of the inverter
    1. This is the terminal just to the left of the furthest right terminal (MTR485B)
  5. Land the ground wire from the meter in the ground bar of the service panel or inverter
  6. On the screen perform the following steps:
    1. Press Enter
    2. Scroll to Advanced Settings and press Enter
    3. Press Down, Down, Up, Enter (0010) for the password
    4. Scroll down to Storage Energy Set and press Enter
    5. When "Meter Select" is highlighted press Enter
    6. Select "1Ph Meter" and press Enter
  7. Return to the main menu using the ESC button 
  8. Enter the Information menu and look for a section titled "Meter Info - External"
    1. This should display grid voltages and house power importation/exportation values
    2. If no information is displayed then the meter communication wires need to be checked at both ends
    3. If communication wires are ok then the meter itself is having issues - check voltages at the input terminals
    4. If AC voltages are being displayed but no current is then check the CTs and CT wires 




M
Michael is the author of this solution article.

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