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  1. Unpackage the GFCI coil and components. Unpackage the GFCI coil and components.
    • Unpackage the GFCI coil and components.

  2. Prepare 3 pin connector by sliding shrink wrap tubing onto the white and black wire. Temporarily tape the GFCI coil wires to the connector wires overlapping by 3/4" to 1". Place a large piece of shrink tubing at the end of the CT wires run the orange wire through.
    • Prepare 3 pin connector by sliding shrink wrap tubing onto the white and black wire.

    • Temporarily tape the GFCI coil wires to the connector wires overlapping by 3/4" to 1".

    • Place a large piece of shrink tubing at the end of the CT wires run the orange wire through.

  3. Wrap the orange wire self test wire through the CT 5 times then back to the shrink tubing. Shrink the tubing with a heat gun or very carefully with a lighter to ensure the wires stay in place.
    • Wrap the orange wire self test wire through the CT 5 times then back to the shrink tubing.

    • Shrink the tubing with a heat gun or very carefully with a lighter to ensure the wires stay in place.

  4. Cut the white wire to length leaving one quarter inch overlap and solder to 1 CT wire. Shrink the tubing. Cut the black wire to length leaving one quarter inch overlap and solder to both the orange wire and the other lead from the CT. Shrink the tubing. Shrink a large piece of shrink tubing over the connections to finish your GFCI coil with self test.
    • Cut the white wire to length leaving one quarter inch overlap and solder to 1 CT wire. Shrink the tubing.

    • Cut the black wire to length leaving one quarter inch overlap and solder to both the orange wire and the other lead from the CT. Shrink the tubing.

    • Shrink a large piece of shrink tubing over the connections to finish your GFCI coil with self test.

  5. Test connections with a multimeter set to measure resistance. Orange to Black should measure 0 ohms. White to Black should read 42 to 50 ohms.
    • Test connections with a multimeter set to measure resistance. Orange to Black should measure 0 ohms. White to Black should read 42 to 50 ohms.

    • Connect to OpenEVSE board. Ground (Black wire) should be closest to the board edge.

Finish Line

18 other people completed this guide.

Christopher Howell

Member since: 07/05/2014

6,977 Reputation

20 Guides authored

3 Comments

Will this work with 3 phases?

Johannes - Reply

Title update suggestion: How to Build a GFCI coil with self test AND "Current Measurement Transformer Kit" NOTE: Image of "Built" version of Current Measurement Transformer shows both leads individually insulated with shrink tube whereas "Quick Kit" ships with one piece of shrink tube. The implication of the Quick Kit (imho) is to short the leads, no?

"Built" - http://goo.gl/2YX1L4

"Quick Kit" - http://goo.gl/9MJWIy

Brad - Reply

Thanks Chris: I'll cut the shrink tube in half. I love when I put my foot in my mouth in writing on the Internet. Building a better idiot for nearly 50 years!

Brad -

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