Wall charger wiring

edited November 2018 in General
I am on the last steps of attaching a wall charger, and I'm having trouble with the screws on the green L1 and L2 terminal block. They tighten just fine, but don't grip onto the wires from the top mount and the wires can slide right out.

I'm shoving the wires in so far that you can only barely see the yellow part of the wires and they still don't stay when the screws are tightened.

Any ideas on what I'm doing wrong?


  • edited November 2018
    I think you're talking about the wires with square terminals on the ends. With those, I really had to back the screws out far, then shove the wire ends in as far as possible. It took me a couple times to get it right.
  • edited November 2018
    I am indeed talking about the square terminal wires. As I mentioned, I shoved them all the way in where the yellow coating at the end was not visible, but it still wasn't enough.
  • edited November 2018
    The back of the saddle moves away from you when you loosen the screw; tightening the screw pulls the back of the saddle towards you and clenches the wire. When the saddle is loose, you can easily miss—especially since the wire is thick and hard to bend.

    If you still can’t get it by feel, get a cheap dental mirror from the drug store and use it to watch the saddle move while you turn the screw—you’ll see see where the wire goes for sure. Good luck!
  • edited November 2018
    That is some primo advice. Thank you!
  • bpbp
    edited November 2018
    Tesla provides specifications on the amount of torque to be applied for the posts. When Tesla installed our Gen 2 HPWC, I believe they not only took measurements, they also took photographs of the measurements to document they had made the connections correctly.

    Especially if you're going to run high amps through the HPWC, improperly connecting the HPWC to the power cables could pose a safety/fire hazard.

    When our first HPWC was installed, the first breaker it was connected to melted, because it had not been properly seated by the electrician during installation...
  • edited December 2018
    @bp: indeed, it is important to seat and torque the connections properly—sounds like your electrician was extremely careless at the breaker side, I wouldn’t hire that guy again!

    The Tesla Wall Connector monitors the temperature at the terminal block, and will dial back the charging current if it’s too hot—so not much risk on the wall connector side. Of course there is no such safety on the breaker side, but those connections are made while holding the breaker in your hand, outside the panel where it’s easy to see. It’s surprising and discouraging that an /electrician/ messed this up for you.
  • edited March 2019
    My terminal block melted so it doesn't measure temperature well!
  • edited March 2019
    @mattjurek, unlikely, since the terminal block is designed to carry more current than necessary. More likely, the wire was under specification for the amperage, so the wire melted.
  • edited November -1
    Temperature is measured in the Tesla side of the connector - not the wall connection. I think Dan hit on the issue. Two other reasons - improper mix of aluminum wire and incompatible receptacle, or the connections at the receptacle were not properly torqued. Might be time for a different electrician to fix the problem.
  • edited November 2019
    This was exactly what I needed. Thanks! I am also having trouble with getting the terminal block to grip the wire. I am using 4 gauge wire without any crimped on square ends in a low profile mount with rear entry wiring. Has anyone successfully done this or do I need to find ferrules for the wire as per page 19 of the wall connector instruction manual? Has anyone found a source for the specific ferrules that will fit the terminal block?
  • edited November 2019
    So I was able to connect it without the ferrules. Tips for others: bend the wire so that when you are pushing it into the connection block it is going in straight. Most importantly, when you loosen the screw before inserting the wire, you need to push on the loosened screw to move the screw assembly into the connection block; this will line up the passageway for the wire to slip in. This is why I was having trouble and using a small mirror showed me the solution.
  • edited November 2019
    @drbrockley - Are you using Alumimum wires? If so, make sure the terminal block is rated for aluminum wire, and you should use some no-ox on the wires before clamping down. Lastly, it's fairly important that the screws be torqued to the recommendations. If using copper, then none of this applies.
  • edited November 2019
    Thanks for the feedback, TeslaTap. I did use copper 4 gauge two conductors plus ground and tightened the screws as much as I could without stripping the head.
  • edited November 2019
    Great! I always recommend copper, as it is just easier to get right. Aluminum is ok if everything is done right, but it requires more steps that are often unknown or ignored.
  • edited March 2020
    I was having this exact problem and it was very frustrating to be so close to finishing the installation and I just couldn't get the wires to be engaged by the terminal strip.

    Dan Foster your description was perfect to better understand how the terminal strip mechanism works since it's recessed and not very visible. And thanks for suggesting a dental mirror. I'd been using a small cosmetic mirror and just couldn't see much. You reminded me that I also had put aside a dental mirror just for situations like this.

    With Dan's insights I was able to get the cables installed securely in my very next try. THANKS!
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