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How do these lugs work on the latest Wallbox EVSE?

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holeydonut

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Jun 27, 2020
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East Bay NorCal
Spamming the TMC brain trust, since I have no clue who else to spam. Some Mercedes EQ vehicles now come with a free Wallbox EVSE. Unfortunately, it doesn't have normal screw/hex/torx lugs for the conductors (L1, L2, GND). Instead, it has what you see in the images below (potato chip for scale). Does anyone recognize how you're supposed to get your copper conductor properly inserted?

No joke, the Wallbox installation manual and the MB-USA installation guide just tell you to get a qualified electrician to do the install. Contacting Wallbox support just gets someone who sends a PDF for the previous-gen Wallbox instructions that has normal lug screws (philips).

My neighbor is a former electrician, and he's said he's never seen this. There are no instructions on how to use these lugs. There's also no other min-busbar or other bracket in the box. No extra lug hardware or anything in the package.

Our hypothesis is that Mercedes actually wants you to go through specific installers who actually have the hardware necessary to affix conductors to these lugs. Kind of like getting a lock for free, but no key. Or maybe there are some bullet termination ends we're supposed to crimp on and jam in there? Very weird.

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Edit; tagging @wwhitney because he knows everything...
 
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It looks like the lugs seems to be the quick install type, just insert the wire in the hole.
And there is a smaller hole above to release the wire.


You could contact Tom Moloughney, he might have one installed in his garage....

View attachment 1037820

Yeah, I thought about it being friction based, and I can sneak in #6 into that big hole. But it just feels lose/janky no matter what I do. I don't know why they didn't use a screw-down lug. The Tesla Gen 3 EVSE is just so damn good haha. This Wallbox thing just isn't worth the hassle.

No knock against Tom - he's been super helpful in the EVSE space. But he's now sponsored by QMerit (they are the ones that administrate this MB-USA Wallbox promo). Tom has been advising against DIY since he was seeing so many homeowners sending in burned out or screwed up installs. He recommends EVSE's, but advises people use Qmerit to source electricians to do the install.

He doesn't even think an average electrician should be the one brought out. He thinks the QMerit-certified folks will be the "right" ones to install a new EVSE. Here's his video about topic.

 
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How is the wire going into the ground block right above the open ground block you pointed to? It looks like there is a piece of reflective metal (maybe it's reflective plastic) and then at least a single similar connector on the other side of that support bracket.
 
How is the wire going into the ground block right above the open ground block you pointed to? It looks like there is a piece of reflective metal (maybe it's reflective plastic) and then at least a single similar connector on the other side of that support bracket.

Yeah that green ground wire was already attached. It seems they have a connector for that wire. But there’s no way to get my own copper conductor to terminate in that recess.

Given both Tom and Sandy both have identified that improper torquing of the connectors is to blame for a lot of melted EVSE hardware, I can’t believe Wallbox would ship this thing in this state. You know someone’s going to just muscle in #8 into that port and call it a day. But that wouldn’t be a proper install.

I get it, they want to push business to Qmerit, but this is a crummy way to go about it.
 
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These types of connectors are pretty common. I see them a lot in solar inverters.

Usually you have to push in a small flathead screwdriver in the smaller top slot and it will let you put a bigger wire in the bottom hole.


Any chance you have a product/model inverter that you believe have these?

At first, these things in the Mercedes Wallbox reminded me of the SMA inverter terminal block. Unfortunately jamming in the big conductor, and then jamming in a screwdriver to the small slot didn't actually lock down the wire where it felt secure.

I mean, if they put a allen or philips screw-down in there it'd be like 100% awesome and easy. Reinventing the wheel here just seems... weird.


From:

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Any chance you have a product/model inverter that you believe have these?

At first, these things in the Mercedes Wallbox reminded me of the SMA inverter terminal block. Unfortunately jamming in the big conductor, and then jamming in a screwdriver to the small slot didn't actually lock down the wire where it felt secure.

I mean, if they put a allen or philips screw-down in there it'd be like 100% awesome and easy. Reinventing the wheel here just seems... weird.


From:

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I think you're supposed to put the wire in the hole, jam the small screwdriver in, then push the wire further in the hole, before removing the screwdriver which should lock down on the wire. I'm think of the terminals in the SolarEdge inverters.
 
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I think you're supposed to put the wire in the hole, jam the small screwdriver in, then push the wire further in the hole, before removing the screwdriver which should lock down on the wire. I'm think of the terminals in the SolarEdge inverters.


Got it thanks! I looked it up and indeed the DC side has similar looking terminal blocks. What's weird is the AC side still has screw-down lugs lol.

If it's good enough for a solar inverter then it's good enough for this Wallbox I guess. Now I know what to tell the buyer when they ask me how they're supposed to land the conductors on these lugs haha. I'm sure not going to install this Wallbox in my garage.

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And their UL or other recognized testing lab listing for the device should be at risk if they do not supply instructions adequate for any licensed electrician to safely install the device.

You might try telling them so, and offering to let UL know of the problem as well.
 
Hello Everyone,
I just got my Mercedes wallbox charger and I am trying to install it. But ran into the following problem.

I have installed a 240 volt, 50 amp , 4 prong outlet in the garage and now I have to connect the Mercedes wallbox to it. And instead of hard wring I bought a cable just like the one in the picture.

The problem is Mercedes has 3 ports to connect wires, but the 4-prong outlet has 4 wires.
I believe the red and black wires as L1 and L2 have the colors matching, but the problem is if I connect the white wire to the green inlet in the Mercedes wallbox to have full power, there is not grounding (ground wire has not connection or place to connect)..

I see that there is an orange wire for the ground, But I cannot find any place to connect the green wire for the ground from the 4 prong wire and plug that I purchased to the Mercedes wallbox.

Anybody knows where should I connect the ground (green) wire to the Wallbox charger?

I really appreciate your help
 

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Hello Everyone,
I just got my Mercedes wallbox charger and I am trying to install it. But ran into the following problem.

I have installed a 240 volt, 50 amp , 4 prong outlet in the garage and now I have to connect the Mercedes wallbox to it. And instead of hard wring I bought a cable just like the one in the picture.

The problem is Mercedes has 3 ports to connect wires, but the 4-prong outlet has 4 wires.
I believe the red and black wires as L1 and L2 have the colors matching, but the problem is if I connect the white wire to the green inlet in the Mercedes wallbox to have full power, there is not grounding (ground wire has not connection or place to connect)..

I see that there is an orange wire for the ground, But I cannot find any place to connect the green wire for the ground from the 4 prong wire and plug that I purchased to the Mercedes wallbox.

Anybody knows where should I connect the ground (green) wire to the Wallbox charger?

I really appreciate your help
And this is wiring diagram.
I forgot to post this last picture from the Mercedes Wallbox manual

Anybody knows where should I connect the ground (green) wire to the Wallbox charger?

I really appreciate your help
 

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I have installed a 240 volt, 50 amp , 4 prong outlet in the garage and now I have to connect the Mercedes wallbox to it. And instead of hard wring I bought a cable just like the one in the picture.
That is intended to be a hard wired device instead of a cord-and-plug type, so you're already violating the manufacturer's installation instructions, and thereby violating electric code as well.

The problem is Mercedes has 3 ports to connect wires, but the 4-prong outlet has 4 wires.
That "problem" is because it's not meant to be connected to a 14-XX outlet.

I believe the red and black wires as L1 and L2 have the colors matching
Yes, those are the Hot1 and Hot2.

but the problem is if I connect the white wire to the green inlet in the Mercedes wallbox to have full power, there is not grounding (ground wire has not connection or place to connect)..
That's a wrong connection. The white wire is for neutral in the 14-50 circuit. The wall connector does not use neutral at all. That white wire should just be capped off and not connected.

I see that there is an orange wire for the ground, But I cannot find any place to connect the green wire for the ground from the 4 prong wire and plug that I purchased to the Mercedes wallbox.

Anybody knows where should I connect the ground (green) wire to the Wallbox charger?
The green wire from that 14-50 cord is the ground. It should go to the ground connection in your wall connector.