Wiring a Gen 3 Home Charging Unit

[preppucci]

Paul from Massachusetts here and I just got my Generation 3 Home Charging Unit and am wiring this up using a 220v / 40 amp circuit. The wire coming from the circuit is 8-gauge standard electrical wire with 4 braided wires contained within: Line 1 (Black Wire), Line 2 (Red Wire), Neutral (White Wire) and a bare copper ground wire. The installation guide only gives the following diagram and instructions attached.

• They show a Green Wire going to the G Connector.
• They show Black Wire going to Line 1 Connector.
• They show Red Wire going to the Line 2 / N Connector.

They don't mention a Neutral (White) Wire and they state nothing about the bare Grounding Wire? Does the Charging unit not get Grounded?

Should I put the White Wire into the G Connector? They really don't offer any help as I guess they want you to hire one of the Electricians from their site.

Thanks for any help!

 

[JPP]

Historically the HPWC (now WC) did not use a neutral. Do not attach this to the ground at the WC, Just maybe attach a wire nut and then tape it to protect the end of the white wire. BTW you said 8 gauge and a 40A circuit. So dual 40A breaker? Be sure to configure the Wall Connector properly.

 

[preppucci]

Historically the HPWC (now WC) did not use a neutral. Do not attach this to the ground at the WC, Just maybe attach a wire nut and then tape it to protect the end of the white wire. BTW you said 8 gauge and a 40A circuit. So dual 40A breaker? Be sure to configure the Wall Connector properly.

No I have a dual 20A breaker, so 40 amps total. Thanks for the info!

 

[JPP]

No I have a dual 20A breaker, so 40 amps total. Thanks for the info!

You don't add the amps. So you are installing a WC with a 240V 20A system? Your wire gauge will be fine, but your charge rate will be slow. Maybe you can have an electrician (...someone more knowledgable than me) cross check the wire gauge and allowable amperage. Maybe you can bump the breakers up a bit and still be 'street legal'.

 

[msm859]

No I have a dual 20A breaker, so 40 amps total. Thanks for the info!

I would immediately stop what you are doing and hire an electrician. You do not know what you are doing. Also, when you do hire your electrician you should ask how hard it would be to swap for 6 gauge wire. For continuous load you can only charge 80%. So even if you had a 40 amp breaker, you would only be able to charge at 32 amps.

 

[kc10kevin]

Ok...I have to agree that you should probably get an electrician out to help you out. But, if you do insist on continuing, here are a couple of suggestions:

1. Your wire gauge is OK for 40 amp circuit, but would probably go with 6 gauge for future proofing.
Ampacity Charts - Cerrowire
2. Do not go above 32 amps on the Wall Connector for the 40 AMP circuit. (set to 40 amp CB)
3. Get a 2 pole 40 circuit breaker like this one:
Square D Homeline 40 Amp 2-Pole Circuit Breaker-HOM240CP - The Home Depot
4. Do not hook up the white wire (neutral) to the Wall Connector. Just cap it off in the there. Neutral is not used on the Wall Connector.
5. The GND (bare wire) gets connected to the G (or Ground)
6. Red and Black get hooked up to L1 and L2. Really no order for those, but you can follow the color coding.

 

[ry-ballz]

You're going to kill yourself or burn your house down.

 

[I<3URANUS]

You're going to kill yourself or burn your house down.

 

[TORQU3]

No I have a dual 20A breaker, so 40 amps total. Thanks for the info!

That's not how double pole breakers work. You have 20A @ 240V, not 40A. It's an easy mistake but this shows you don't understand the fundamentals.

Please either consult with an electrician or someone a bit more knowledgeable with NEC code before proceeding with your install. At least have you work checked by a professional before using your charging set up for the first time. None of this stuff is particularly hard, but simple mistakes can cause fires.

 

[Rocky_H]

I'm hesitant to even answer questions, given the concerns others have brought up. Please get some electrician help.
The bare wire is the ground wire. It will be hooked up at your main panel and to the ground connection in the wall connector. The white is the neutral, and it's not needed, so you cap it off with a wire nut or just with electrical tape.

And yeah, if it says 20 on it, that is a double pole 20A breaker. You don't double the number.

 

[preppucci]

I'm using a 2 pole 40 amp breaker like the one shown. It says use 8 gauge wire. I understand I'll ony get 32 amps of output from this but according to the manual, that will get 30 miles of charge per hour. I have a friend who is an electrician who is going to bless everything I do so fear not.

 

[TORQU3]

No I have a dual 20A breaker, so 40 amps total. Thanks for the info!

Ok, so this statement was inaccurate right?

The breaker you have pictured is a 2 pole (240v) 40A breaker. It sounds like you have the derating understood for constant loads. Good measure that you are having and electrician friend take a look, well worth the piece of mind.

 

[preppucci]

Yes I was wrong with that statement and thought because it was a 40 amp total, that meant that both duals were 20A. That was incorrect but now I understand that my dual breaker is 40A total.

 

[Jeepxj]

the green wire is ground.

the white wire is not used. cap it with a wire nut/electrical tape

the red and black go into the L1/L2


for the love of god have your friend review everything before power on.

 

[Rocky_H]

well worth the piece of mind.

I see these mixed up a lot, and it's understandable because there are two very similar sounding phrases that are spelled differently that are easy to get confused:

1. "well worth the peace of mind"
Meaning: having peace (calmness) in your mind

2. "I'm going to give him a piece of my mind."
Meaning: I'm angry, and I'm going to tell you what I think about this, whether you like it or not

 

[TORQU3]

I see these mixed up a lot, and it's understandable because there are two very similar sounding phrases that are spelled differently that are easy to get confused:

1. "well worth the peace of mind"
Meaning: having peace (calmness) in your mind

2. "I'm going to give him a piece of my mind."
Meaning: I'm angry, and I'm going to tell you what I think about this, whether you like it or not

You are 100% correct.
I'm happy to know we have the spelling and grammar police active here. It really adds to the conversation.

 

[Big Earl]

Paul from Massachusetts here and I just got my Generation 3 Home Charging Unit and am wiring this up using a 220v / 40 amp circuit. The wire coming from the circuit is 8-gauge standard electrical wire with 4 braided wires contained within: Line 1 (Black Wire), Line 2 (Red Wire), Neutral (White Wire) and a bare copper ground wire. The installation guide only gives the following diagram and instructions attached.

• They show a Green Wire going to the G Connector.
• They show Black Wire going to Line 1 Connector.
• They show Red Wire going to the Line 2 / N Connector.

They don't mention a Neutral (White) Wire and they state nothing about the bare Grounding Wire? Does the Charging unit not get Grounded?

Should I put the White Wire into the G Connector? They really don't offer any help as I guess they want you to hire one of the Electricians from their site.

Thanks for any help!


View attachment 511853

Neutral does not get used in a 240 volt split-phase arrangement. Cap it.

Your bare copper wire is the ground and gets connected to G (where the green wire is on the diagram).

Please have someone with electrical skills review your work before turning it on.

 

[msm859]

I'm using a 2 pole 40 amp breaker like the one shown. It says use 8 gauge wire. I understand I'll ony get 32 amps of output from this but according to the manual, that will get 30 miles of charge per hour. I have a friend who is an electrician who is going to bless everything I do so fear not.

View attachment 512192

What car are we talking about? I have a 50 amp breaker charging at 40 amps. With the X it gives me @29 miles per hour - less when I turn climate on.

 

[Rocky_H]

What car are we talking about? I have a 50 amp breaker charging at 40 amps. With the X it gives me @29 miles per hour - less when I turn climate on.

You have the original gen1 mobile connector that can do 40A. The newer gen2 can only supply 32A. And this would probably be a Model 3, which being more efficient, can get more miles per hour from less charging power. So at 32A, I think about 30 mph is about right for that one.

 

[preppucci]

I have the new Gen 3 Charger and my Tesla is the Model 3, standard range. According to the manual for the charger, the best I can even get with this charger on the model 3 is 32 Miles per hour of charge, so the 40 Amp circuit is the max I can do.