Which home Wall Connector

[Ric Shaner]

Hello,

I am looking to have a wall connector installed in my garage. There are several options available both the Tesla brand and others. I am dead set on buying a Tesla M3, although not sure it it will be Standard or Long range. What I know about electricity, amps, volts and the like can fit on the head of a pin. I would like advice on whether or not to by the Tesla Wall Connector or another brand, if another brand which one. My Tesla will be mostly a daily driver.

Thank you,

Ric

 

[RayK]

Sorry to get OT a bit but questions were asked which need to be answered....

All of the above, plus a bad design of the outlet in question.

Charging an EV is perhaps the biggest electrical load you could force on your home's power circuits. An A/C unit tends to cycle on and off during the day (not ours, but that's another story). Similar thing goes for an electric oven, which might be on for 5 or 6 hours cooking a turkey. But that also does not draw power constantly; it cycles on and off to maintain a constant temperature. A Tesla being charged by a mobile connector can consume 32A of 240V for HOURS ON END.

Heat, and any resulting fire which might occur, is typically a function of a lot of power going through a "bad" electrical connection. Any resistance to the amount of current being drawn will cause a rise in temperature. A cheap, residential-type outlet (i.e., common Leviton brand) skimps on the materials for the blades inside the socket, either by composition or amount. This can result in a higher electrical resistance to the transfer of power. That leads to overheating and in some cases, a melting outlet and a possible fire.

There can also be a bad connection at the back of the socket, where the wire(s) are connected. Failure to tighten the screws holding the wire(s) to the correct torque specification can mean that over time, the connection loosens and again, a higher resistance. In fact, it's recommended to re-tighten the screws after a period of time, just in case they start to get loose.

One to the worst things one can do is rely on the push-in terminals of the socket (if so equipped) to connect the wires. Those are commonly referred as "stab-in" holes, which makes it easy to connect things up (rather than spend a small amount of time to grab a screwdriver and twist away) but is not the way to do things if pushing a large amount of power through the socket.

edit: Then you have the possibility of somebody using a mobile connector on a 14-50 outlet and unplugging it often. That can lead to a weakened connection over time and a higher chance of "A Really Bad Thing Happening".

 

[ucmndd]

I think I was looking at it as more of preventing so much power to go through that might cause a fire like this.

Ground fault detection isn’t meant to do that.

I'm not an electrician so I'm just asking. What causes fires like this? A bad electrical install? Too much power going through the plug? Constant charging?

Poor contact between conductive surfaces causes resistance or even electrical arcing depending on the circumstances. Both of those create resistance, which creates heat, which can get hot enough to melt things under high current for long durations.

Common causes for 14-50 outlets include:

• Bad installation - poorly torqued lugs, pinched insulation in the lugs, etc
• Outlet fatigue - most 14-50 receptacles are not meant for regular plugging and unplugging. If you do this a lot the receptacle can loosen, oxidize, or otherwise create a poor contact that heats up and melts
• Sub-par contractor grade outlets from big box stores that aren’t meant for continuous current like this

 

[Cosmacelf]

Man, I love these threads. OP comes in wanting to do things the right way, admitting they have limited electrical knowledge, and wanting some general high-level advice.

First few posts answer the question actually asked, do so succinctly, and with an amount of technical jargon appropriate and sensitive to OP’s level of understanding.

Then someone comes in telling us what their setup is, using undefined acronyms and immediately talking about volts and amps.

Then a crazy long technical jargon-laced post telling OP that hey, if you don’t want to do things the right way, there’s lots of great ways to do things more crappily.

Then someone else comes in with yet something else to consider, another suboptimal and nearly as expensive solution to accomplish the same thing.

Then we post pictures of electrical fires.

Y’all are really selling the EV experience…

THANK YOU! I was going to say the same thing but couldn't figure out how to say it properly. You nailed my sentiments!

 

[ATPMSD]

You should definately install a 60a circuit if your circuit breaker panel will support it. Upgrading later is expensive since you would have to rerun the wire.

With that said if you go with the 60a option, do NOT allow the electrician to use #6 Romex wire! A 60a circuit requires wire rated for a full 60a, #6 Romex is rated for only 55a. If the electrican wants to used #6 Romex, find a different electrician.

 

[AttoPro]

Also, there are two wall connectors. The "universal" one has a plug for non-Tesla vehicles... don't get that one.

$450.

Curious, aside from costing a bit more and NACS becoming a future standard here in US, are there other reason not to get the universal kind that has J1772?

 

[father_of_6]

Curious, aside from costing a bit more and NACS becoming a future standard here in US, are there other reason not to get the universal kind that has J1772?

Just my opinion. I wouldn't pay more for it and then have to have an additional unnecessary adapter floating around. Looks like it sits inside the base, but it also seems like the base might be larger to accommodate.

 

[Eric33432]

My 2¢:

Definitely the Tesla Wall Connector.

Any 240 volt charging will top off your car overnight, but there may be a few times when you want to charge your M3 more quickly than overnight, so install as large a circuit as your electrical service will economically allow (up to 60 amps).

Example, you come home at 15% from a road trip, and you plan to go out to dinner an hour or two later. At that time, having the larger circuit will be appreciated.

Another example, you are on time of use billing with a small time window for the least expensive rate. You want to charge the car during that time period.

M3 RWD maxes at 40 amp circuit (32 amp charging) but this circuit will last for 50 years or more. Who knows what car you will have in the future.

 

[DuncanM]

My 2¢:

Definitely the Tesla Wall Connector.

Any 240 volt charging will top off your car overnight, but there may be a few times when you want to charge your M3 more quickly than overnight, so install as large a circuit as your electrical service will economically allow (up to 60 amps).

Example, you come home at 15% from a road trip, and you plan to go out to dinner an hour or two later. At that time, having the larger circuit will be appreciated.

Another example, you are on time of use billing with a small time window for the least expensive rate. You want to charge the car during that time period.

M3 RWD maxes at 40 amp circuit (32 amp charging) but this circuit will last for 50 years or more. Who knows what car you will have in the future.

A 60amp/240v circuit is likely to be the largest, single circuit, breaker in the OP's electrical panel. A typical home in North America has a 200amp/240v main breaker, so it's a bit more complicated than just installing the highest current possible breaker/EVSE to feed an EV. The OP admits to knowing little about volts and amps so he probably should state the various loads on his panel and it's main breaker amperage. He should have a load evaluation done by an electrician, as he could, potentially, be overloading his panel depending on the other high amperage/240v loads that it's feeding.

Our winter home in SE AZ has the following (IIRC) 240V breakers and loads:
40Amp/heat pump
50A/stove
40A/dryer
40A/HW Tank
20A/EVSE
190A
You can see that in our home a 60amp/240V EVSE would be pushing the 240v nominal loads, alone, to 230A. Of course we don't normally have all these loads maxed out and the breakers are ~20% oversized, but with 120v loads added in, we could potentially trip the main breaker if the EVSE was drawing 48A.

 

[jjrandorin]

Man, I love these threads. OP comes in wanting to do things the right way, admitting they have limited electrical knowledge, and wanting some general high-level advice.

First few posts answer the question actually asked, do so succinctly, and with an amount of technical jargon appropriate and sensitive to OP’s level of understanding.

Then someone comes in telling us what their setup is, using undefined acronyms and immediately talking about volts and amps.

Then a crazy long technical jargon-laced post telling OP that hey, if you don’t want to do things the right way, there’s lots of great ways to do things more crappily.

Then someone else comes in with yet something else to consider, another suboptimal and nearly as expensive solution to accomplish the same thing.

Then we post pictures of electrical fires.

Y’all are really selling the EV experience…

TBH, most of the time, you are like that voice of all the stuff I "want" to say, but cant, for various reasons.

(this is absolutely one of those times, lol).

 

[BigMskiman]

For reference, I have a TWC on a 50 amp, 240V circuit so can charge at up to 40 amps continuous. I set my MYLR to charge at 30 amps which gives me 10% an hour so would be even faster on a M3.

This is also my setup & use exactly. 30amps and programed to charge off peak hrs, you are golden.......with margin

 

[kpanda17]

The Tesla wall connector is the highest quality and best value option available.

All North American car companies are switching to the Tesla plug standard (NACS) in the next couple years, so buy the right connector and get ahead of the curve.

Definitely Tesla connectors, number two me by JD Power ratings.
The Wall Connector is gen 3 and has NACS, house to vehicle charging.
The Universal Wall Connector is gen 4 and has both NACS and J1772 but as an advantage and tire proofing, house to vehicle and vehicle to house (V2G) charging.
Therefore you want the Tesla Universal Wall Connector.

 

[kpanda17]

SAFARI CRASHED, CORRECTED

Definitely Tesla connectors, number one by JD Power ratings.
The Wall Connector is gen 3 and has NACS, house to vehicle charging.
The Universal Wall Connector is gen 4 and has both NACS and J1772, using their Magic Dock, but has the advantage and future proofing with both house to vehicle and vehicle to house (V2G) charging.
V2G will become more available over time on vehicles.
Therefore you want the Tesla Universal Wall Connector.

 

[ATPMSD]

Curious, aside from costing a bit more and NACS becoming a future standard here in US, are there other reason not to get the universal kind that has J1772?

The only reason I would consider the “universal” is if I already owned an EV with a J1772, or was planning to buy an EV with a J1772. Otherwise, it is just a waste of money - to me.

 

[Sellout]

You should definately install a 60a circuit if your circuit breaker panel will support it. Upgrading later is expensive since you would have to rerun the wire.

With that said if you go with the 60a option, do NOT allow the electrician to use #6 Romex wire! A 60a circuit requires wire rated for a full 60a, #6 Romex is rated for only 55a. If the electrican wants to used #6 Romex, find a different electrician.

The cable running from the Tesla wall charger to the car gets warmer than my #6 Romex cable while charging the car at 48 amps. (60A circuit) It’s also pretty significantly thinner than that #6 romex cable.

Can someone explain how 240V 48A running through wire rated for 600V and 55A is too much? I’m not an electrician but I’ve got an expert-level refrigeration tech’s understanding of electrical loads… (which probably means I’m slightly less likely to kill someone than your average apprentice electrician lol)

Edit: typo

 

[ucmndd]

Can someone explain how 240V 48A running through wire rated for 600V and 55A is too much?

NEC allows 80% of rated conductor ampacity for “continuous loads” like EVSEs.

80% of 55 amps is 44, not 48.

 

[ATPMSD]

@Sellout

As @ucmndd noted, you cannot pull 48a in wire rated for 55a, it is a code violation. If this is your setup you need to change the configuration in the wall connector to a 50a circuit and you should also replace the 60a breaker with a 50a. Using a 60a breaker with 55a wire is also a code violation. Yes, there is something called a “round-up” but it cannot be used here.

 

[emtron1309]

Tesla Wall Connector hands down.

Tesla Wall Connector hands down.

I recently installed the Juice Box wall connector hard wired into my home's circut breaker box. Installation cost with a certified electrician was $300 USD. With the Puget Sound Energy Flex Event discount the wall charger cost me $299 USD. During Brown Outs the PSE Flex Event program will pay me .50 cents per KiloWatt Hour not to charge. The Juice Box is programmed to keep track of all of this. Plus, PSE rewarded me $100 for signing up.

 

[Sellout]

Guess I was looking for more of an understanding of the actual heat generation in the conductor than regurgitated code info, but thanks anyway guys.
Code doesn’t really matter to me, I’m not trying to sell my house with the wall-connector installed. I do know that it matters how long the conductor is when you’re talking about the current-carrying capacity of the wire, but there’s no mention of how long or short a #6 copper wire can be in that rating on the spool.

My six foot long #6 wire really does stay room temp with 48 amps flowing through it while the ten foot cable going to the car from the wall connector gets slightly warm.

But yeah, I’ll set it down to 50amp circuit and pick up a 50A breaker today. I don’t actually need 44 miles/hr, nor do I need my homeowners insurance policy being canceled because I posted about this online lol

 

[ucmndd]

Guess I was looking for more of an understanding of the actual heat generation in the conductor than regurgitated code info, but thanks anyway guys.

Practically speaking you’ll never have an issue with your setup. NM-B (Romex) is de-rated to the 55c temperature limit because under extreme conditions - long runs through attics, super high-temp environments, etc - the insulation retains more heat than conduit and doesn’t dissipate it as effectively.

Is a six foot run in San Diego ever gonna be in conditions like that to cause problems? No. Is it to code? No.

 

[RayK]

Heat generation is a function of resistance in the wire; more resistance = more heat. Shorter length of wire = less resistance. Your 6' of #6 Romex, while not conforming 100% to code, will not heat up compared to 100' of it.