Home Installation Of Level 2 EVSE For An Electric Car

OCT 27 2014 BY STAFF 40

Bosch EVSE

Bosch EVSE

Ironically, it was easier to decide to purchase an all electric Solar Orange BMW i3 than it was to decide on which Level 2 Charger to buy. BMW sells a very nice looking charger, the BMW i Charging Station, for $1,080 and as with all other chargers installation is extra.

However, it was the BMW Wallbox Pro which BMWBLOG reported on from the BMW i8 launch back in April that I really, really wanted.

I was super excited about this particular one because we have a newly installed 12kW solar system in our house and I relished the idea of being able to program where the electricity was to come from to charge our Solar Orange i3. Sadly, this fantastic device is still not available and now word on when it will be.

So Many Options In The World Of EV Chargers

When looking at an electric car charger, it helps to know a bit of the lingo. EV nuts are very particular about their verbiage. Though commonly called a Level 2 Charger, the proper term is Electric Vehicle Service Equipment (EVSE) because the actual AC to DC conversion occurs on board the EV itself. It will be hard to break the public of the habit of calling them Car Chargers, as that’s what manufacturers call them.

*Editor’s Note: This post appears on BMWBLOG.  Check it out here.

Hitting on the basics of electricity supplies, in the United States a 110V is a common household plug, and 240V is what is used for household electric ovens, dryers and air conditioning units. A 240V outlet can charge an electric vehicle twice as fast as the 110V. A Level 1 Charger, which uses a household 110V current, is good when you are in a pinch – BMW even calls it an “occasional charger” so you get the hint that you need a Level 2 Charger.

When it gets to where electricity meets the EV, the SAE J1772 Charging plug is standard for all electric vehicles except the Tesla cars which have a proprietary charging plug. Thanks Elon!

Bosch EVSE

Bosch EVSE

Why Do I Need A Level 2 Charger?

Level 2 Units can charge up to 7.2 kW and pull 30 amps, and need to be installed on a 40 Amp circuit with 8 gauge wire. There are DC chargers too but they are 480 volts and cost around $8,000. Thankfully the Rapid DC chargers are becoming more common at commercial charging sites on the East and West coast. The DC Charger, CHAdeMO aka a Level 3 Charger, can pump a stunning 62.5 kW of direct current right into the battery.

On the BMW i3, it does require an optional $700 factory connector. I am told that this is factory installed only, if you don’t get it at manufacturing of your vehicle, you cannot retrofit it.

There are more Level 2 Chargers available than I would have thought. See our table for the most popular ones out there.

A Few Of The Available EVSE Units

A Few Of The Available EVSE Units

BMW i Charging station is 30-40% more expensive than all the other units, so it was immediately at a disadvantage. As Bosch is the manufacturer of BMW’s i Charging Station, I was immediately drawn to it. Bosch’s charger is a much smaller unit with a center holster that docs the J177A Charging Plug. The unit is available with a 18 ft or a 25 ft long cord.

The Siemens unit has a very German efficient layout while the GE one looks just like the one that Porsche uses for their plug-in hybrid cars. There’s also a very robust unit from Clipper Creek, the HSC-40 but I didn’t like the lack of contained plug doc and it’s rather unattractive compared to the other units.

Bosch EVSE

Bosch EVSE

The Bosch charger has a LED indicator flashing blinking green when you are charging. It also has an unit On/Off switch on the side to keep it from using any power when not in use. Bosch offers a 3 year warranty when installed by Bosch or 1 year if you do it with your own electrician.

One of the main reasons I went with the Bosch was itself contained connector dock which looks better and protects it from accidental drops. The cord also neatly stows wrapped around the unit. The size of the charger is on the small side: 16” by 14” x 5”. The BMW charging unit, on the other hand, is the size of a pay phone, if you remember what those look like.

Ultimately we elected to go with the Bosch 25’ as everything I’ve read said get the longest cord you can.

Level 2 Chargers require a dedicated 40amp 240V circuit. Here is where costs for installation can be all over the map. If you don’t have enough capacity in your house, you need to upgrade the whole electric service to the house. Ka-ching!

Is There Room To Add My Level 2 EVSE?

Is There Room To Add My Level 2 EVSE?

In my opinion, you need at least 200amp service to your house to be able to add a 40amp circuit. Some older houses only have 100amp service. The second biggest cost determinate is how far you have to run the wires from the breaker box. In my case, it was about 30 feet through two finished walls and a crawl space above the garage. If you have an unfinished wall where your breaker box is, and you’re just gonna pop-out the side and place the charger right there, it’ll cost much less.

Take home lesson is: not all 240V circuits are the same. I had this grandiose plan of installing the whole thing myself, until I learned I needed 8 Gauge wire. I had planned on just using the wire from my 2-Post lift in the garage by redirecting it but this is only on a 20amp circuit. Seriously, unless you really know what you are doing, call a professional. I’ve done 110 circuits myself in the past but still called in a professional just to make sure I didn’t kill a brand new car.

NEMA 14-50

Good grief, the EV terms just don’t end.

NEMA 14-50 was not a term I was familiar before this electric journey I’ve undertaken. Anyway, it’s the way I decided to get power to my Level 2 Charging unit. The benefits of connecting a Level 2 charger this way are multiple. The biggest of which is you can simply unplug the device if you move versus call an electrician.

A bonus is when a buddy with a Tesla Model S shows up in your drive way, you can unplug your charger and have the Tesla plug directly into the NEMA 14-50. Same goes for the in-laws RV or even a welder. If you hardwire your Level 2 Charger, you loose all that flexibility. Once my electrician had the 14-50 receptacle all wired up, I sent him on his way with a check for $318.60 and I finished the rest of the install.

In order to connect our Bosch Level 2 charger, I had to add a NEMA Plug which was not included. It cost $23 from Lowes, and can handle 50 amps. A “range” plug they call it.

How hard could it be to install? Well, it sucks!

There’s no color coded labels to tell you where to put your white/red/black and green wires in the back panel of the Bosch unit. In fact, there are only three spots for wires and I have four hanging off the plug. Hmmm. I pull out instruction manual and it says L1, L2 and N. Hmmm again. Maybe I shouldn’t have sent the electrician away.

Hmmm...Which Wires Goes Where?

Hmmm…Which Wires Goes Where?

No fear. I’ll call Bosch.

I get a someone on the phone from tech support and, I am not making this up, they say “call an electrician.” I ask, “I am on the phone with tech support for an electric car charger and you cannot tell me how to deliver electricity to it?” They answer: call an electrician. Nuts. I love the Untied States of Attorneys.

I hung up and saved my choice explicatives for the crickets in the garage. No fear, because I tapped the BMW i3 Facebook Group and rapidly got the answer I wanted. L1 and L2 are red/black, and N was green. I am just telling you what I did and electric codes could be different in your area. I had to drill out the bottom plastic section of the Bosch unit so the wires could come straight out of the bottom of the unit. It required a fancy $5 1” drill bit from my hardware store.

Hanging the unit was simple. A level two number 8 wood screws went into a stud to secure the metal bracket to the wall and then three torx T30 screws holding the unit to the metal bracket. Then plug the unit into the NEMA 14-50 plug. Since our BMW i3 wasn’t yet delivered to our dealer, they were kind enough to let me test drive one and make sure the install went fine. Read our experience of BMW’s 3 day extended test drive here.

There are lots of choices for Level 2 EV chargers and lots of ways to install them. This was a description of my journey which one worked for me and why. It also gives you an idea of what installation can be like. Installation charges can vary from a couple hundred dollars to over a thousand if you need to upgrade your electric service.


Bosch EL-5124 Level 2 Charger – Amazon for $792.95 including tax/shipping.

NEMA Pig tail for $23

Electrician bill of $318.60 for 40 amp circuit, 35’ of 8 Guage of wire, and labor

TOTAL: $1,134.55

*For full image gallery of the install, click here.

Categories: Charging

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40 Comments on "Home Installation Of Level 2 EVSE For An Electric Car"

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isnt the charger inside the i3 like other evs?

“….isnt the charger inside the i3 like other evs?…”. Hi BigSolar. I’ve tried to investigate this and the only thing I can say is, I’m not sure, but I’ll give it my ‘best guess’. First off, to meet European efficiency and powerfactor standards, the pf of the car charger in Europe has to be at least .99 (hint: 1 is perfect). Lets not worry about efficiency since I’ve never seen it spec’d for the public. The preferred version (Europe) of the I3 is a Mennekes compatible European Standard of 230Y/400 @ 10 amps, or 7000 watts for the apparently typical German household with 3-phase 400 volt power. The North American version as far as I can gleen is 7200 watts maximum at a maximum of 32 amps, so that if u have at least 225 volts at your garage, (remebering pf > .99), then the car will charge at full power, or in your case, you would just use the very typical ‘charger brick’, what BMW says is an “Occasional Use Charger” 12 amps at 110. I can’t give a more definitive answer since the above was just gleened from reading between the lines on both the BMW and Bosch… Read more »

I’m pretty sure Big Solar’s “question” was just intended to point out that you mistakenly refer to your charge station or EVSE as a “charger”. The charger is where the power conversion happens, and so for AC charging, the charger is the component that’s integrated into the vehicle. For DC charging, the EVSE is itself a charger.

TO the contrary, You’re mistaken that I call the charger my EVSE. He asked CORRECTLY about the charger in the I3 to which I responded. It would be helpful if you learned how to read and UNDERSTAND, since you quite obviously need to re-read the paragraph I typed. I never refer to the EVSE as a charger, unless I put it in quotes as to what the manufacturer calls it. The “charger brick” BMW calls an “Occassional Use Charger”. I’m sorry, but that’s what they call it. All this is silly anyway because In the paragraph I was obviously referring to the thing in the car itself. And in general, I always refer to EVSE things as a “Charger Dock” or Charger Docking Station. Not just you, but so many people here seem to get so uptight over such a simple device. Rest assured, I had to redesign my Schneider Electric unit when their enginneering dept would not assist me in getting it to 1). Work with my Roadster, nor 2). Was interested in the overheating problem the unmodified unit had, which I also took care of? So, when was the last time you FIXED 2 existing problems with an… Read more »
Dr. Kenneth Noisewater
A 240V outlet can charge an electric vehicle twice as fast as the 110V. At least 2x in the worst case (Volt), more like 6x for the best currently-announced non-Tesla case (MB B-class at 10kW vs 1.5kW for L1). When it gets to where electricity meets the EV, the SAE J1772 Charging plug is standard for all electric vehicles except the Tesla cars which have a proprietary charging plug. Thanks Elon! Tesla’s plug and system is superior to J1772 and CCS because: * it combines both AC and DC capabilities in a compact single plug * it can handle up to 135kW DC and 19.2kW AC * the portable EVSE can handle up to 9.6kW and comes with multiple connectors from a typical 12A house outlet to a 50A RV socket * Tesla has a wall connector option for home charging up to the aforementioned 19.2kW AC (80A x 240V 3h rated). * Tesla has the only >100kW charging infrastructure installed, and the only production cars that can handle that much charging power. In my opinion, you need at least 200amp service to your house to be able to add a 40amp circuit. I reckon with efficiency upgrades, I’m good… Read more »
“A 240V outlet can charge an electric vehicle twice as fast as the 110V. ” Actually thats an understatement in every car I’ve seen to date, even my volt which charges in about 1/3 the time at the higher voltage. With my Roadster, I gain 2 miles per hour at 110, and 23 miles per hour at 225. And that’s only using a dinky 30 amp EVSE. When the heat sinks are clean. When they’re dirty, the efficiency of the 110 suffers but not the other, although the charge rate will drop. Incidentally, I haven’t heard anyone try to make this silly point on InsideEvs yet, but I was at an alternative show and this self appointed Omniscient Big Expert Engineer showed up saying I was ALL WRONG since the only thing that counts is P=I^2*R and therefore charging at 110 has to be more efficient than 220, etc and other such nonesence. P does = I^2 *R, But there are also BIG EXPERTS who only learn one formula in their lives and don’t understand how it relates to a car, in that there are more parts in the car charging process than just internal battery resistance. There are also,… Read more »

“I’m fine with my 60A.”

Does this refer to the size of your main electric service, the subfeed for the garage, or your 48 amp clipper creek evse?

“SAE J1772 Charging plug is standard for all electric vehicles except the Tesla cars which have a proprietary charging plug. Thanks Elon!”

Actually, it is more complex. J1772 is mostly American, Europe has a different plug that can support 3 phase AC charging

Yeah, the ‘complexity’ is that Teslas in Europe use a more standardized solution than in the states, surprisingly. But the current adapter I’m told makes it less painful for 2 big reasons:
1). Included free with the car (you don’t have to pay an extra $750 as I did for my Roadster), and:

2). The ‘revised’ j1772 adapter doesn’t shrink in the cold like the first one did so you can actually possibly not get stranded in February and actually use it.

There is a significant problem with your installation. You have put a 50A socket on your 40A breaker. If your friend brings over his Tesla and plugs his UMC into your 14-50 socket, he will trip your breaker. This is not a code violation, but you should just have your Tesla visitor use their J1772 adapter and plug into your EVSE. That is guaranteed to operate at a safe current for your installation. The other option is to tell your friend that you have a 40A circuit and he can turn down the charging current on the center screen to 32A, from the default 40A.

This “Range” outlet is automatically compatible with those cheap first overheating Tesla adapters that automatically dial the current down to 32 amps anyway.

Significant problem? Not in the US. NEC allows 40 or 50 amp Branch Circuites to use this device. Its fine for what he has, and just tell all Tesla dudes to dial it up for 32 amps. Big Deal huh?

Prius Plug-in Commuter

You forgot to include fees associated with pulling permits (unless this was included in your electrician bill). This also varies hugely by city, although I imagine a large number of EV owners don’t pull the permit due to additional costs. And you should mention the differences in amperage related to charging times.

Well, maybe he just wanted the thing to run cooly and to work safely, and didn’t care whether it is permitted or not.

Putting the plug on the Bosch voids all warranties anyways so he’s obviously not worried about that.

Everything about his installation looks fine to me… TO answer his question from his panel, yes he does have room, and with smaller Cutler-Hammer (what was shown here) panels, they now have 1/2 size duplex 110 volt branch brakers so that you can also buy those to free up totally full panels to keep you from getting in a bind and having to “Cha-Ching”.

FWIW Clipper Creek does have a plug version for about $60 extra.

They also have a smaller 24-amp model that costs $100 less, so it’s probably the cheapest option, as well as needing a thinner electrical cable.

24A … are you sure?

Sorry you’re right, it’s the LCS-25 I meant which officially gives 20A not 24A.

But again it would be so much cheaper than the above described process (gauge 10 rather than 8, easier to do it alone, etc. etc.) that it might be worth it. $549 already comes with a NEMA 14-50 plug (or several other plug options), and you can toss it into the trunk, it’s as compact as your L1 charger.

And as said above, the 32A charger is ~$100 more, still the cheapest while being the most powerful.

That LCS looks like a nice EVSE. And if they rework that charger to 24A, and make it 120/240V they will sell many.

But until then, I guess people would rather purchase the TurboCord, because it is more versatile.

“Electrician bill of $318.60 for 40 amp circuit, 35’ of 8 Guage of wire, and labor”

Damn, that Electrician worked cheap.

Green should be the ground wire, and should never be carrying current under normal conditions. The white wire should be neutral. This is in accordance with the NEC. The wiring shown above is potentially dangerous and should be fixed.


Seems fine to me. Red & black are carrying the 240V current. The green is ground. The neutral (white) is not needed in a 240 charger.

The neutral wire will carry any current imbalance in a 240V system. In theory, there should be no current imbalance, but if there ever is one, it should not be on the ground wire. Grounded connections are often left exposed, and if the ground wire is carrying current and someone touches an exposed ground terminal, they could get shocked.

It would be better to connect the white neutral wire and leave the ground wire unconnected. If the device specifies two hot wires and a neutral, then that is the only correct wiring.

Actually, YOUR explanation is Totally incorrect, and would not pass inspection. The charger inside the car runs on either low voltage or high, but does not run on both at the same time.

IF the EVSE does not have a neutral terminal (only one brand does to my knowledge, and this brand only requires a 4-wire supply, and its nothing to do with the car charger in any event, but merely to run the control electronics off 110, while the car runs only at 220 while being used by this EVSE), then hooking up a ‘Neutral’ wire to the Ground terminal (safety ground or “Earth” for our Eurasian friends), you’ve just contaminated your entire wiring system for your whole house.

The other thing is that if u take a grounded (earthed) wire or pipe and lean it against the car which is also connected to this preferably grounded lead, you’ll get a SPARK, since now the neutral current will go back through the car instead of through the wiring.


What you just said makes no sense. The device connections are labelled as L1/L2/N, and you claim that you should connect the N terminal to the equipment grounding conductor so that you don’t run current into your house ground, but that is exactly what this wiring does. If the device connections are labelled as L1/L2/N, then there is no connection for an equipment grounding conductor. The only option in that case is to not ground the device. In this particular case, an equipment grounding conductor is not important because every EVSE has GFCI protection built in. I am not quite sure what code says about that, but you are allowed to put in 120V GFCI outlets that have no ground wire (with proper labeling), so it may be acceptable. It is also the only way to wire the device according to the provided instructions, so I assume that the company making it verified that it is code compliant. There is no way that it is ever correct to wire up two hot wires and an equipment grounding wire without a neutral conductor. Three terminal 240V plugs have two hot and a neutral, with no ground. Four terminal plugs have two… Read more »
No offense man, but you are really going off on a wrong direction and you are hanging your hat on the fact a CHINESE manufactured unit says “N” instead of “G”. Excuse me, but more idiocy: “…There is no way that it is ever correct to wire up two hot wires and an equipment grounding wire without a neutral conductor….”. A corner-grounded (sometimes called Grounded “B”) 3 wire Delta connected service has no neutral in the entire system. It does have the GROUNDING ELECTRODE attached to the center phase, in which case, this is a GROUNDED HOT WIRE, as the only voltage in the system A-B, B-C, or C-A is 120, 240, 480, or 600, on in the medium voltage realm 2400,4800, 6900, 12000, 23000, 34500, etc. On a 240 volt gnd-B system there is no 120 volts, period, and def no neutral. And before you say a grounded hot wire is impossible, what to you say about the negative ground system used for the past 80 years on cars, either 6 or 12 volts? The negative lead conducts just as much current at the positive lead and is just as important, the only thing is, it also happens to… Read more »
Now, the only way this “N” terminal could actually be a Neutral, is if this is a brand of EVSE that actually needs 110 to operate. I’ve never looked inside a bosch, so there is the off chance that you are right about this particular unit. I’ll admit the posibility is there, since this barrier strip seems to be insulated from ground, as it should be. But then the question is, WHY DID THE WRITER WONDER WHERE TO HOOK UP THE WIRES IF THERE WERE TRULY 4 TERMINALS? THERE *HAS* to be a GROUND terminal somewhere clearly hookupable. Why didn’t he see it, and why did the BMW group tell him to hook it up as shown if this is truly a 4 wire device? If it is a 4 wire device, then I’ll take back a portion of what I said. But then you are implying the writer, AND THE WHOLE BMW I3 USERS group is BLIND, and can’t see the 4th terminal. If there are truly only 3 terminals, it should be easy to see if the “N” lead is bonded to the chassis of the Bosch, (and the 3rd heavy lead going to the J1772), and therefore… Read more »

From Bosch PowerMax manual (courtesy EVWEST)

“…569217 | REV. A | 05.22.2013 Bosch Automotive Service Solutions”\


This shows the approved method of hooking up all Bosch PowerMax’s. If you look at the terminal strip in the user manual, it is CLEARLY labeled LEFT TO RIGHT, G, L2, L1.


If you say anything else you are going DIRECTLY against BOSCH’s authorized install procedure.

Now that should do it.

“…Three terminal 240V plugs have two hot and a neutral, with no ground…..”.

In that case call the National Equipment Manufacturer’s Association (NEMA)
and tell them their 6-50 outlets, WHICH ALL LEVITON 30 amp and higher EVSE’S USE, and also the Siemens and Clipper Creek portable units, as well as the plugable Aerovironment, and plugable GE wattStations, are all mistaken since they disagree with you.

They are labeled L1, L2, and G. or else GROUND.

Such Arrogance.

“….New devices are supposed to have connections for two hot, one neutral, and one ground, so I’m not sure why the EVSE only has three connections….”

Says who? You? Gimme a break man.

“…I’m not sure why the EVSE only has three connections….”

Believe me, children shouldn’t be allowed to do electrical work. We heard all this EXPERT opinion from you, and NOW you finally admit you don’t know why things exist the way they do?

This is arrogance in the extreme.

The only ‘cheat’ I see here is the home-converted Bosch unit. And its not much of a cheat since I did the same thing to my 30 amp Schneider EV-Link. Hopefully the Chinese Bosch unit will not have to redesigned to not overheat as my Schneider orginally was.

TO your point, he taped up the unused ‘neutral’ white wire. What else was he supposed to do with it?

Bill, could you tell me what you did to your Schneider EV Link? I just installed mine, and it seems OK other than being a bit cheap-ish and the contactor buzzing at first and one of the terminals not installed correctly and the instructions missing….anyway, I think I’ve heard you refer to it overheating before and I wondered what you did to modify it.

Pretty good, but they left out 2 important points at ‘Bryant Electric’

1). Delta-Connected services have to have the wild phase (i.e. 208 to ground) taped “orange”.

2). The different color schemes MUST be used when 2 different systems appear in the same building, say, a coffee shop with both 277Y/480 and 120Y/208, to avoid confusing systems.

I can understand some of this confusion, as I once wired up a 220V air compressor with 20 feet of flex cable and connected a dryer cord to that, with ring connectors added to the adjoining ends and simply matched the colors! Bolted the staggered rings together, and wrapped them all up with Electrical vinyl tape, plugged into the dryer outlet and watched the empty compressor labour trying but failing in coming up to speed, and started to share that interesting aroma of electrical coating melting, at which point I switched it off with its little bat handle! After unplugging and dissasembling everything and using a multi-meter to trace power, continuity, and colors, I just taped and labeled everything to follow the two hots at 110V, and the neutral and ground wires from the dryer plug back to the compressor! Turns out, I had been feeding one 110V leg to the compressors 1st 110V post, and a Neutral to the 2nd 110V post, while my second 110V feed ended up at the compressors Neutral post!! After the retracing of all the power paths, I reassembled the wires correctly, re-taped up the ring connectors, and tried it again. Success! Full power/RPM… Read more »

The issue here in this article, is that, everything the Article Writer did was perfectly fine (unless you want to split hairs and say he shouldn’t have put a cord on the unit since it voids the warranty, but that’s his business).

Also, all his colors, wire sizes and wiring methods were fine for residential construction.

Its just some of the comments where many posters here would get in trouble with an Electrical Inspector, since its painfully obvious they have no idea what they are doing but only think they do.

Technically, all references to 110V in the article should be replaced with 120V, since each 120V outlet is a split phase from the 240V service feed.

Since the recepticle is not mounted on the green pad transformer on the front lawn, nor the side of the soup can a few poles down the street, there is always some presure drop, and on low voltages the percentage loss is always great. 110 is actually quite accurate since I rarely get more than that when charging my roadster at this pressure. Split-Phase means something entirely different to americans, and only British Utility workers experience it (460 volts on the pole, but 230 volts in the house), so I shun its usage.

Besides, my cable company says to plug the cable box into the 110, so that settles it.

Great article — I actually have the same Bosch charger except mine has the shorter cable. Got it for around $415 during XMAS 2013 from Bosch.

Works great, looks great, and easy to clean and install.

It’s interesting how the “Buy German” seemed to influence your choice. Considering the hardware was over $800 and the warranty was either 1 yr or voided due to the pigtail mod, why you wouldn’t just buy the HCS-40 with Nema 14-50 and a 3 yr warranty +$20 for the holster at ~$570. Then the rest of your install costs would have been at or near the cost of your hardware choice. Also the concept that someone keen on saving money by going electric would waste $300, which equates to 1/2 a years driving, seems illogical. Still, Thanks for the write up. I agree that it’s a topic worth demystifying and educational.

Perhaps the ‘clean white’ squareish Chinese Bosch unit matched to Motif in the rest of his finished Garage.

I’ve never used his model, but I have used the extra cheap 16 amp version, and its fine, working as advertised.

Please could you provide a make/brand or any other details on the 14-50 plug that you mention “I had to add a NEMA Plug which was not included. It cost $23 from Lowes, and can handle 50 amps. A “range” plug they call it” ….I just want to pick the right one. Thanks.

white = neutral , green=ground.