Charging with NEMA 14-50 cable is NOT recommended

4851 Views 13 Replies 3 Participants Last post by Dar, 8 mo ago

Dar

Discussion Starter · Mar 22, 2022

Good day! This may benefit somebody out there searching for if they should just use a NEMA 14-50 cable for charging their beautiful Mercedes. In a word, DON'T!

For quicker charging, more reliable charging, safer charging, more software updates, charging scheduling and other sophisticated features, connection to a smart home, possible savings in the long run and more, go with what Mercedes recommend! Which is a Mercedes recommended charging station professionally installed (in USA by Qmerit). NOT just a basic NEMA 14-50 cable regularly plugged into a NEMA 14-50 outlet!

NEMA 14-50 outlets were not designed specifically for EV charging; they are designed more for plugging in RVs and range ovens! Roast food with them not your EV.

Old NEMA outlets can also age poorly. And newer NEMA outlets in USA with the newer required GFCI breakers can cut out more easily so can be less reliable especially for cars that also have GFCI breakers.

Some other brands may supply a basic NEMA 14-50 cable however they simultaneously might NOT recommend you actually use it, if at all possible! Read in more detail here such a recommendation not to use! -

NEMA 14-50 Tesla Response | Seahurst Electric

Q: How does Tesla respond to NEMA 14-50 questions? A: While an existing NEMA 14-50 outlet will work to charge the car, you would need to purchase the $35 adapter from Tesla to make it work, they are not provided with the vehicle. Tesla does not recommend installing a new NEMA 14-50 outlet to...

www.seahurst.com

As well as basic cables, charging stations can also be plugged into a NEMA 14-50 outlet HOWEVER professional installation hard-wired has fewer failure points! Mercedes recommend professional installation, for example in USA by QMerit for their currently recommended charging station which is the Chargepoint Home Flex. Other countries may have other recommended charging station like Mercedes brand or other brand like in Canada the FLO Home X5 station designed for -40c temperatures.

Buy ChargePoint Home Flex | ChargePoint

www.chargepoint.com

Hopefully after reading this, you are better informed to avoid using just a NEMA 14-50 cable.

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bstringer

· #2 · 8 mo ago

This has not been my experience. I had my adult son install a NEMA 14-50 outlet on a 50 Amp breaker in his garage shortly after I purchased my new 2014 Tesla Model S. I reimbursed him. I used the plug with my Gen1 Tesla Mobile Charger which came with a NEMA 14-50 adapter as well as a NEMA 5-15 adapter for 120 volt plugs. Over the next 8 years I charged multiple times at 40 amps with no issues. I continue to use the same Tesla Mobile Charge Cord with my 2022 EQS580 with the addition of a TeslaTap adapter. Still working without a problem.

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Dar

Discussion Starter · #3 · 8 mo ago

Ideally I would pay an electrician to replace with the standard setup suggested by Mercedes, however I am not saying that NEMA doesn't work. By the way, depending on how install was done and where you live and if your NEMA plug is in garage or outside it may no longer be compliant with a national electric standard and may be flagged on house sale:

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Bruce61

· #4 · 8 mo ago

I don't know where these rumors get started but in the US, there are probably tens of thousands (if not hundreds of thousands) of NEMA 14-50 outlets on the exteriors of homes, or in campgrounds, as this particular variation has been used on RV campers long before EV cars came to fruition. Tesla has sold over a million cars with the charging cable with the most popular plug end being 14-50. It is true that for the past year or so they have not included the "pigtail" end and you had to buy the type of plug that worked in your house. But, my first Tesla model S came with three or four adapters and the second one received in March 2022 I needed to buy the plug for $40 - but I have used the exterior plug, installed by a licensed electrician since 2017 without incident. When I get my EQS 580 which sadly is being held at the port of Los Angeles until they are ready to release 2023's, I will buy a wall charger rather than a non-UL rated adapter discussed elsewhere.

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Dar

Discussion Starter · #5 · 8 mo ago

Yes, there may be lots around but NEMA 14-50 wasn't designed especially for EV charging like the newer wallboxes are. Another advantage of wallboxes to the myriad I already listed above in previous posts is innate customizability and security for example some brands can prevent charging unless owner approves in app. And another is simplicity of equipment required for install (where required)- no need for 4wire cable (instead of 3wire), NEMA outlet, box, cover, GFCI breaker (instead of standard) and adapter.

If home charging at the most typically useful speed (needing at least 230v not 120v), the one Mercedes recommends installing is a wallbox rather than the typical dryer outlet: "Can I charge at home with a standard household outlet? Yes, but it's worth noting that a standard household outlet is a 110V outlet which is far less powerful than a 240V outlet, which is typically found with dryers or can be installed by a licensed electrician. The good news is that having a 240V charging station installed in your home is easy. The ChargePoint Home Flex is the wallbox we’d recommend... In addition, we recommend using Qmerit" (professional electricians) " for installation."

Electric Cars FAQ

Introducing the all-new line of Mercedes-Benz electric cars. Models include the HQ fully electric vehicle, EQ Power plug-in hybrid, & EQ Power+ AMG performance hybrid.

www.mbusa.com

It's not just me AND the experienced Tesla installation manager linked above AND Mercedes FAQ that recommends installing wallboxes. This is an example of an electrician who also recommends wallboxes unless you are poor : "I would only choose a NEMA option if your budget is tight".

Hard Wired EV Charger VS NEMA Outlet - Kuhlman Electrical Services

Hard wired EV charger and NEMA outlets are two options that our customers usually choose between. Learn more about which is best for you from KES.

www.kuhlmanelectricalservices.com

If buying a Mercedes why not buy the Mercedes of home charging solutions? A specially designed wallbox not a cheap common dryer/stove/campsite socket

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Bruce61

· #6 · 8 mo ago

I really do not think you know what you are talking about. This is not about expense. The overwhelming number of wallboxes are sold with NEMA plugs. If they did not recommend it, they would require hard-wiring. Clearly Chargepoint, ClipperCreek and other major manufacturers don't share your opinion.

Of course an electrician will recommend it. He does not want to lose the repeat business.

We are talking about a wall-box plugged into a NEMA plug. It can be 50A or 60A, depending on which plug you want to install (the 60A needs heavier wire in some jurisdictions). So, speed is no different. This is not going to be a cord that is repeatedly plugged in and then disconnected which could, over time, wear down the receptacle. The only real con is about $50 for the added box and plug if mounted outside and about $20 for an interior box and plug; on the other hand, when the wallbox breaks or needs repair of any kind, you must use an electrician to uninstall and then install the replacement/repaired box. Or, if you want to switch types of chargers, like if you go from Tesla to a generic charger, or vice versa, again, the plugged solution is the easiest. This is a no brainer.

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Dar

Discussion Starter · #7 · 8 mo ago

If you read my original post, my main point is comparing hard-wired wallbox to NEMA 14-50 socket without a wallbox.

And Chargepoint DO RECOMMEND hard-wired as there can be complications from GFCI breakers in 2020 National Electric Code compliant NEMA installs! "ChargePoint recommends a hardwire installation. We do not recommend using a GFCI breaker as the Home Flex has charging circuit interrupting device (CCID) protection."

https://www.chargepoint.com/files/en-ca/home/CPH50_InstallGuide.pdf

https://www.dli.mn.gov/sites/default/files/pdf/NECFAQ20.pdf

And regards Clippercreek, the NEMA 14-50 outlet is considered to be safer for use with 40 amp Level 2 chargers. "40 Amps is the maximum continuous load that circuit can handle" (Features section of first link)
Yet "ClipperCreek Level 2 Charging Stations range in power from 12 Amps to 80 Amps (2.8kW - 19.2+kW)".
Not much good for plugging into 14-50 then if you want max speed!

Portable EV Charger NEMA 14-50 / 40 AMP - Splitvolt

40 Amp Portable EV Charger, 240 Volt with SAE J1772 and NEMA 14-50 Interfaces for maximum possible charging rate on a 50 Amp circuit. Free Shipping in the continental US 30-Day Money Back Guarantee

www.splitvolt.com

Level 2 Electric Vehicle Charging Stations: 12-80 Amp | ClipperCreek

Shop ClipperCreek.com for Level 2 charging stations with power ranges from 12 - 80 Amps. Level 2 stations are the right fit for EV owners, fleet operators, businesses and municipalities that want to offer charging to employees, customers and visitors.

store.clippercreek.com

..

I see a contradiction between "This is not about expense" and "The only real con is about $50 for the added box and plug if mounted outside and about $20 for an interior box and plug; on the other hand, when the wallbox breaks or needs repair of any kind, you must use an electrician to uninstall and then install the replacement/repaired box."

But thank you for pointing out another NEMA disadvantage - the deterioration of the plug! With repeated plugging - where applicable

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Bruce61

· #8 · 8 mo ago

Once again, you don't know what you are talking about. One would not use a GFCI breaker for this connection, and the breaker would be the same whether it was directly to the hard-wired wall box, or to the receptacle. Please don't take my comments out of context and I won't do the same with yours. My comment as to the repeated disengaging of the plug was to say this would not be an issue; my comment as to cost was to say it was diminimus, not to say it was an issue.

No matter whether the box is hardwired or uses a plug, a 50A breaker can support a 40A charger (or a NEMA 14-50) and a NEMA 6-50 could support a 60A breaker and provide 50A to the charger. The additional charging speed is only about 3-4 MPH of charging capacity. Many people don't have much room in their electrical panels and need to use four-pole breakers in a 20A/50A/20A configuration as this takes up the same space as two usual 20A breakers. They don't make the same thing with a 60A dual-pole breaker. So this is not an option for many people.

In the end, a hard-wired wallbox looks a bit better. Practically speaking, I cannot imagine there is a single actual benefit to hardwiring rather than a cord to a NEMA outlet other than perhaps keeping someone (like a child) from touching the connection..

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Dar

Discussion Starter · #9 · 8 mo ago

"Practically speaking, I cannot imagine there is a single actual benefit to hardwiring rather than a cord to a NEMA outlet other than perhaps keeping someone (like a child) from touching the connection.."

For the third time, my original main point is comparing hard-wired wallbox to NEMA 14-50 socket without a wallbox, not the advantages of merely not hardwiring or advantages of 6-50 socket to 14-50 or other out-of-context topics. Anyway there are advantages of hardwiring such as less points of failure including locations for wiring to arc. And the GFCI issue is relevant because some socket locations will have required a GFCI breaker, however I understand your point that it may be possible to get around this by relocating where to plug.

I am of course not saying repeated plugging is an issue if not repeatedly plugging or that you think it is a big problem. That is why I write "where applicable", referring to for example people who try to use the one cable for different places, a possible NEMA disadvantage.

And thank you for even more NEMA disadvantages depending on situation - ugly AND a danger to the vulnerable including children AND lower speeds compared to hardwiring wallbox for people not living with cramped electrical parts

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Bruce61

· #10 · 8 mo ago

Dar said:
"Practically speaking, I cannot imagine there is a single actual benefit to hardwiring rather than a cord to a NEMA outlet other than perhaps keeping someone (like a child) from touching the connection.."

For the third time, my original main point is comparing hard-wired wallbox to NEMA 14-50 socket without a wallbox, not the advantages of merely not hardwiring or advantages of 6-50 socket to 14-50 or other out-of-context topics. Anyway there are advantages of hardwiring such as less points of failure including locations for wiring to arc. And the GFCI issue is relevant because some socket locations will have required a GFCI breaker, however I understand your point that it may be possible to get around this by relocating where to plug.

I am of course not saying repeated plugging is an issue if not repeatedly plugging or that you think it is a big problem. That is why I write "where applicable", referring to for example people who try to use the one cable for different places, a possible NEMA disadvantage.

And thank you for even more NEMA disadvantages depending on situation - ugly AND a danger to the vulnerable including children AND lower speeds compared to hardwiring wallbox for people not living with cramped electrical parts

Not worth my time. You are mixing up concepts and are just wrong. People please consult with an electrician in your community and don't rely on his nonsense.

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Dar

Discussion Starter · #11 · 8 mo ago

Bruce61 said:
..
Of course an electrician will recommend it. He does not want to lose the repeat business.
..

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Dar

Discussion Starter · #12 · 8 mo ago

To anyone reading who can comprehend me, consult with Mercedes.

Mercedes recommended Qmerit to me.

Qmerit recommended hard-wire a wallbox instead of NEMA and no wallbox:

Electrification FAQ | Qmerit

Questions on EV charging or other electrification technologies? Get the information you need on products, installation pricing and processes—and much more.

qmerit.com

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And it's not just Mercedes that recommend hard-wire a wallbox. Other car manufacturers like Rivian do too:

Does the Rivian Wall Charger need hardwire installation? - Support Center - Rivian

We designed the Rivian Wall Charger for hardwire installation by a licensed electrician to enable optimal charging speeds. For help with installation of a Rivian Wall Charger, our partner Qmerit can help you find a licensed electrician. Customers can get started with the process by visiting the...

rivian.com

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Though Tesla car manufacturer stockholders would I guess prefer to make it easy use their Tesla wall connector instead of above recommendation which would need an adaptor for Tesla

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