ev charging

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Full guide for charging stations and extension cords to charge electric cars, electric motorcycles, electric bicycles

Your electric vehicle was supposed to transport you around town and beyond. The problem is most electric cars have an 80-100 mile range, and the charging network isn't built out enough for inter-city travel. If you can afford the Tesla Model S or X, you have an inter-city charging network available. The rest of us, who can't afford $100,000 cars, don't have to be limited to traveling a short distance from your home. We can take longer trips either by using the charging network or plugging into available power outlets.

Successfully traveling long distances with an electric car travel means having the flexibility to use any power outlet you find, and the equipment to maximize the charging rate. You must develop the skills understand some simple rules for safely using and building extension cords and adapter cables matching any power outlet.

The public charging network, and informal use of power outlets

Currently (2015) the public charging station network isn't enough to let us freely drive our electric vehicles anywhere we want. Most cities have public level 2 and even fast charging, but the inter-city charging network is weak. Even though electricity is everywhere, the electricity has to be adapted into a charging plug for recharging the car. The good news is we don't have to be limited to the public charging station network. There are plenty of high power electrical outlets available, and with the right equipment (see list below) we can snag a 6 kiloWatt charging rate for a fairly reasonable charging time.


The car manufacturers provide a 120 volts 12 amps (1.2 kilowatts) line cord charger with each car. While that unit is better than nothing as a fallback charging source, there are several choices offering higher power charging. (see list below)

The outlet shown to the right, a NEMA 14-50 outlet, is the primary objective because this, and other similar outlets, will provide up to 240 volts 40 amps continuous power. That's enough, with a 6 kiloWatt charging station, to provide 25 miles of range per hour of charging. (see a list of portable charging stations below) With a portable 6+ kiloWatt charging station, along with adapters and extension cords, will allow a respectable charging rate (25 miles per hour of charging) at any power outlet you find. Such as at a laundromat or RV park.

Wait, isn't it dangerous to use an extension cord to charge a vehicle?

Is it safe to use extension cords and adapters to charge an electric car? Yes, with care. Can you charge an electric car from a dryer outlet? Yes, with care. The short answer is using a good quality extension with thick wires and beefy plugs. In the lists below we show several choices for 120 volt 10 gauge extension cords that are safe for use with a line cord charger, and several 240 volt 40 amp extension cords safe for use with higher power charging stations.

The general principles are:

  • Check carefully the power socket rating
  • Check carefully the wiring to the power socket
  • Use heavy duty cables with high enough gauge to handle the current
  • Don't use cables that are frayed or broken
  • If you can, adjust the vehicle charger to not draw more current than you know is safe
  • Your power is limited by the weakest link in the chain - don't draw more through a circuit than its rating
  • Check whether cords or connections are getting hot while in use
  • Use the shortest length of cord possible

Where does the heat come from in a substandard situation? A skinny cord, frayed wiring, bad power socket, acts like a "resistor" or "heating element". Sending too much current through a bad connection acts like a heater. Say your car is pulling 6 kilowatts, a 10% loss from a bad connection means 600 watts being dissipated as heat, or about the same as a typical hair dryer.

Avoid violating Electrical codes Smart electricians and electrical engineers have spent decades cooperatively developing the electrical code. Their recommendations were won through hard work and the occasional electrical fire. It's easy to create adapters to connect a 240 volt 50 amp device to a receptacle rated for 120 volts 20 amps. That's obviously not to work terribly well. Running 6+ kilowatts through a 120 volt 20 amp plug is obviously a problem. The device for which you create such an adapter must accommodate dual voltages and automatically adjust its power.

Your fate is in your hands - this is for educational purposes. I am offering this for education, and you are responsible for your actions. Applied incorrectly this can cause electrocution or fire. A 240 volt 50 amp outlet is capable of sending 10 kilowatts of electricity. Take care, be smart and educated, and you'll be okay.

Your best bet is using approved charging stations and approved on-board chargers - but we often have to "make do" with whatever electrical outlet we find. The manufacturers have spent megabucks developing a safe charging system. BUT, unfortunately, we cannot always charge through approved charging stations, and we often are faced with normal power outlets. High power portable charging stations do exist, but successfully using one means understanding what kind of power outlet to use, and using adapters to adjust for the power outlets we find in the wild.

You might find in actual practice that using long skinny extension cords just results in a warm cord, with no fire. That was claimed in a discussion on this site several years ago. But electrical fires due to frayed worn cords are common enough that we should be cautious. We want our electric car in the news because it saves the planet, not because a building burned down while charging.

The need for safety: Done badly, possible to cause damage. The manufacturers usually warn against using extension cords to charge an electric vehicle. With care you can safely ignore that warning, but of course you must know what you're doing. There have been multiple fires from electric cars being charged through substandard wiring. How? Bad wiring can easily cause enough heat to raise surrounding materials to the ignition point. With good quality extension cords and adapters, you can charge electric vehicles anywhere there's electricity. We bought our electric vehicles to, for example, help the climate. Getting on the evening news by causing an electrical fire negates the gain you might have achieved.

JLong - the best choice for an electric car extension cord

Regular household extension cords are tricky to use with an electric car. They probably aren't designed for the continuous load required for electric car charging. What's needed is an extension cord with thick wires, good quality connectors, a robust design, that works correctly with the charging outlet. A very common need is to plug into a charging station that's blocked by another car. Therefore, the correct extension cord must extend the J1772 connection and not the power outlet.

Normal extension cords extend the power outlet - they plug into a regular power outlet, providing a matching outlet on the other end of the cord. It's great for using a power tool in the back yard, but not so good for electric car charging. A J1772 extension cord would have a J1772 socket on one end and a J1772 plug on the other.

The JLong 40 amp J1772 extension cable is exactly what's needed. This is clearly the best designed J1772 extension cord available. Most importantly the JLong supports a 40 amp charge rate continuous, where other J1772 extension cords max out at 32 amps. It means the wires are thicker, and the connectors more robust, making JLong use a safer choice than the others. The connectors are solid and robust, and the cable is flexible enough to easily loop into a small bundle that's easy to carry in the trunk. Finally, there's a small but important detail - the charging handle can be locked using a simple padlock, that's provided with the JLong. This means your car won't be unplugged unexpectedly or at the very least the JLong won't be stolen.

J1772 extension cords are useful any time the charging cord isn't long enough to reach your car. Maybe you've been blocked from a charging station, but can park a couple stalls down. The JLong gives extra reach.

Other extension cord choices for electric cars

The JLong isn't the only electric car extension cord choice. You can also safely extend the other side of the charging situation connection using a more traditional extension cord. This must be done with care, using extension cords meant for heavy duty usage. Fortunately these do exist.

120 volt cords for the line cord charger Every electric car comes with a 120 volt line cord charging station. Generally these run at 12 amps 120 volts, meaning the extension cord must be capable of running that much current continuously. Scroll down to the bottom of this page and you'll find a few such choices. If you're looking at extension cord packages in the store, study the writing carefully. It'll say the cord is rated for 10 amps, 15 amps, whatever, and that the cord is 12 gauge, 14 gauge, or whatever. The smaller the gauge number the thicker the wire - 10 gauge is the minimum recommended for this purpose. Again, scroll down to the bottom of this page and you'll find several extension cords meant for contractors.

240 volt 20 amp extension cords The Aerovironment TurboCord is an excellent choice offering a 3 kiloWatt charging rate in a tiny package and easy adjustment to support 120 volt or 240 volt outlets. Scroll down to the bottom of the page and you'll find NEMA 6-20 extension cords that will work perfectly with the TurboCord.

You can connect the TurboCord to a high-power outlet by building an adapter. Instructions are shown later for building an adapter cord - it's simply buying a 6-20 socket (see below) and a plug matching the socket you want to use, and a short piece of wiring. The wiring should be either 10 gauge or 8 gauge, and as short as possible.

240 volt 40 amp extension cords For higher power 6+ kiloWatt charging stations, you'll need a heavier-duty extension cord. Scroll to the bottom and you'll find several NEMA 14-50 extension cords. These handle 40 amps continuous and will do what you need. Most (all) of the charging stations shown here come with NEMA 6-50 plugs rather than 14-50 plugs. That means buying a NEMA 6-50 to NEMA 14-50 adapter, several of which are shown below, or else replacing the NEMA 6-50 plug from the charging station cord with a NEMA 14-50 plug.

Luggable and Portable high power charging stations

All electric cars have J1772 ports for normal "level 2" charging, using single-phase AC power. The good thing is this connector is common across North American electric cars. In Europe a different socket is used, but with the same J1772 charging protocol. Any place you can access 240 volts 40 amp continuous electric service gives the possibility of 6+ kiloWatt charging rate for 25 miles range per hour of charging. If, that is, you carry a suitable charging station.

All electric cars are sold with a line charger meant for trickle charging. In North America they typically run at 120 volts 12 amps, and in Europe at 240 volts 12 amps. The 120 volt 12 amp rate adds up to 1.5 kilowatts, which is good for 4-6 miles of range per hour of charging. If that's all you can find it's better than no charging at all. While traveling we'll want faster charging because we have better things to do with our time. Many people use this for home charging with no worries.

It's possible to have the line charger upgraded - http://evseupgrade.com does so for a fee. But the there are several low cost 240 volt portable chargers now, therefore the EVSEUpgrade service is less necessary than it was a couple years ago.

We can't always find a regular level 2 charging station to use while on the road. That's when wehave to make-do, such as stopping in an RV park to use one of their power outlets. To get 6.6 kiloWatt charging means buying a small/portable charging station. These do exist and a few are listed below. Those with a plug pre-attached have a NEMA 6-50 plug, meaning an adapter is required to use a NEMA 14-50 outlet. Such adapters are readily available, and listed below.

Unfortunately few of the 240 volt charging stations operate at 120 volts, and even fewer allow the user to adjust the power. Instead a 240 volt 30 amp charging station will always try to pull 30 amps, which would trip a 20 amp circuit breaker if that's the outlet you find.

Here are a few portabilizable charging stations

Leviton EVBL2-P18 Level 2 Evr-Green Mini, Wall Mounted with Cord, 18': At 20.9 x 3.2 x 1.8 inches and only 2 lbs weight, this is a highly portable charging station. That's about the same size as the line cord charger, but it supports a 5.7 kiloWatt (24 amp) charging rate. Between the small size and the power level, this is close to the perfect portable charging station. It comes with a NEMA 6-30 plug attached to the end of the cord, so make sure you get or build appropriate adapters.


Clipper Creek EV Charging Station 240V 7.7kW/32A 25FT Cord: At 19.7 x 5.3 x 8.9 inches this one is fairly portable, and it runs at the full 6+ kiloWatt charging rate. It comes fitted with a NEMA 6-50P Plug, meaning a NEMA 14-50 adapter is highly recommended. Clipper Creek is a highly recommended company with over a decade of experience building charging stations.


AeroVironment TurboCord Dual Plug-in EV Charger, 120 & 240 Volt: This charging station does it all. It's very compact, and a switchable plug automatically changes it between 120 volt 15 amp or 240 volt 20 amp power outlets. The 240 volt plug is a NEMA 6-20, for a 3 kiloWatt charging rate, and it's straightforward to build adapter plugs to connect with other kinds of power outlets. It's compact and light enough to carry all the time, while supporting higher power charging than the 120 volt manufacturer-supplied charger, and while supporting use at a 120 volt outlet. AeroVironment also has over a decade of experience building electric car charging stations.

[ebay.com] [homedepot.com]

JuiceBox 40A Plug-in Electric Vehicle L2 Home Charging Station with 24-foot cable and NEMA 14-50 plug: At 10" x 6" x 3.5" this charging station packs a lot of power in a small box, supporting full power charging in a tiny unit. The design is more-or-less open source, meaning the Electric Motor Werks website has published enough information about the innards so you can hack on and modify the unit. That includes the ability to add a knob to control the charging rate.


Portable Electric Vehicle Charger by ReadyCharge (240V) - Level 2 Electric Car Charger- Faster Charging Speeds - Compatible with Chevy Volt, Ford Energi, Toyota Prius & Plug-In EVs This extremely small and lightweight charging station is easy to carry in the car at all times. It supports a higher charging rate than the line-cord charger, but the charging rate is limited to 3 kiloWatts. It comes with a NEMA 6-20 plug on the cord.

EVI Plug-in EV Charger -Portable Cord- (US, Europe & Asia): This is a properly portable charging station, with a small size and light weight. Unfortunately it is limited to 220V, 16A, 3.84 kw or 110V, 16A, 1.84kw, so the charging rate is not as fast as some of the others. Since it comes with L6-30, you'll need adapters for the more common NEMA 14-50 and NEMA 5-20 outlets.

Bosch EL-50600-B Power Xpress 240V Charging Station with Cord Holder Out of the box this charger supports a 30 amps charging rate, but it is easy to adjust the charging rate using a knob hidden under an access panel. If you find yourself at a lesser power outlet, simply access that knob and turn the charging rate down. At 23.9 x 9.5 x 7.2 inches it's more portable than some others.

Legrand L2EVSE30 EV Charging Station EVSE Charger w- J1772: At 16 x 5 x 14 inches this charging station is almost properly portable.

Bosch EL-51253 Power Max 30 Amp Electric Vehicle Charging Station with 18' Cord: At 21.2 x 21.2 x 9.2 inches and 20 lbs weight, this charging station is what we'd call "luggable" rather than "portable". It has a 3-conductor cord, so you'll have to add a NEMA 14-50 plug. Once you do, it's easy to unplug this from the wall and carry it in the car.

Blink HQ 30-Amp Home Electric Vehicle (EV) Charger.: At 21 x 9 x 21 inches this too is also a luggable charging station. It's easy to add a NEMA 14-50 plug and carry it in the car.

Leviton EVB40-PST Evr-Green 400 EV Charger, 40-Amp, Surface Mount, 25-Foot Cord, Requires 50Amp Circuit: At 24 x 16.2 x 9 inches this is still a luggable charging station. Because it runs at 40 amps this charging station is very important for owners of cars that run at a higher charging rate, such as the Gen2 Toyota RAV4 EV or the Honda Fit EV.


Siemens VC30GRYU Versicharge 30-Amp Electric Vehicle Charger with Flexible Indoor/Outdoor and 20-Feet Cord: At 16.5 inches by 16.5 inches by 6.5 inches this is more portable than some of the other charging stations. There are several versions of the Siemens Versicharge charging station, and this one comes pre-configured with a NEMA 6-50. It'll be simple to build an adapter so it can be used with NEMA 14-50 outlets.


EVoCharge EVSE 30 Amp (7.2 kW) Level 2 EV Charger, Outdoor Rated, UL Safety Certified, 18 Ft. Cable with Connector Holster, Plug-in or Hardwire, 2yr Warranty, Charges up to 8X Faster than a Standard AC Level 1 Electric Vehicle Charging Station: At 10.5 x 4.7 x 15 inches this is a portable charging station. Because it comes with a NEMA 6-50 Plug plug, a NEMA 14-50 adapter is highly recommended.

The JESLA charger from Quick Charge Power. This is a modified Tesla portable charging unit that has a J1772 cord. It supports switchable plugs to automatically change the power level, and can run up to 240 volt 40 amps. It's also very pricey.
The OpenEVSE is an open source portable charging station which you can build from a kit and whose power level is easily changeable from the front panel. The result does everything we want in a portable high power charging station, and at a reasonable price.


EV Electric Car Type 2, mode 2 portable charging cord 13 A, IEC E13, IEC 62196, EMC (2004/108EC): This is for use in Europe, and is an alternative low power charger to the one supplied with the car.

What about electric bicycles, electric scooters or electric motorcycles

While in some cases these vehicles charge via a J1772 charging cord, it's common to charge them via regular power outlets. If the vehicle uses a J1772 cord, refer to the previous section. If it uses a regular power outlet, you simply need to carry extension cords and regular power adapters.

Increasing the charging rate with any of these probably means using a different charging unit than was provided by the manufacturer. You'll need to understand the charging characteristics of the battery pack.

For example - Zero Motorcycles still sells their bike with a paltry 1 kiloWatt on-board charger, which would mean over 10 hours charging time. A common modification is to adapt the Elcon 2500 charger, or even carry multiple Elcon's.

Using a portable electric car charging station with a regular extension cord

Another situation you might find is an inability to park near the power outlet. While you could use the JLong to extend the reach of your portable charging station, you might prefer to insert an extension cord between the charging station and the power outlet.

If you look at the bottom of this page, in the shopping area, you'll find NEMA 14-50 and NEMA 6-50 extension cords at a reasonable price. They should work well, have wire that's thick enough to avoid getting a hot wire, etc.

There are two considerations to doing this safely, both of which necessitate using an extension cord with thick gauge wire.

  1. Will the cord handle the current?
  2. The voltage drop over the length of cord

As we'll see in the next section, a thick power cord carries more power than a thin cord. Do yourself a favor, avoid the risk of fire, and get a heavy duty cord.

Voltage drop has to do with the resistance of the power cord. The longer the cord, the higher the resistance, and the more voltage will drop over the length of the cord. Using a heavy duty cord decreases the resistance, and therefore decreases the effect of voltage drop. There are two cures to voltage drop, one is to use a short cable run, and the other is to use heavy duty power cable.

How thick of a wire to use?

In the interest of safety, we must use wire of the correct thickness to carry the current. The 6 kilowatt charging stations require 30+ amps of current, for example. This chart shows that a 30 amp continuous circuit requires wire thickness of at least 8 gauge.

Screenshot 2015-03-02 at 20.31.30.png

Common power outlets

Generally speaking single phase AC power is what we'll use to charge electric vehicles. It comes in either 120 volt or 240 volt varieties, either 50 hertz or 60 hertz frequency.

In all cases the power outlet and matching sockets will have either 3 or 4 wires. The 3-wire connectors have two "hot" lines and a ground line, while the 4-wire connectors add a "neutral" wire. There are also ungrounded 2-wire plugs.

We go into more details below - but, if you followed the recommendation above (add a NEMA 14-50 plug to the charging station cord) you'll need to build adapters between NEMA 14-50 and whatever power outlets you need to use. You'll also have to make sure the charging station won't draw more power than the rating on the power outlet. That is, don't plug a 32 amp charging station into a 15 amp outlet because something will catch on fire if the circuit breaker doesn't blow.

In any case, building the adapter is simple - get a short piece of 3-wire thick power cord, and strip off the ends exposing bare wire. Get a 14-50 plug and a socket matching the the power outlet. Connect wires to matching connectors on plug and socket such that the ground's are connected together, and the two hot wire's are connected. That's it.

Choosing the correct plug

We've shown here the NEMA 14-50, but you should choose the plug which fits the power outlets available to you. There are several considerations to be aware of.

The "80% rule" says that continuous power through a plug/socket has to be 80% of the rated value. The NEMA 14-50 is rated for 50 amps, but the 80% rule says to limit it to 40 amps continuous. That means all the charging stations shown above must be used with at least a 40 amp plug/socket combination, and 40 amp circuit breaker (for a 32 amp charging station).

The 14-50 is a commonly available outlet - for example at most RV parks - making it not only widely available, but powerful enough for the charging stations shown above. But maybe the power outlet you'll be using isn't wired with NEMA 14-50, but some other 40 or 50 amp or more outlet. If so, get a matching plug or else build an adapter between 14-50 and this other plug.

We said this earlier, but don't plug a 32 amp charging station into an outlet rated for 20 amps. A 20 amp outlet can only be used for 16 amps continuous, and the 32 amp EVSE is twice that amount. The circuit breaker should do it's thing and trip before a problem occurs. On the other hand, a charging station with adjustable power level can be used on a lower power outlet.

Suppose you do arrive at a 20 amp power outlet? Most of the charging stations above don't allow you to adjust the power level, and therefore you'd be stuck unable to charge. But a charging station supporting adjustable power is helpful, because you simply turn the knob to match the power capability of the outlet you're using.

Another factor is the charge rate supported by your car. Many cars, like the Chevy Volt or Chevy Spark EV, only support a 3 kiloWatt charging rate. You could buy a 6 kiloWatt charging station, and plug it into a 50 amp outlet, but that doesn't magically make your car charge at a higher rate. Even when using higher power equipment, cars supporting 3 kW charging will use at most 3 kW of power.

United States of America, maybe Canada and Mexico

There are two basic classifications of NEMA device: straight-blade and locking. The straight-blade 5–15 and 5–20 are found nearly everywhere in countries using the NEMA standards, and are intended for supplying lighter-duty, general-purpose electrical devices. Twist-locking types are used for heavy industrial and commercial equipment, where increased protection against accidental disconnection is required. Numbers prefixed by "L" are curved-blade, twist-locking connectors; others are straight blade and non-locking. The metal conductive blades are sometimes informally called "prongs" (as in "3-prong plug").

These two charts show the common single-phase AC power outlets. There are additional plugs for 3-phase AC and for 277 volts, but those are uncommon.

120 volt locking 120 volt, 15A, NEMA L5-15 L5-15.gif 120 volt, 20A, NEMA L5-20 L5-20.gif 120 volt, 30A, NEMAL5-30 L5-30.gif
120 volt flat blade 120 volt, 15A, NEMA 5-15 5-15.gif 120 volt, 20A, NEMA 5-20 5-20.gif 120 volt, 30A, NEMA 5-30 5-30.gif 120 volt, 50A, NEMA 5-50 5-50.gif
250 volt locking 250 volt, 15A, NEMA L6-15 L6-15.gif 250 volt, 20A, NEMA L6-20 L6-20.gif 250 volt, 30A, NEMA L6-30 L6-30.gif
250 volt flat blade 250 volt, 15A, NEMA 6-15 6-15.gif 250 volt, 20A, NEMA 6-20 6-20.gif 250 volt, 30A, NEMA 6-30 6-30.gif 250 volt, 50A, NEMA 6-50 6-50.gif
250 volt locking 4-wire 250 volt, 20A, 4 wire, NEMA L14-20 L14-20.gif 250 volt, 30A, 4 wire, NEMA L14-30 L14-30.gif
250 volt flat blade 4-wire 250 volt, 30A, 4 wire, NEMA 14-30 14-30.gif 250 volt, 50A, 4 wire, NEMA 14-50 14-50.gif 250 volt, 60A, 4 wire, NEMA 14-60 14-60.gif

Screenshot 2015-03-02 at 18.36.19.png

"NEMA simplified pins" by Orion Lawlor - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:NEMA_simplified_pins.svg#mediavie...

Great Britain and the former British Empire

Much of the former British Empire adopted the British electrical plugs.


"BS-546-3-pin-plugs" by Original uploader was Ziltro at en.wikipedia - Transferred from en.wikipedia; transferred to Commons by User:Liftarn using CommonsHelper.. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:BS-546-3-pin-plugs.jpg#mediaviewe...

This plug, and the matching socket, handles 240 volts at up to 30 amps. The largest shown here is 15 amps.


"Moulded and rewireable BS 1363 plugs (horizontal)" by Deucharman - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Moulded_and_rewireable_BS_1363_plugs_(horizontal).jpg#mediaviewer/File:Moulded_and_rewireable_BS_1363_plugs_(horizontal).jpg

These are rated for 240 volts 13 amps. Some variants let you open the plug to rewire it, while other variants have fuses in the plug.

Europe, the Europlug

Common across Europe are plugs with two or three round pins like this:


"Schuko plug and socket" by Chameleon, bran & plugwash - This file was derived from:Schuko (CEE 7-4) rewirable 2.jpg:Steckdose.jpg:Steckdose.jpg was scaled up to 200% of its original size to bring the images to roughly the same scale. Portions of the images were then combined.. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Schuko_plug_and_socket.png#mediav...

Adapting a charging station to NEMA 14-50 or other common plug

Many of the charging stations shown above don't come with a plug on the end of the power cord. The manufacturer's manual will tell you the charger must be hard-wired to a junction box, instead of connected via a plug. It's safer to hardwire the thing - a plug you're constantly plugging in and unplugging will eventually go bad, right? And, a plug that's gone bad is a fire waiting to happen.

On the other hand, hard wiring your charging station means you can't carry it along on a trip. Hence, if you want portability and flexibility, add a plug to your charging station, or select one that has one already wired up.

Let's take a look at what's required to attach a NEMA 14-50 to a typical charging station.


This is the standard wiring for a 240 volt device hard-wired to the power system. Two lines are "hot," meaning they carry the AC power, the third wire is ground, and the fourth wire is neutral. Between the two AC wires is 240 volts. Between either of the hot wires and neutral is 120 volts.

For our purposes we're only going to consider the two hot lines and the ground line. That's because the power cord on every charging station uses three wires, two hots and a ground. The standard color coding for the wires is that GREEN is ground, and the two hot lines are RED and BLACK.


This diagram should help clarify the wiring.

Once you get a plug in your hand, it'll be obvious how to match the three wires with the pins on the plug. All you do is to carefully strip the insulation from those wires, then attach the wires to the matching connections on the plug. For most plug designs you loosen a screw, stick the wire into a hole, then tighten the screw.


Unfortunately there are a plethora of power outlets for 240 volts, in the U.S. and perhaps elsewhere. It means that while all single phase AC power outlets have the same kind of power, if the plug on your power cable doesn't match the power socket you're out of luck. Unless you build an adapter.

Fortunately all single phase AC power outlets use three wires (sometimes four) whose purpose is the same: Two wires are "hot" (carry the AC voltage), one wire connects to ground, and the optional fourth wire is neutral. As we said above, for our purpose we'll only focus on the two hot lines and the ground line, and will ignore the neutral line.

Generally speaking, building any adapter follows these steps:

  • Get a short length of 3-wire cable of the appropriate gauge, the thicker the better
  • Strip the ends so you have bare wire - for some adapters you'll only strip one end
  • Open up and study the plugs for each end of the adapter, making sure you understand where the two hots and neutral are
  • Insert the stripped ends into the plugs, tightening down screws, making sure the connectors on each end match up correctly
  • Tighten down strain relief, and otherwise reassemble the plugs at each end


That's what one end of a fairly typical adapter might look like.


And this is a couple completed adapters. At one end is a NEMA 14-50 enclosure - because the charger system in my car uses NEMA 14-50 plugs. The adapters shown here are for the L6-30 (240 volt 30 amp) and 6-20 plugs (240 volt 20 amp).

NEMA 6-50 to NEMA 14-50 adapter for common charging stations

Many of the charging stations shown above have a NEMA 6-50 plug on the end of the power cord. That plug supports 240 volts at up to 50 amps (40 amps continuous), which is great except for one thing. The typical outlet at an RV park is a NEMA 14-50, necessitating an adapter. Which gives us a chance to go through a practical demonstration of building an adapter cable.

The 14-50 connector uses four wires, while the 6-50 connector uses three. In wiring the adapter we'll simply skip wiring the neutral line of the 14-50 to anything.

NEMA 6-50 to 14-50.jpg

This is the wiring connections to make - ground-ground, hot1-hot1, hot2-hot2. In fact, these are the wiring connections for any plug/socket adapter.

At the end of the charging station power cord is a 6-50 plug, meaning one end of the adapter must have a 6-50 socket. At the RV park is a 14-50 socket, meaning the other end of the adapter must have a 14-50 plug.

In the shopping guide below are two choices with a 14-50 plug already attached to a length of heavy-duty power cord. This makes the adapter trivial to build, because you only need to procure a 6-50 socket and wire it to that cord. Which, you'll find below.

You'll also find a couple pre-built adapter cords with a 6-50 socket and 14-50 plug all wired up and ready to go.

Ground Fault protection

Charging an electric vehicle is almost certainly going to happen outside. It might be raining. Water and electricity is of course a bad idea. GFCI plugs are designed to make it safe.

120 volt 20 amp Voltec 04-00102 12/3 STW 20 Amp GFCI Power Block Adapter with Lighted End, 3-Foot, Blue with Yellow Stripe: 20 amp in-line GFCI adapter with lighted power block, length: 2ft, gauge: 12/3, wire type: STW, 3 outlets, plug type: 5-15P, receptacle type: 5-15R, 20 amps, rating watts: 1875.

In other words, this is a short extension cord with GFCI. It's only suitable for a level 1 charger, but will be good insurance.

120 volt 20 amp Tower Manufacturing 30396500-08 20 amp Line And Load Side User Attachable In-Line GFCI With Manual Reset: This unit fits over a cord, giving you strong protection from the elements, while providing GFCI protection.

120 volt 20 amp Leviton WT899-W 20-Amp 125-Volt SmartLock Pro Slim Weather-Resistant and Tamper-Resistant GFCI Receptacle, White: A regular power outlet with GFCI protection. For use in the field, you can install this in a junction box and run wiring into it. However, it's little better than the extension cords, and of course this is limited to level 1 charging.

120 volt 15 amp Tower Manufacturing 30339005 15 amp 3-Wire GFCI Outlet Adapter: 15 amp 3-wire ground fault circuit interrupter (GFCI) outlet adapter for converting standard indoor electrical outlet into GFCI outlet to protect from shock, electrical fire or electrocution

This is an in-line plug/socket making it a little simpler to use than an extension cord. However, it's only rated for 15 amps limiting its usefulness somewhat.

0 volt 0 amp Farm Innovators CC-2 Cord Connect Water-Tight Cord Lock - Green: This is not a GFCI protector at all, instead it fits over cable connections, giving strong protection against the elements.

240 volt 30 amp Square D by Schneider Electric QO230GFICP QO 30-Amp Two-Pole GFCI Breaker: Circuit breakers provide GFCI protection behind the power socket. Where the manufacturers don't seem to build higher power extension cords with GFCI, you could build a junction box containing one of these GFCI circuit breakers, to get portable GFCI protection. This one supports the low end of Level 2 charging.

Double Pole GFCI Circuit Breaker, 60 Amp supports the 240 volt 50+ amp rate necessary for high power charging at the upper end of Level 2.

Square D by Schneider Electric HOME250SPA Homeline 50-Amp Spa Panel provides you with the circuit breaker built into a weatherproof junction box, at a very reasonable price, ready to go. This is meant to be mounted on a building to protect something like a hot tub. At 9.6 x 5.3 x 4.4 inches in size and about 5 lbs weight, I see no reason it couldn't be carried around especially for long trips.

Commercially built adapters

NEMA 14-50 to TT-30P Camco 55185 PowerGrip 30M/50F AMP 18" Dogbone Electrical Adapter with Handles 3750W/125V: This adapter converts between NEMA 14-50 and NEMA TT-30P (30 amp). Camco 55175 18" PowerGrip Dogbone Electrical Adapter with Handle does the same conversion, but reverses the gender of the two ends.

NEMA 6-50 to L14-30 Conntek PL1430650 Welder Adaper Generator L14-30 Plug( 4 Prong 30Amp) to NEMA 6-50R 50 Amp 250-volt Adapter Cord

NEMA 6-50 to L14-50 Conntek P1450650 Welder Adaper Generator/RV 14-50 Plug to NEMA 6-50R 50 Amp 250-volt Adapter Cord

NEMA 6-50 to L14-50 Direct 4 Prong to 3 Prong Adapter Cord, Full Kva 230V

NEMA-L5-20R to NEMA-5-20P, 120 volt 20 amp Tripp Lite P044-06I 6 inch 12AWG Heavy Duty Power Adapter cord (NEMA-L5-20R to NEMA-5-20P): 6-inch 12AWG Heavy Duty Power Adapter cord (NEMA-L5-20R to NEMA-5-20P). Locking 120V 20A (NEMA L5-20R) output receptacle and a straight-blade 120V 20A (NEMA 5-20P) input plug

NEMA L14-30P to NEMA 14-50R, 240 volt 30 amp Conntek RV Generator Adapter with 30 Amp 4 Prong Locking Male Plug To RV 50 Amp Female Connector

NEMA L14-30P to 6-15/20R Plug Adapter NEMA L14-30P to 6-15/20R Plug Adapter - 1 Foot, 20A/250V, 12/3 AWG - Iron Box # IBX-1462-01 This adapter allows you to connect a NEMA 6-20 device to a L14-30 socket. It uses 12 gauge wire, and is rated for 20 amps

30 Amp NEMA 14-30P 4 Prong Male Plug To 30 Amp 125/250 L14-30R Volt Locking Conntek 14330 1.5-Foot Adapter 30 Amp NEMA 14-30P 4 Prong Male Plug To 30 Amp 125/250 L14-30R Volt Locking Female Connector Another adapter cable, between NEMA 14-30 straight pin to NEMA L14-30 locking.

Sockets and Plugs

NEMA 14-50 - 240 volt 50 amp Camco 55353 50 AMP Female Replacement Receptacle and Camco 55255 50 AMP PowerGrip Replacement Plug are excellent choices for NEMA 14-50 cords

NEMA 14-50 - 240 volt 50 amp Leviton 55050 50 Amp, 125/250 Volt, NEMA 14-50R, 3P, 4W, Surface Mounting Receptacle, Straight Blade, Industrial Grade, Grounding, Side Wired, Steel Strap, Black

NEMA 6-50 - 240 volt 50 amp Leviton 5378 50 Amp, 250 Volt, Surface Mounting Receptacle, Straight Blade, Industrial Grade, Grounding, Black: The socket required for building an adapter cord for the NEMA 6-50 plug used on the charging stations shown above.

NEMA TT-30P Camco 55283 30 AMP Mini Replacement Male Plug with PowerGrip Handle and Camco 55343 30 AMP Female Replacement Receptacle

NEMA L14-30 - 240 volt 30 amp 4 pins Socket, NEMA L14-30 30 Amp, 125/250V Twist Lock and Leviton 2711 30 Amp, 125/250 Volt, NEMA L14-30P, 3P, 4W, Locking Plug, Industrial Grade, Grounding - Black-White

NEMA L6-30 - 240 volt 30 amp Leviton 2621 30 Amp, 250 Volt, NEMA L6-30P, 2P, 3W, Locking Plug, Industrial Grade, Grounding - Black-White and Leviton C2623 30 Amp, 250 Volt, NEMA L6-30R, 2P, 3W, Locking Connector, Industrial Grade, Grounding, Black-White

NEMA L6-20 - 240 volt 20 amp Leviton 2321 20 Amp, 250 Volt, NEMA L6-20P, 2P, 3W, Locking Plug, Industrial Grade, Grounding - Black-White and Leviton 2323 20 Amp, 250 Volt, NEMA L6-20R, 2P, 3W, Locking Connector, Industrial Grade, Grounding - Black-White

NEMA 6-50, 6-30, 240 volt, 50 amp, 30 amp Cooper Wiring Devices S42-SP-L Commercial Grade Angle Vinyl Power Plug with 30/50-Amp, 250-Volt, 6-30/6-50-NEMA Rating, Black: The commercial grade angle power plug has feature dual current model furnished with blades. Terminals have pressure plates to protect wires. This device is constructed of abuse-resistant thermoplastic. 30/50-amp, 250-volt, 6-30/6-50-NEMA rating and 3-pole, 3-wire grounding configuration. Available in black color. Measures 2-7/8-Inch length by 1-3/8-width by 3-3/8-Inch height.

NEMA 6-30P 240 volt, 30 amp Leviton 931 30/50 Amp, 250 Volt, Plug, Angle, Grounding, Black: * 2 pole, 3 wire grounding dual power angle plugs with interchangeable blades * Dual power vinyl angle plug - interchangeable blades * 250 Volt * 60 Hz AC Grounding * Molded of tough, black vinyl * Heavily plated steel cable clamp concealed in plug-protected from wear prevents catching on equipment or clothing * Meets all range, dryer and other heavy duty cord requirements * Color-coded terminal screws accept up to No. 6 stranded conductor * Terminal screws are backed out and staked * 3.484"L x 2.562"W x 1.427"D * 30/50 Amp * Maximum cord diameter -.630 - 1.050" * Interchangeable blades * NEMA (6-30P) (6-50P) * Black height.

NEMA 6-20 240 volt, 20 amp Leviton 620PV 20 Amp, 250 Volt, Plug, Grounding, Yellow: 20 Amp, 250 Volt, NEMA 6-20P, 2P, 3W, Plug, Straight Blade, Commercial Grade, Grounding - Yellow

Extension Cords

The following are some useful extension cords.

NOTE CAREFULLY: When in the store looking at extension cords, read the label carefully and look at the thickness of the wire. For charging an EV, we want at least 10 gauge thickness.

Some of these have a molded plug on one end, and bare wire at the other. That makes them excellent starting points for building adapter cords. It's also possible to buy an extension cord, cut off the ends, and attach other plugs, to build a custom adapter.

NEMA 14-50 Camco 55195 50 AMP 30' Extension Cord with PowerGrip Handle: This cord is rated for 50 amps, uses 6 gauge wiring, and has NEMA 14-50 connectors on each end. That's an excellent combination that will handle pretty much any current load you can throw at it.

It's primarily sold for the RV/Camping crowd because lots of RV parks have NEMA 14-50 outlets available. Ergo, an electric car owner could carry a portable 5 kilowatt charging station, and with one of these cords, along with suitable adapters, go into any RV park to charge their car.

Conntek RL14305 RV 50-Amp 25-Feet Heavy Duty Extension Cord: is a similar cord from a different manufacturer.

NEMA 14-50 General Electric WX9X35 4-wire Range Cord, 4-foot: 40 Amp, 4 wire, Range power cord This 4 foot cord is rated 40 amps, 125/250 volts, with two 8 gauge wires and two 10 gauge wires. This cord is a useful starting point for building 14-50 adapter cables

PETRA 90-2028 10-Foot 4-Wire Dryer Cord

NEMA 10-50 240 volt 50 amp Coleman Cable 09014 6/2 and 8/1-Gauge SRDT 50-Amp Range Power Supply Cord, 4-Feet, 3-Wire, 125/250V: Coleman Cable 09014 6/2 and 8/1-Gauge SRDT 50-Amp Range Power Supply Cord, 4-Feet, 3-Wire, 125/250V. Right-angle plug allows installation closer to the wall. Has a 3 prong plug. 50-Amp. 4-feet long wire with strain relief bracket to ensure safe installation.

NEMA L14-30 Iron Box # IBX-5805-50M - 30 Amp L14-30 Generator Extension Power Cord - 4-Wire, 30A, 125/250V, UL LISTED: Heavy duty UL listed L14-30 generator extension cord rated for outdoor use. 50 foot length, uses a heavy duty flexible SJOOW jacket. For use with generators that feature an L14-30R receptacle. Cable generally extends another L14-30 power cord plug, or connects to a transfer switch or inlet box with a male L14-30P inlet.

Conntek 20602 50-Foot 10/4 30 Amp 125/250 Volt 4 Prong L14-30 Transfer Switch Cord/Generator Extension Cord: Generator Extension Cord, 3 Pole, 4 Wire Grounding, NEMA L14-30P to NEMA L14-30R Max Power: 7500W, Stays flexible in cold weather, Heat Resistant up to 221F Application:Transfer Switches, Generator,...etc. Approval: Plug, Connector, : UL, C-UL Cable: 50FT STW 10/4 rating:30A 125/250V

NEMA 6-20 extension cord NEMA 6-20 Extension Power Cord - 25 Foot, 20A/250V, 12/3 SJT - Iron Box # IBX-6153-25M This is a simple 25 foot extension cord with molded plugs for NEMA 6-20. It would be a great companion to the AeroVironment TurboCord shown above.

NEMA L14-30 to 3x 120 volt 20 amp outlets Coleman Cable 01912 25-Feet 10/3 Generator Power Cord with L5-30P Plug and 3-Outlets: The Coleman Cable 01912 25-foot 30 Amp 10-gauge Tri-Source (locking male) generator cord plugs into 30 Amp locking outlets on a generator. The Tri-Source female end provides three extra 15 Amp standard outlets, while the vinyl jacket protects against moisture, abrasions, and exposure to sunlight. The cord features one male 5-20P plug with three 5-15 female outlets, is rated for rugged outdoor use, and is engineers specially to work with portable generators.

NEMA 6-50, 240 volt 50 amp Milspec Direct 25-Foot 8-Gauge STW Pro Grip 40A Welding Extension Cord for Portable Welders, Black: Professional quality patented Pro Grip lighted welding extension cords bring power to where you need it. Today's portable welders have power supply cords that are much too short. Rated at 50A-250V (NEMA 6-50), each extension cord features two clear neon lighted ends that allow you to make sure power is flowing through your cord. In addition, the bright neon lit ends illuminate in the dark and visually makes the connects and disconnects easier to do. The specially crafted, high visibility jacket on Pro Grip cords are designed to be Flame Retardant (FT2), Water Resistant (WR), and Cold Weather Resistant (-40F). Patented Pro Grip nylon handles make pulling apart plugs and connectors from each other easier with less effort and stress. Pro Grip handles easily fold away when not in use.

NEMA 6-20, 240 volt 20 amp Stanley 31626 Grounded 250-volt Heavy Duty Appliance Pro Extension Cord, 6-Feet, Gray: This Stanley Appliance Pro heavy duty 6-Foot extension cord will handle most of your appliance needs where the distance to the outlet occurs. It is a 250 volt cord and has a gauge of AWG 12/3 SPT. The Right angle plug will sit flat against the wall. It has a heavy duty vinyl insulation.

NEMA 5-20, 120 volt 20 amp Yellow Jacket 2806 10/3 Heavy-Duty 15-Amp SJTW Contractor Extension Cord with Lighted End, 100-Feet: Yellow Jacket 2806 10/3 Heavy-Duty 15-Amp SJTW Contractor Extension Cord with Lighted End, 100-Feet. Super flexibility in cold and hot weather. Power Lite power indicator lamp glows through the extra heavy, clear molded plug when the cord has power. Three times as abrasion resistant as standard vinyl, making these cords the toughest on the jobsite. Extra heavy, clear molded plugs are rugged, durable and oversized. Meets OSHA specifications, UL Listed. 10 Gauge.


4 conductor 10 gauge Wire Cord, 50 Ft, Rubber Coated, 10 Gauge, 4 Conductor (10/4) 600v SOOW: 50 foot long Rubber SOOW cord is designed for indoor or outdoor applications. 4 conductors can be stripped and installed in many types of power connectors including L14-30, 5-30, 6-30, 7-30, 24-30, 10-30, 11-30, 15-30 or 18-30. Suitable for use with RVs, Generators and Theater lighting.

4 conductor 10 gauge Coleman Cable 09607 10/4 Bulk Wire, 25-Amp 10-Gauge 25-Feet: Coleman Cable 09607 25-Feet Bulk Wire 10-Gauge 4-Cond SJEOOW Seoprene Rated 105-Degree Celsius, 10/4 Flexible and tough jacket. Offers -50-Degree Celsius to 105-Degree Celsius temperature extremes. Seoprene offers excellent abrasion, ozone, sunlight, chemical and oil resistance as well as water and mold resistant non-wicking lightweight polypropylene fillers. Water resistant with high dielectric insulation. Lightweight, long lasting, easy to carry and easy to handle. All components are recyclable and non-hazardous for environmental landfill disposal. Color coded conductors for easy identification. This type of wire has many applications, they include Special uses requiring flexibility and mechanical toughness, high environmental resistance and flame retardance. Push button remote controls. Motor control, stage equipment and lighting. Industrial control and robotic systems. Outdoor applications. Suitable and approved for submersion in water.

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EV Charging, charging stations, extension cords, charging networks, etc

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Electric vehicle charging standards

The following comes from a presentation at PlugIn 2010 - "The Near Future of Charging Panel AC vs. DC, slow vs. fast – the outlook for charging technologies". The presenters were all members of the SAE committees defining EV (automobile) charging standards.

SAE standards have defined six models of electric vehicle charging. Many have been thinking "Level 1" is regular US household outlets, "Level 2" is the EVSE equipment being deployed for cars, and that "Level 3" is the DC Fast Charge system. The panel presentation was meant to get us straight on what the SAE committee's have been discussing to organize the charging system.


AC Charging DC Charging
AC Level 1 120 V AC Single phase; max 16 amps; max 1.9 kw DC Level 1 200-450 V DC; Current <= 80 amps; power <= 19.2 kw
AC Level 2 240 V AC Single phase; max 80 amps; max 19.2 kw DC Level 2 200-450 V DC; max 200 amps; max 90 kw
AC Level 3 Not defined yet but they might do so, might cover AC three phase DC Level 3 TBD, may cover 200-600 V DC; may cover up to 400 amps; may cover up to 240 kw

Essentially "Level 3" doesn't exist yet and the charging standard everybody has been thinking of as "Level 3" is really either "DC Level 1" or "DC Level 2".

There are unfortunately several kinds of connectors being used:


The AC Level 1 connector we all use in our homes isn't shown. The top connector is the J1772 connector that all the automakers have agreed on. The bottom one is a proposal for DC Level 2 which combines the J1772 connector with a couple extra pins for DC charging.

The connectors defined for Europe are different from the ones defined in the US and Japan. The signals are all the same on the connectors, just the connector shapes are different. Also Japan has defined a DC Fast Charge system, CHAdeMO, which is popular in Japan but the SAE committee is apparently reluctant to adopt.


IEC 62192-2 Type 1 is approximately the same as the J1772 connector. However IEC 62192-2 Type 2 is not.

The pinouts of some connectors under discussion are as follows.


charging ev with solar alternator battery dc to ac convertor

comments needed pro and con . im trying this , i have small dc motor which 3 15 watt solar panels in sunlight spin motor just fine direct , running to wired alternator via belt wire to 12 volt battery then to dc to ac convertor which could handle my 10 small 12 volt chargers 4 amps ..???????????? trying here , perhaps reaching on this ,,,, lonnie

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