NEMA 14-50 outlets or receptacles have been popular for EV charging for many years. They are convenient, affordable, and have an increased charging speed. But you need to use the right kind and size of wire to install these outlets.
A NEMA 14-50 outlet will use a 6 to 8-gauge copper wire for wiring the EV charger. Though copper would be the best choice, you may use a 6-gauge aluminum too. Ensure the distance is short, or the resistance will increase, leading to overheating and fire.
Improper wiring of the NEMA 14-50 can lead to grave situations like a fire. Read this article till the end to know the right kind of wire for the outlet and how to wire it correctly so that the outlet’s requirements are met.
Understanding NEMA 14-50 electrical standards
NEMA 14-50 outlets are popular for EV (all-electric vehicle) charging due to their convenience, low installation costs, and high charging speed in the standard 120V connections.
NEMA 14-50 outlets are 240V sockets rated for the 50 amp circuit breakers.
It is needed for house EV charging and is commonly found in RV parks and houses for dryer outlets and high-powered devices.
Electric vehicles like cars can charge up fully within 6 hours if they receive the right level of 2 EV chargers.
Most phone chargers have NEMA 14-50 plugs which can be directly plugged into the NEMA 14-50 outlet without any extra hardwired installation.
Such plugs are used for heavy-duty appliances like stoves and dryers.
For safety purposes, follow the 80% rule and load only 40% of the outlet’s capacity.
Though NEMA 14-50 charging is famous, hardwired wall chargers or EVSEs give you a better experience.
With fast charging abilities, hardwired chargers are reliable.
The electrical codes have recently demanded GFCI protection for the NEMA 14-50 outlets.
These outlets can wear and tear from EV charging and nuisance tripping (sudden shutdown of the circuit that stops the charging).
The NEMA 14-50 outlets are used for plunged and plugged appliances infrequently.
If you plug and unplug the outlet frequently, it will become loose and wear out faster.
Also read: Wire Size For 50 AMP Service
Recommended gauge wire for a NEMA 14-50 outlet
NEMA 14-50 wiring requires a specific wire for the 50 amp 240V circuits.
The wiring is generally used for dryer outlets, RVs, and other high-powered appliances.
If you use a NEMA 14-50 outlet, you need a 6 to 8-gauge copper wire for wiring.
You may also use a 10-gauge and a 4-gauge copper wire.
The 10-gauge wire will allow you to connect the outlet to the main supply panel, and the 4-gauge wire will connect the outlet to the other end of the circuit at the breaker.
The common type of 50 amp EV charger is a 240V Level 2 or NEMA 14/50 outlet.
According to NEC (National Electric Code) and local codes, you need an 8-gauge wire to power the 240V volt charger.
The size is enough to carry enough current without overheating issues, high resistance, and voltage drop.
Most experts recommend using an 8-gauge copper wire.
Some people suggest using a 6 AWG wire over an 8 AWG wire.
It is because an 8 AWG wire will handle the breaker capacity but might not be able to meet the NEC 80% rule.
So, you can use a 6 AWG wire.
Since the wire will be thicker than 8 AWG, it would provide extra protection.
Since aluminum wires are not strong like copper, are not corrosive-resistant, and have resistance issues, experts recommend avoiding them.
However, if you still want to use it, go for a 4 AWG or a 6 AWG aluminum wire.
The importance of selecting the appropriate wire type for NEMA 14-50 outlets
Using the right size and type of wire is very important for NEMA 14-50.
The wire must be thick and of good quality to handle the breaker load, carry the current safely for longer distances (if needed), and not overheat.
Thicker wire means less resistance and no overheating.
Besides, copper wire is better than aluminum wire in handling the current.
If you have longer distances, you must use copper wires as they are good conductors, are corrosive-resistant, and can carry loads of electricity safely without overheating.
Aluminum wires are fine for shorter distances.
But you need to buy twice the size of the copper wire to match copper’s ability.
Using aluminum for longer distances can lead to overheating and fire.
Copper is only costly if you run your wires for longer distances.
It would be best to use copper wires instead of aluminum.
If you use the wire in a conduit, use a 6 or 8 AWG THHN wire for dry locations or a THWN wire for wet locations.
Many electricians will use 6/3 NM-B copper wires for extra safety.
If you use Romex, it should be sized for 140°F.
The role of wire insulation in NEMA 14-50 outlets
Wire insulation is very important for the NEMA 14-50 outlets.
Insulated wires can provide various benefits. Here are some common roles of wire insulation in NEMA 14-50 outlets:
- Wire insulation will protect the wires from physical damage and keep the wires from contacting the wrong materials, electrical shocks, short circuits, and fire in the NEMA 14-50 outlet.
- Wires are made up of metals that can corrode over time. The insulation will protect them from corrosion and increase their lifespan.
- Electricity can leak if the energy transfers to the framework and other wires. The insulation will protect the wires from touching each other, the framework, and the grounding components of the NEMA outlet and keep it safe.
- Insulation gives you different color coding to identify the wires and their sizes.
The ground wires in the NEMA outlet do not carry any current unless there is a short circuit.
During such a situation, the extra current takes the ground route to flow and saves you from electrocution.
Since the grounding does not carry any current, you can keep it bare.
It should be inside a metal box.
The NEMA receptacle will pick up the grounding via a hard-flush bare-metal face contact between the outlet yoke and the metal box.
Bare ground wires are fine everywhere except for moisture-prone areas.
But, it is safer to use an insulated wire, be it copper or aluminum.
The proper installation of wire for NEMA 14-50 outlets
Before the work starts, the electrician should ensure that you have the electrical capacity of a 2-pole or 240V circuit breaker on the main service panel.
The experts will calculate the load to confirm the capacity of your NEMA outlet.
Then you need to have a proper location to install the outlet.
Ensure that the location you choose for installing the outlet contains enough space and cable length to attach your EV and that no obstruction disturbs the wiring.
Leave enough bumper to align the outlet with the EV charging station according to the manufacturer’s suggestions.
Check the make and model of your main panel to purchase the right breaker.
If you have a rare or old breaker panel, consult your local electrical supplier for the right breaker.
Now, let’s skip to the steps:
- Take the cover off the panel and disconnect the main power.
- Cut off the electrical box hole where the outlet will be installed.
- Cut the wire according to the project’s requirement, based on the panel and EV’s location. Remember that long distances will increase your eventual bill.
- Now, install the conduit run and pull the wire through the conduit.
- Pull the wire through the electrical box at the EV charging station and the panel where the breaker will be located.
- To ensure that the process follows the NEC guidelines, connect the neutral and hot wires in the right locations. Connect the outlet’s ground wire with the circuit’s ground wire.
- Keep the outlet in an electrical box and secure it with two screws. Attach the wires to their respective screws and test the outlet with a voltage tester.
- If you have a hardwired EV charging, you will mount it on the wall with an extra flexible conduit and wires.
- These wires will meet and get connected to the electrical panel’s wires.
- Install a GFCI breaker on the NEMA 14-50 outlet for safety purposes to prevent injuries and fires. Though you may face tripping issues, GFCI will save you and your house from electrical accidents.
- After you have finished the wiring, turn on the main power and check the outlet’s functionality.
Hire an electrician if you hesitate to wire the outlet yourself.
It will save time and effort and avoid silly mistakes and expensive damages.
Some old electrical ranges may have 2-wire cables (2 hot and ground) on the 50 amp circuit breakers.
The EVSEs don’t need the neutral, but your NEMA outlet must have a neutral wire connected according to the code.
You will need the neutral if you plug a NEMA 14-50 12-/240V plug into something else.
The neutral wire will act as a return path for the current that flows from the hot wires to the device connected to the outlet.
Without the neutral wire, the device will face issues while drawing power from the outlet.
Maintenance and safety tips for NEMA 14-50 installations
While wiring the NEMA outlet 14-50, you must follow a few safety measures.
Since it is electrical work, you should not do it if you don’t have experience.
If you have done it before, follow the following maintenance and safety tips:
- You can install a NEMA 14-50 outlet, but you must consult your local building codes and regulations.
- You should have permission for the installation and stick to the instructions from the manufacturer or a licensed electrician.
- Purchase the right size and kind of wire for the outlet and ensure that the wire connections are secure and the wiring is made according to the local codes.
- Turn off the power before you start working with the outlet.
- Once you have finished it, secure the wire connections and double-check every connection for safety.
- Wear protective gear before working and avoid working in wet areas.
- Use a voltage tester to check the readings before and after working.
- Use thick copper wires to avoid electrical shocks. If you have bought aluminum wires, you should use them for shorter distances.
If you need a NEMA 14-50 outlet installed in your house, you should contact an electrician for the installation.
Though the steps shared in the article will help you, it is still better to hire an experienced electrician so that he can do all the wiring connections properly according to the NEC and local codes without mistakes.
The right size of wire is a 6 or 8 AWG copper wire.
You can use either aluminum or copper, but copper is preferred the most due to its impressive features like better conductivity, corrosive-resistant, thicker wires, etc.
Since copper is expensive, many prefer aluminum.
If you are using aluminum, use it for shorter distances.
A 6 or 8 AWG copper won’t be too costly unless you use wires for longer distances.
Use a THHN wire for dry locations and THWN wires for wet locations.
How much does it cost to install a NEMA 14-50 outlet?
The installation prices for wiring a NEMA 14-50 outlet range between $500 and $2,500. It may vary based on the work and your region.
Can I use a 60 amp breaker for NEMA 14-50 outlets?
Using a 60 amp breaker for NEMA 14-50 outlets is not recommended. These outlets are generally rated for 50 amp breakers and should be used for the same.
Reference: NEMA Wikipedia