What are the Different Power Cord Types?

Ready to buy a new electric range, electric dryer, or dishwasher? Did you know that most electric ranges and electric dryers no longer come with a power cord? This means you need to buy one BEFORE the installation crew arrives. And trust me—and I speak from personal experience—unless you can correctly select between the various appliance power cord types, your installation will hit a major roadblock.

Why no power cord? There are several reasons.

• Depending on when a home was built, the outlets may be different. So, no one wants to have a pre-attached power cord that won't work with a home's outlets. Plus, it's unsafe to use an adapter in 220/240-volt applications.
• Today's delivery crews rarely have electricians. Therefore, they cannot direct-wire your appliance into any bare wires poking out of a wall or change out an outlet to a different kind.
• Simply plugging a cord into a wall outlet is a whole lot faster and less risky. It also speeds up installation time and increases the number of deliveries a crew can make in a day.

So, your very first step, BEFORE you go to the store, is to carefully wiggle out the appliance you are replacing to see what kind of outlet is there. Then:

1. Take a photo of the outlet and of the plug end of the current cord so you have a reference
2. Measure the length of the current cord
3. If it is bare wires, call an electrician and have an outlet installed that's appropriate for the appliance you're buying. Do this BEFORE the appliance delivery guys show up! 

If you are replacing an electric range or dryer with a natural gas one, you will need to have a regular/normal 3-prong wall outlet installed. They run on standard 110/120-volt power rather than 220/240 volts. Dishwashers, like refrigerators, also use standard outlets. 

So, let's look at all the variables that go into power cords:

• Kinds of outlets and plug ends
• Volts
• Amps
• Watts
• Amps and watts in power cords
• Wire gauge
• Classification codes
• Straight or right-angle plug ends

220/240-volt power plug types and outlets

Look at the photos you snapped and compare them against this handy reference guide we've compiled. It shows what the various types of wall outlets look like as well as the actual plug ends, and the illustration art often used on packaging.

Courtesy Certified Appliance Accessories® 

So, when you settle on an appliance, ask at the store what amp capacity the power cord should have. Dryer cords tend to be 30 amps while range cords are 40 or 50 amps. Smaller electrical power supply cords usually come in 10-amp/1,250-watt, 13-amp/1,625-watt, and 15-amp/1,875-watt capacities.

Match the existing ends and cord length from your home with the amps of the new appliance, and you'll know which power cord you need to buy. Easy!

If there are only wires poking out, or you have a new home that doesn't yet have an outlet, your electrician will install a 4-wire version for your 220/240 appliance. It is the latest, code-mandated wiring requirement. Homes built before 1996 generally have 3-wire outlets. If you have a 3-wire outlet, don't worry. It's still safe. The difference is that 4 wire adds a separate ground.

I might suggest that if you need an electrical outlet put in behind your dishwasher, have a recessed one installed. Often, there's not a lot of space behind a dishwasher that sits under a countertop, so a recessed outlet can help. It certainly did in my mid-1960s home where cabinet depth is shallower. Make sure the recessed one can accept a right-angle plug as well as a straight plug. This gives you more power cord plug-head options as well as depth-of-appliance options.

What about the watt and amp listings on appliance power cords? And just what is the difference between watts and amps and volts?

Let's start with volts first.

What are volts?

Voltage is electrical pressure. Its unit of measurement is the volt.

Today's homes generally have a nominal voltage of 120 volts. Sometimes it is called 110, 115, 117, or even 125. But for any calculations you might do, work with 120. It's close enough.

Quick220.com explains what happens at the utility company's power pole and then your home:

"Inside the transformer on the utility pole, the power is divided into a split phase system, with each line having a nominal voltage of 120 volts. Nominal voltage is the voltage that the line is designed for; however, in the real-world, the tolerance for voltage fluctuations is −5% to +5%. This leads to an actual voltage range of anywhere from 114V to 126V from your outlet and a voltage range of 228V to 252V for your full-phase appliances."

What are amps?

Amps are the quantity of electrical current being drawn. 

Your circuit breaker box probably has 15-amp, and 20-amp circuits. If it's older, it may even have 10-amp ones. The 20-amp circuits are for higher-power, regular-outlet appliances like the dishwasher and refrigerator. The bundled together ones are for your 220/240-volt appliances.

Beyond amps and volts, there's an important difference between your regular circuits and the 220/240 ones. Each 10-, 15-, or even 20-amp circuit handles multiple wall outlets as well as wired-in ceiling lights, wall sconces, etc. This can lead to overloading a circuit if you're not careful. Each 220/240-volt circuit is dedicated to a single special outlet. Therefore, overloading is not a problem.

So, when it comes to your smaller amp circuits, it is important to know the watts and amps for everything you plug into the wall, so you won't overload it and trip the circuit breaker.

What are watts?

Watts measure the amount of electrical power being drawn.

Confused?

Current (amps) and power (watts) are two different things. Differencebetween.net has this example:

"A device that draws 2 amps from a 12 volts source is consuming 24 watts while a device that draws 2 amps from a 24 volts source is consuming 48 watts…Amps is the unit of current flow, while Watts is the unit for power."

This means that watts, amps, and yes, voltage are all interconnected. If for some reason you need to know the watts but only have amps and volts, or you require the amps but only have watts and volts, you can calculate the missing information.

Since you know what the voltage is—either 120 or 240—an online calculator (https://www.supercircuits.com/resources/tools/volts-watts-amps-converter) can come up with the missing variable. Plug in the two numbers you know and hit Calculate! 

For those of you who wish to do it old school:

Amps x Volts = Watts

Example: 10 amps x 120 volts = 1,200 watts

To calculate amps:  

Watts ÷ Volts = Amps

Example:

100 watts ÷ 120 volts = .8333 amps

If you need a chart that also works with DC power as well as AC Single (homes) or AC 3 Phase (large businesses and manufacturing plants), use this site. You can convert watts to amps or amps to watts. The only other piece of information you need to know for this calculator is that the power factor for homes is 1.

Amps and watts in power cords

The names of each of our Certified Appliance Accessories dryer and range cords include the amps. For example, if you take a look at our range cords, you'll not only see the reference to 3 wire or 4 wire, but also the amps. 

The same holds true for the dryer cords.

For the appliance power supply and extension cords that plug into standard wall outlets, you'll see amps in the item name and watts down in the specification bullets. Those two numbers will help you figure out just how much the cord can handle.

For example, the 10-amp cords can handle up to 1,250 watts. The 13-amp ones handle up to 1,625 watts, and the 15-amp ones handle up to 1,875 watts. Those numbers are based on 125 volts as a precaution.

Certified dishwasher installation kits include our 15-amp power cords. Those cords can also be purchased separately.

And if for some reason, you need to extend the reach of an existing power cord, or simply want to make a hidden outlet more accessible, Certified has 15-amp appliance extension cords. Please note that extension cords, no matter how beefy, should not be used as a permanent installation.

Wire gauge

Gauge, often written as AWG, is how thick the cable is. The lower the number, the thicker the wire and the more current capacity/electrical power/amps it can carry with less resistance or loss.

Also, if the cable run is too long, electrical voltage loss can happen—not a good thing for the devices on the other end. So, long extension cords will have a lower capacity than shorter ones made from the same gauge of wire.

The Spruce puts it this way:

"For example, an 18 AWG cord may only be rated for 5 to 7 amperes (amps) of load at a length of up to 25 feet. To get the same load rating with a 50-foot cord, the cord must have larger, 16 AWG wire. Because of the voltage drop, it's best to use the shortest extension cord possible for the job at hand."

Certified Appliance Accessory cords follow industry standards when it comes to which gauge cords to use. 40-amp range cords use 8-gauge and 10-gauge wiring bundled together. 50-amp ones use 6 gauge and 8 gauge. Dryer cords use 10 gauge bundled together.

Certified 10-amp power supply cords are 18 gauge. 13-amp ones are 16 gauge. And 15-amp cords are 14 gauge.

Wire gauge is not something you necessarily have a choice between when it comes to range, dryer, and appliance power cords, but it's good to know, just in case.

Classification codes: Deciphering those mysterious letters found on cords

Let's decode those groups of letters printed on or deeply stamped into power cord jackets, or at least referenced in illustration art or specs. Knowing the code (or string of code letters) can help you choose the right cord for your needs.

The explanation below comes from Home Depot:

• An "S" cord is flexible and designed for general use.
• A "W" cord is rated for outdoor use.
• A "J" cord has a standard 300-volt insulation. If there is no J in the designation, the cord has thicker, 600-volt insulation, designed for heavier use.
• A "P" cord has a parallel wire construction, used in air conditioner cords and household extension cords.
• A "T" cord jacket is made from vinyl thermoplastic.
• An "E" cord jacket is made from thermoplastic elastomer rubber (TPE).
• An "O" cord is oil resistant.
• An "FT2" cord is flame retardant.
• A "CL2S" wire is designed for in-wall construction.
• An "SRDT" wire is heavy duty and good for high amperage products.
• An "HPN" the cord’s performance won’t be affected by the high temperatures associated with appliances. 

Certified Appliance Accessory range and dryer cords are classified SRDT. The 10-amp power supply cord is SJTW. The 13 and 15-amp cords (both power supply and extension) are SPT-3. 

As you've guessed from the SPT-3, there are further SPT designations. Per coilcablespecialist.com:

SPT-1—Parallel jacketed thermoplastic cable, 300V. With or without third conductor for grounding. (PVC)

SPT-2—Same as SPT-1 but heavier construction. (PVC)

SPT-3—Same as SPT-2 but heavier construction. (PVC)

So, rest assured, our Certified power supply and extension cords are as heavy-duty as they come.

Why are some power cord plug ends straight and some are right-angled? Does it make a difference?

Most 220/240-volt and many 110/120-volt appliance cords use a right-angle plug head.

There are advantages to using a right angle power cord when it comes appliances. The plug head itself sits closer to the wall so the appliance can be closer to the wall too. Plus, the power cord itself drapes closer to the wall. This puts less strain on the plug head connection and there's the bonus of the cord being harder to unplug by accident.

The Certified dishwasher power cords are available with either straight or right-angle ends. This provides a choice for installers so they can best handle the jobsite requirements.

Power cord types explained

Hopefully you now have a better idea of what to look for when it comes to appliance power cords. And if you need to buy one, be sure to check out the cords from Certified Appliance Accessories. 

You can purchase them online at Lowe's, Walmart, Amazon, and other ecommerce sites. 

Happy power cord hunting!

Disclaimer: This article is for informational and educational purposes only. Certified Appliance Accessories is not liable or responsible for any damages resulting from or related to your use of this information.