WesBell Electronics
Wire and Cable Blog

Category: Romex

Three Types of Electrical Wire: THHN, UFB, and Romex Wire Revealed

There are many types of electrical wire available for consumers, however, it’s easy to get confused by the different types. The most common types of electrical wire are THHN, Romex, and UFB wire. However, in order to understand which electrical wire will do the best job for a specific project, it’s best to know the capabilities of each kind of wire.

  • THHN Wire

THHN wire is covered with a PVC jacket and nylon coating. This wire is a bare one conductor copper wire and is often used indoors or in conduit. The most popular sizes for THHN wire are 12 and 4/0, though other sizes are available for nonstandard projects. The PVC jacket is one of the cheapest forms of insulation for this type of wire and the nylon coating provides waterproofing and slight lubrication for placing in a conduit. Because of the ‘bare essential’ nature of this wire however, it isn’t recommended for outside use.

  • Romex Wire

Romex wire is made out of two or three THHN wires combined with a grounding bare copper wire. Like the THHN wires, Romex wire can’t be used outside because of its minimal PVC jacket protection. However, these wires come in larger sizes than the thinner THHN wires; 14/2 and 6/3 are used widely as electrical wire, despite the fact that it can’t be used in conduit at all. The primary use for this type of wire is to run more than one conductor at a time through a separate grounding wire.

  • UFB Wire

UFB wire is one of the most popular and versatile brands of wire available, though it’s also the most expensive. It can be used in conduit, outdoors, underground, you name it. Because it deals with tougher terrains than THHN or Romex, UFB wire comes in larger sizes, most commonly 6/3 and 8/3 and is often called ‘underground cable’.

The more jobs that an electrical wire does, the more expensive it is. It’s important to know what the different electrical wires do before committing. Frequently, that added expense can save a lot of costly replacements and time-consuming repairs.


NM-B Electrical Wire Information

NMB Electrical WireNM-B electrical wire is a very popular type of cable used throughout homes and buildings to bring power from the electrical box to the lights, outlets and appliances. The 14, 12 and 10 AWG circuit sizes are the most common household electrical cables because of the amount of AMPS they offer. Different manufacturers engineer different types of NM-B cable but all types must still meet a certain standard noted in the NEC or National Electric Code.

NM-B Circuit Sizes

NM-B electrical wire circuit sizes are the smallest 3 sizes which are 14, 12 and 10 AWG. The 14 AWG NM-B cables have a white outer jacket, the 12 AWG cables have a yellow jacket and the 10 AWG cables have an orange jacket to set them apart. These three cables run from the electrical box in your home, through the walls to your lights, outlets and appliance outlets. All you will see is an outlet or a light assembly instead of any wiring. Once you pull off the outlet casing you will see the wiring behind it.

Southwire Brand Romex® NM-B Cable

Romex® is a brand name of NM-B cable that Southwire manufactures. It’s similar to buying the brand name of Kleenex® instead of another brand of tissues. It needs to be manufactured to the same specifications per the NEC code but it can be enhanced. Therefore, buying another brand should suffice but buying a premium brand can sometimes lengthen the life of your electrical cable.

Larger Sizes of NM-B Electrical Wire

Larger sizes of NM-B cable refer to 8 AWG through 2 AWG with two or three possible conductors. The bare copper ground wire is additional and not noted when you see: NM-B 6/3. A 6/3 electrical wire will have 3 insulated conductors that are color coded and an additional ground wire without insulation. These cables are more often used to hook up an indoor hot tub, a large appliance or indoor shop equipment. They aren’t flexible at all and cannot be used outdoors either. Therefore, the entire connection must remain indoors if you plan on using NM-B cable or Romex® cable.

Knowledge is power in nearly every industry. Having the knowledge of a subject will allow you to buy and sell in an educated fashion. For instance, understanding that NM-B cables are priced based on the value of copper as a commodity, will allow a savvy buyer to purchase their copper cables at the correct time rather than just replacing a cable when the time comes up.

Written by: Chris Bell

Romex 14 2 Cable – Your Home Wiring Needs

Romex® (rome-eks) has become the standard brand name in sheathed, insulated wires. Electrical systems in homes and businesses are mostly wired using Romex®. It is made up of two or more insulated wires with a flexible plastic sheath. Romex® cable can be run through walls, attics, under floors and others.

Romex® wire comes in many different sizes. Romex® 14/2 Cable is used as branch circuits for switches, outlets and other loads in residential wiring. It can also be used in concealed or exposed work in normal dry locations. You may run it in air voids of masonry block or in tile walls but should not be subjected to too much moisture. This cable is not for direct burial on the ground.

Romex® cable is easier to run through holes in studs due to its flexible sheath compared to metallic sheath and it is also cheaper. That is why it is labeled NMC which means non-metallic cable. NM is the sheathing used to distinguish it from metallic (BX or AC) sheathed cable. A rating of 14/2 pertains to the wire gauge and how many wires are inside the cable. 14 is the wire gauge and 2 means there are 2 wires in the cable. The lower the gauge is, the larger is the wire.

Romex® 14/2 Cable comes in white color jacket only because it falls under the #14 wire range. Other gauge sizes come in different jacket colors. This type of Romex® cable is an indoor residential electrical wire with solid bare copper strands. It weighs 57 lbs per 1000 feet and has 15 amps. It can resists temperatures up to 90°C and a maximum of 600 volts.

If you are thinking of using Romex® wires for your household wiring system, you need to make sure that you know the correct size to be used. The length and amount of amps you want are important to know the correct awg size. When you talk to your electrician or contractor, this information is needed so they can give you accurate information of what type of cable you should use. Take note that this cable is for indoor use only. If you need to run a cable outdoors, then you need a different type of cable built for outdoor use.

For a cable that pulls faster and strips easier, Romex® 14/2 Cable has these qualities. It is also tear resistant and has reduced burn-thru. It comes in 2 and 3 conductors and has awg sizes of 14, 12 and 10. Wesbell Electronics offer larger Romex cables by the foot in awg of 8, 6, 4 and 2. Since you need specific lengths and does not want to put your excess to waste, Wesbell Electronics allows purchasing of larger Romex® wires and UFB cables in any length that you desire.

For any specific requirements that you need for your cables and wires, please call Wesbell Electronics customer service and they will be glad to answer your inquiries and assist you in your wiring needs.

WesBell Electronics Inc
(800) 334-8400

Why Romex© Can’t be Used Outdoors

Romex© is a type or electrical wire used indoors only for a few reasons. We get this question a lot since it has THHN THWN wires inside it that are allowed to be used outdoors.

Yes, THHN THWN wire can be used outdoors but not directly underground. Romex©, however has a bare copper ground wire inside the cable that is NOT fully protected by the PVC jacket covering all of the conductors. So when Romex© wire is used outdoors and gets wet with water, gas, oil or any type of solvent it could penetrate the jacket and ruin the connection by getting in contact with the bare copper ground wire.

What should you use instead?

MC cable can be used indoors and outdoors because the ground wire is an insulated THHN THWN wire as well. The common use for MC cable is indoors because it can be used without conduit for a much easier installation. However, even if the metal clad jacket doesn’t fully protect the THHN THWN wires they already have the approvals alone to withstand outdoor environments. Copper and Aluminum MC cable can also be used in conduit.

Why not just run THHN THWN wires individually?

You can. Depending on the current copper prices we’ll sometimes push our customers in that direction because the cost of all 4 electrical wires are cheaper than the cable. However, sometimes the cable is cheaper as well. There’s also the added labor involved in pushing each individual wire through conduit or tying all four together to push them through as a group.

We have a highly trained staff here at WesBell Electronics and are here to help you. We’ll give you the cheaper option before you ask and help you find the correct cable by the installation it’s going in. If you have questions please ask and we’ll gladly help you through the process and explain what we’re saying to help you understand.

Toll Free – (800) 334-8400

Save Your Romex Wire!

I’m sure most electrical contractors know about the fluctuation of copper pricing in the last few years which means they understand they need to keep all excess copper wire to scrap later on. Copper has been as low as .86 per pound and as high as 4.10 per pound so the stock market slogan “buy low, sell high” comes into play here.

Sometimes electrical contractors tell the homeowner to find the wire and cable they need on their own to save a few dollars on the cost of the installation. However, they may not know that they can sell the unused wire to a scrap yard for cash. You can call them and ask what the current copper price is and they’ll give you a little bit less than what you might see on the NYSE. Then they melt down the copper and sell it to copper wire manufacturers to make a profit.

Currently copper is about 3.30 per pound so if you have 50 ft of Romex 6/3 then you can probably get about $55.00. Romex 6 awg 3 conductor weighs about .357/foot and you can get about 3.00 per pound right now. So it adds up quicker than you think.

Be careful of those copper thieves out there though! We have another blog post with a video showing all the people stealing copper wire to scrap it for cash. They’re stealing it from live connections (some are getting electrocuted) and anywhere else they can find it because it’s worth so much right now and it’s so easy to scrap for cash.

Romex Cable Pricing

You might wonder how you can call 5 different wire and cable distributors and get a range of pricing for the same product. You’re expecting to get better pricing than Home Depot and Lowes right? Well sometimes that’s the case and sometimes it’s not for multiple reasons.

1. Copper

Copper is a volatile commodity traded on the stock market which changes the prices of electrical wire and cable drastically. Electronic cable and portable cord products have more engineering, jacket and materials in them to affect the price. Electrical wire and cable is mostly made with copper and a small amount of insulation to keep costs down as much as possible.

Copper can go up or down over 10% each day depending on how much play it gets and the supply and demand of the actual product. Normally when contractors call for pricing on large amounts it will come straight from the manufacturer because stocking that much copper can be fatal.

2. Time of Purchase

With copper going up and down daily it’s just as hard to time the purchase of inventory as it is the next big stock purchase. Your hope is to buy at the bottom and sell at the top but that scenario is usually unlikely. So assume you buy 50,000 feet of Romex 14/2 for your inventory at .15/ft and copper drops 10% over the next week. If a customer calls to purchase 10,000 feet you will mark up your .15/ft while other distributors who don’t have stock will mark up a price of .135/ft (10% less). Ideally if that distributor only wants to make 10% on the order they could sell it at your current cost.

On the flip side of that scenario the inventory could work in your advantage. Assume you bought the Romex 14/2 at .15/ft and copper went up 10%. You now have the upper hand to possibly make a little more than you planned because distributors without inventory must buy at a current price of .167/ft (10% higher).

3. Clout/Relationship with Manufacturer

Most people and businesses understand quantity breaks where 1 TV will cost $900 and 10 of the same TV’s might cost $850 each. The same works in the wire and cable industry but relationships are a big part as well because the manufacturers have competition too. They like to see that you trust in their product, price and customer service so much that you don’t call anyone else. That’s worth a better price to them and you can work together at creating new business and opportunities.

Those 3 points are fairly specific to the wire and cable industry but are also standard in the name of business itself. You shouldn’t take advantage of a good customer by saying; “They always buy from us anyways”. That’s a very poor look at customer service and treating you current customers worse than potential new customers is not a good idea.

Some companies offer deals only available for new customers! That’s an outrage! Treat your current customers better than your new customers because they’ve been giving you business for years and deserve that treatment. How would you feel if you’ve been buying TV’s for years from the same company at $850 each and then they offer the same TV to new customers only at $800 each? Probably like you’re worth nothing to them? Then don’t use this technique on your customers or they may feel the same way.

Using Romex® Electrical Wire in Conduit

If you’re looking for a cable for indoor conduit or duct that is ideal for indoor use and its ease of installation, than consider Romex® cable.

If your cable requires outside use, a certain insulation and jacket encased wire is necessary to protect it from the environmental conditions it will face. Generally, Romex® cable cannot be used in conduit or even used outdoors (due to the ground wire in the cable). However, Romex® that does not have a bare ground wire may be used both outdoors and in conduit.

THHN wires can be used outdoors, so without the bare ground wire dual rated THHN THWN wires inside the Romex® jacket can be used indoors and outdoors. Use caution however as the jacket for this product is thin and may not provide the necessary protection.

If however, you require the ground wire for an outdoor application, you may want to consider MC cable or UF-B cable. MC cable has a THHN ground wire and the UF-B cable has a protective jacket to resist environmental conditions.

If you have additional questions about these cables or any of your wire, cable or heat shrink tubing needs, please contact WesBell Electronics at 800-334-8400.