WesBell Electronics
Wire and Cable Blog



Posts tagged: underground electrical cable

Copper Electrical Cable Differences

Copper electrical cable is very expensive, but the real differences in price actually comes down to the insulation type more than the copper. Copper is the conductor of electricity in all copper electrical cables and the price of copper changes everyday. However, Romex 6/3® has the same amount of copper as UFB 6/3, so why is the price different?

A 6 awg wire is a 6 awg wire whether it’s in a Romex NMB® jacket or a tough underground PVC jacket. That means each 6 awg wire would be the same price if they were both stripped of all insulation. A UFB underground insulation was manufactured to be used without conduit. So the jacket needed extra protection in order to last as long as an electrical cable in conduit.

In order of the amount of protection Romex® comes first, MC cable second and UFB cable third for electrical cables. Even though each of these cables have different levels of protection they all still have THHN THWN as the wire conductor insulation, so what changes the fact that some have more restrictions?

Romex® cable has a bare copper uninsulated ground wire, but lacks a strong enough jacket to protect it outdoors or in conduit. Moisture, gas, solvents and other fluids can puncture the jacket and hit the bare ground wire leaving it only available for wiring indoors.

MC cable is manufactured with all THHN wires and a THHN insulated green ground wire. That allows MC electrical cables to be used outdoors and in conduit because it resists all water, moisture oils and gases without an uninsulated ground wire in the way.

UFB cable is manufactured as an underground electrical cable which is also known as direct burial in the wire and cable industry. It still has an uninsulateed ground wire but the PVC jacket is engineered tough enough to protect all of the wires even when used directly underground.

In order to find the cheapest cable possible you’ll want to first speak to an electrician to let you know the awg size of the cable you need. This will prevent you from getting a size too big and paying more money than you need to. The second thing you want to do is make sure you’re not getting too much insulation that you may not need. Getting UFB cable when you’re using conduit anyways is a waste of money. You should get MC cable which is cheaper and manufactured for use in conduit.

We offer exact cut lengths on all of our electrical cables and THHN wire because in the contractors, engineers and installers like to have the exact length they need to avoid waste of small lengths at the end of each spool. We also offer free shipping on orders over $250 so that you don’t have to negociate deals with trucking companies to get spool of wire or cable.

Please call us if you need any type of wire, cable or heat shrink tubing as we’ve been a stocking distributor for over 25 years.

WesBell Electronics Inc
(800) 334-8400

Electrical Wire Questions and Answers

We get a lot of phone calls and emails with questions about many different types of electrical wire and cable. Since some of them are repeated we’re going to put them on our website so that people can find the answer before they need to make a phone call.

What type of electrical cable do I use to run electricity to my barn or garage?

If it’s above ground or in conduit you can use SER (Service Entrance Cable). Talk to an electrician first to check the gauge of the cable you’ll need. The electrician will do a calculation based on the length of the cable, the amount of amps you need and the voltage.

If you want to run the cable directly underground then you need to use UFB cable or Tray cable. UFB cable is an underground feeder that has added protection to be used underground. If you need something bigger than 6 awg then you’ll need to use tray cable which can also be used directly underground. Tray cable gets as big as 750 mcm with 4 conductors plus a ground wire.

Can I use Romex wire if it’s only going to be outdoors for 10 feet?

No matter how long I work for a wire and cable company I know this question will continue to come up. Romex can NOT be used outdoors because the jacket insulation isn’t manufactured with enough protection to resist any moisture, gas, oil or solvents. Anything that penetrates the jacket could hit the bare copper ground wire and short the connection.

Can I use THHN as dog fence wire?

Only if you keep the wire above ground. Usually dog fence wire is buried in the ground so you’ll need a wire that has enough protection to be used directly underground. THHN wire is used indoors, outdoors and in conduit only. The manufacturer states that THHN can not be used underground so that’s the message we pass along.

What type of wire do I use if I need high temperature?

Standard PVC hook up wire is rated for 105°C with a few different voltage ratings available. If you need higher temperature then you should use PTFE wire which is rated up to 200C. It’s silver plated copper with a PTFE insulation and it’s getting more expensive by the minute. Copper is rising, silver is rising and PTFE compound is also rising to give PTFE wire 3 possible inceases each day.

Please email or call us with any questions you might have about electrical wire and cable.

WesBell Electronics Inc
(800) 334-8400

Tray Cable is the Newest Electrical Wire Addition

The newest product addition to WesBell has been tray cable because of the amount of uses this type of electrical wire has. It’s universal in a sense because it can be used just about anywhere without an oversized jacket.

THHN / PVC Tray Cable is the standard type with THHN wires and a bare copper ground wire. Each wire is black with a number code of 1 through 4. The tough outer PVC jacket has the approvals for direct burial in the earth.

Another type of underground cable available in this field is UFB Cable. The difference with UFB wire is that it’s color coded and flat rather than round. It’s the common step up in smaller applications up to 6 awg from Romex and MC cable. Romex can be used indoors and MC cable can be used outdoors but not directly underground.

However, if you need a bigger gauge underground cable then tray cable sounds like a good fit for your application. It’s 600 volts type TC-ER tray cable and comes in copper conductors only.

There are many types of electrical wire types even though most of them come with copper conductors. Each insulation type is a step up from the next to offer a variety of pricing. Obviously and indoor only cable will be cheaper than one that can be buried directly in the ground because of the approvals and tests it needs to go through. So be sure to tell your sales person exactly what you’re using your electrical cable for in order to pay the lowest price possible.