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Published on 3/7/2007

AWC eUpdate Newsletter March 2007

Voltage Drop Guide

Copper Prices

Let's face it; you've probably never heard of the term Voltage Drop, and if you have, it isn't something that crosses your mind every day. Did you realize that by taking just a few short minutes to do this calculation you could increase the operating life of your equipment? Misconceptions are common when it comes to voltage drop, but learning why it's important and how to calculate it could end up saving you time, money and heartache in the long run.

The term "voltage drop" essentially refers to the reduction of voltage in any electrical circuit. It is the electrical potential of the circuit lessening across a component or conductor. A significant drop in voltage could be the negative result of an incorrect conductor size in a cable.

When in the process of choosing a cable for a specific circuit, a common standard used to determine the cable type and size often is ampacity. Ampacity refers to the greatest current a conductor can carry. In some situations, opting for a larger conductor size than required is essential. Usually these instances occur with long runs of electrical wire when, because of the excessive voltage drop, a larger conductor size is necessary to carry the existing current. Voltage drop thus becomes a major concern when installing long lengths of wire.

In long runs, the total voltage lost between the power supply and the device being powered can be considerable. In short circuits, voltage drop will not be a major consideration because the total voltage lost is not substantial. For example, with residential buildings wired circuits are typically not long enough for voltage drop to be a factor of consequence.

Some people are under the impression that the NEC (National Electric Code) requires you to size conductors to accommodate voltage drop. Although the NEC recommends that the maximum on branch circuit should not exceed 3%, this is only a recommendation and is not mandatory. Having a voltage drop higher than 3% is not necessarily a safety concern, but rather a performance concern.

In the appropriate circumstances, finding out voltage drop is a wise first step because low voltage has many negative consequences, such as wasted energy in the wiring system. Wasted power is commonly followed by poor operation of electrical equipment, among other problems. Determining voltage drop is essential, since not doing so could be detrimental to the life of your equipment.

Because many factors need to be computed, figuring out a precise voltage drop for a circuit is often a long and difficult process. There is a shorter, although less exact, method using charts provided by American Insulated Corp. In order to calculate the voltage drop, multiply the length of one conductor by the current and by the figure in the table for conductor size, circuit type, and power factor. Then, divide by 1,000,000. The number produced is the estimated voltage drop. If the projection is larger than 3%, you should consider selecting a larger conductor size.

Even though the NEC does not mandate a maximum voltage drop allowed in a branch circuit, voltage drop between input and output connections can be important. Keeping voltage drop to a minimum proves to be a wise, cost-effective resolve. Sizing your circuit conductors properly will limit voltage drop, helping cut voltage waste and ensure the competent operation of your equipment.

For more information, please see "Voltage Drop," and charts by American Insulated Wire Company.

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National Electrical Wire Processing Technology Expo

National Electrical Wire Processing Technology Expo Website

Allied Wire & Cable will be exhibiting at the National Electrical Wire Processing Technology Expo in Milwaukee, WI. The 2007 Expo will take place Wednesday, May 23rd from 9am - 4pm and Thursday, May 24th from 9am - 3pm. The event will be held at the Midwest Airlines Center, a state-of-the-art facility located in Milwaukee.

The National Electrical Wire Processing Technology Expo is an annual exhibition dedicated to electrical wire processing and related industries. Over 100 suppliers and service companies in the wire and cable processing industry will be in attendance.

Allied Wire & Cable will be showing at booth #1534, so be sure to visit us at one of the nation's largest dedicated wire processing events.

For more information, the Expo can be reached at 1-800-367-5520



Play Allied Wire & Cable Trivia

Allied Wire Quiz Logo

It's time to play "Allied Wire & Cable Trivia." The first 5 people to correctly match these five members of Allied's staff with their future spouse/wedding date will receive an Allied Prize Pack overflowing with goodies.

Answers should be emailed to trivia@awcwire.com or faxed to 484-928-6700. Please include your full name, company name, and shipping address along with your answers. Good luck!






Couple 1
Couple 1: April 5, 2007
Couple 2
Couple 2: April 21, 2007
Couple 3
Couple 3: June 2, 2007
Couple 4
Couple 4: Sept. 29 2007
Couple 5
Couple 5: June 7, 2008


And we'd like to send out congratulations to those couples not pictured: Debby Lupo (WI account representative) who tied the knot in January, Reese Thompson (Accounting) and Rich Roselli (Sales) who will be getting married in July, and Rebecca Hughes (WI sales assistant) who will be getting married in August.

Look for the answers in next month's newsletter!

Click here for the answers from February's Trivia Question