Engineering data for copper and aluminum conductor electrical. Based on nec table 31016 as shown in the nec table 31016 below the temperature rating of the insulation has much to do with how much electrical current the wire is designed to withstand. For voltages up to 2000, it is 14 awg for copper and 12 awg for aluminum or. Allowable conductor ampacities based on ambient temperature of 30. Usually, a general purpose house circuit is designed for 20 amps. All aluminum conductor, bare construction aluminum alloy 50h19 wires, concentrically stranded. The table that lists the allowable ampacities for copper conductors when there is not more than three of them in a raceway or cable is. Usually the derating factor is tabulated in a nations. Aluminum 2 1 10 20 30 40 250 kcmil 300 kcmil 350 kcmil 500 kcmil 600 kcmil conductor ampacity based on the 2011 national electrical code ampacity based on nec table 310. This table indicates the allowable ampacities of insulated conductors in a raceway. An electrical distributor supplying everything from light bulbs and dimmers to plcs and industrial automation equipment. For the allowable ampacities of type mtw wire, see table 11 in nfpa. Next, find the ampacity of the conductors before derating, which is 55 amperes, from table 310.
Allowable ampacities of not more than 3 insulated conductors. Allowable ampacities of insulated conductors rated up to and including. Nec 31016 allowable ampacities of insulated conductors. If there is a spike in temperature or if it drops, a correction factor must be applied. Allowable ampacities insulated conductors in a raceway thank you for seeking out our resources to complete your electrical project. Allowable ampacities of conductors state electric supply. If the temperature in increases, ampacity is reduced and if temperature falls, it is increased. Allowable ampacities of insulated conductors, rated 0 through 2000 volts, 60. It contains allowable ampacities of insulated copper and aluminum or copperclad aluminum conductors rated up to and including 2,000 volts v. The good news is that, in the past, the practice of sizing conductors based on the 90c column never really created a hazard as the ampacities in tables 1 through 4 were substantially lower. The ampacity chart below shows the allowable ampacities of singleinsulated electrical wire rated up to and including 2000 volts in free air, based on ambient air temperature of 30c 86f. Operating performance and problems the aluminum association.
Allowable ampacities of insulated conductors rated 02000 volts as excerpted from the 2002 national electrical code ampacities of not more than three currentcarrying conductors in. Unless otherwise specifically permitted elsewhere in the national electrical code book, the overcurrent protection for conductor types marked with an asterisk. Allowable ampacities of insulated conductors although this is the most common table used to determine wire size, this is just one example. What is wire ampacity and how do you find ampacity rating. Product catalog acsr aluminum conductor, steel reinforced astm conductor sizes diameter inches.
Allowable ampacities of insulated conductors rated 02000 volts as excerpted from the 2002 national electrical code ampacities of not more than three currentcarrying conductors in raceway, cable or earth. Allowable ampacities of insulated conductors rated 02000 volts. You can determine voltage drop of the circuit conductors by. Nec 31016 allowable ampacities of insulated conductors temperature rating of conductor see table 310. Aluminum electrical wire information the aluminum association. The following table is provided for your convenience. Article 310 conductors for general wiring wiring methods and. The allowable ampacity tables, the ampacity tables of article 3. Ps step determine k from the chart in the book step 2determine the cm for this wire from the chart in the book step perform the calculation using the formula in the book drop of 3%. The number and type of electrical devices connected to a circuit determine the ampacity requirement of the conductor. Allowable ampacities for single aluminum conductors in free air based on an ambient temperature of 30 c see rules 4004, 8104, 122210, 14104, 26142, 42008, and 42016 and tables 5a and 5b. Table 2 when counting the number of conductors in a raceway to determine the correlation factor, you must count the bonding conductor.
Electrical code book, the overcurrent protection for conductor types marked with an asterisk shall not exceed 15 amperes for no. Conductor ampacity based on the 2011 national electrical code ampacity based on nec table 310. Allowable ampacities of insulated conductors rated up to and including 2000 volts, 60c through 90c 140f through 194f. Size, copper conductors, aluminum conductors copper clad. B230 aluminum wire, 50h19 for electrical purposes b231 aluminum conductors, concentriclaystranded applications classes aa and a are used primarily for overhead. Ampacity of copper aluminum wire allen allowable ampacities of insulated conductors. Since this 2012 edition ce code has some very significant changes to the ampacities, particular attention must be placed on the application of rule 4006. The same is true for aluminum and copperclad aluminum conductors. Conductor material and sizes section 4 flashcards quizlet. The ampacities are also based on an ambient temperature of 30c 86f. Engineering data for copper and aluminum conductor electrical cables. Amperage is a you must use the correct size wire for the. Ed green electric allowable ampacities insulated conductors.
Browse allowable ampacities of insulated aluminum or copperclad aluminum conductors in the american wire group catalog including. Last month, we covered how the nec addresses voltage drop through a discussion of six fine print notes fpns and several specific rules. Ampacities of insulated conductors from nec table nec310. Sizing conductors, part xi electrical contractor magazine. Engineering data for copper and aluminum conductor. You must use the correct size wire for the current load requirement of the circuit to prevent the wire from overheating. Allowable ampacities insulated conductors in a raceway resources. Sep 26, 2016 again, ampacity ratings are based upon ambient temperatures. Not more than three currentcarrying conductors in raceway, cable, or earth directly buried. C to determine the allowable ampacity of the 3conductor size 6 awg xhhw aluminum ser cable, refer to table 310. Allowable ampacities of insulated copper conductors rated up to and including 2000 volts, 600c through 900c 1400f through 1940f, not more than three currentcarrying conductors in raceway, cable, or earth directly buried, based on ambient temperature of 300c 860f temperature rating of copper conductor table formerly table 310.
Allowable ampacities insulated conductors in a raceway. When subjected to arc currents, the aluminum conductor sulface frequently shows only a removal of sheen, slight roughen ing, and change of color over a considerable area. Unless otherwise specifically permitted elsewhere in this code, the overcurrent protection for conductor types marked with an asterisk shall not exceed 15 amperes for no. Allowable ampacities insulated conductors resources. National electrical code allowable ampacities of insulated. A guide to allowable ampacities insulated conductors. This method for using allowable ampacity tables is a general method and it will be refined in the next article conductor ampacity calculation part four. Allowable ampacities for single aluminum conductors in free air based on ambient temperature of 30c allowable ampacity 60c 75c 8590c 110c 125c 200c size types types see see awg type rw75, r90, rw90, note note bare kcmil tw tw75 t90 nylon 3 3 wire col. The national electrical code has permitted the use of aluminum wire since. Conductor ampacity calculation part seven electrical. Hundreds of electrical products and tools to select from. Not more than three currentcarrying conductors in raceway, cable, or.
Dec 01, 2016 the overall ampacity of insulated cable conductors in a bundle of more than three cables must also be derated, whether in a raceway or cable. In the next article, i will continue explaining the conductor ampacity calculations from tables as provided in 310. While the maximum ampacities are shown, there are limitations. Nec 31016 allowable ampacities of insulated conductors b. The overall ampacity of insulated cable conductors in a bundle of more than three cables must also be derated, whether in a raceway or cable. Unless otherwise specifically permitted elsewhere in the national electrical code book, the overcurrent protection for conductor types marked with an asterisk shall not exceed 15 amperes for no.
The load current rating and the overcurrent protection for conductor types shall not exceed 15 amperes for 14 awg, 20 amperes for 12 awg, and 30 amperes for 10 awg aluminum and copperclad aluminum after any correction factors for ambient temperature and number of conductors have been applied. National electrical code allowable ampacities of national electrical code allowable ampacities of insulated conductors. Table 4 1 allowable short circuit currents of insulated copper and aluminum conductors 14. Allowable ampacities of insulated aluminum or copperclad. Nec 600 volt ampacity tables for electrical cables.
Ratings for 120240 volts, 3wire, singlephase dwelling services. The temperature ratings of conductors include 60c 140f, 75c 167f and 90c 194f. This information presented within this section has been carefully prepared and is believed to be accurate. Please consult a qualified electrician or professional engineer to determine the appropriate values for your specific application. For example, a 10 awg 3c 600 v cable with xhhw singles would have an ampacity of 35 amps if using the 75c column in nec 2014 table 310. Allowable ampacities of insulated copper conductors on. Ampacities vary depending on both the type of conductor and the insulation properties see figure 1. Table 1 table 2 table 1 table 2 free air raceway free air raceway 14 12 10 8 6 4 3 2 1 10 20 30 40 250 300 350 400.
Where the number of currentcarrying conductors in a raceway or cable exceeds three, or where single conductors or multi conductor cables are stacked or bundled longer than 24 inches without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in the following table. Copper and aluminum wire of equal ampacity sizes have equivalent thermal and mechanical performance. Allowable conductor ampacities information is provided as a guideline only. If multiconductor cables are placed in a single layer in uncovered trays, with a maintained spacing of not less than 1 cable diameter between cables, the ampacity of the cables shall not exceed the allowable ambient temperaturecorrected ampacities of multiconductor cables with not more than 3 insulated conductors in free air in accordance with section 310. Conductor ampacity calculation part three electrical.
Conductor ampacity calculation part three electrical knowhow. Conductor ampacity based on the 2011 national electrical code. The ampacity chart below shows allowable ampacities of insulated conductors rated up to and including 2000 volts, 60c through 90c 140f through 194f, not more than three currentcarrying conductors in raceway, cable, or earth directly buried, based on ambient air temperature of 40c 104f. Aluminum conductors resist damage by arcing better than conductors of other metals because the arc tends to cause less pitting and surface metal melting. A raceway is a channel that can mount on a surface such as a desk, for cables to run through, keeping wire clutter to a minimum.