1、 ANSI/CTA Standard Mobile Electronics Cabling Standard ANSI/CTA-2015 R2017 (Formerly ANSI/CEA-2015) May 2007 NOTICE Consumer Technology Association (CTA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manu
2、facturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards, Bulletins and other technical publications shall not in any respec
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6、ty problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this document to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. This document is copyrighted by the C
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8、e agreement. Requests to reproduce text, data, charts, figures or other material should be made to the Consumer Technology Association (CTA). (Formulated under the cognizance of the CTA R6 Portable, Handheld and In-Vehicle Electronics Committee.) Published by CONSUMER TECHNOLOGY ASSOCIATION 2017 Tec
9、hnology Phone 800-699-9277; Fax 734-780-2046; Internet http:/; Email 2.2 Informative References The following references contain provisions that, through reference in this text, constitute informative provisions of this standard. At the time of publication, the edition indicated was valid. All stan
10、dards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. 2.2.1 Informative Reference List CEA-2006-A, Testing Phone 800-699-9277; Fax 734-780-2046; Internet http:
11、/; Email National Electric Code: National Fire Protection Association, 1 Batterymarch Park, Quincy, MA, USA 02169-7471; Phone +1 617 770-3000; Internet http:/www.nfpa.org 2.3 Symbols and Abbreviations AWG American Wire Gauge IACS International Annealed Copper Standard 2.4 Compliance Notation As use
12、d in this document “shall” and “must” denote mandatory provisions of the standard. “Should” denotes a provision that is recommended but not mandatory. “May” denotes a feature whose presence does not preclude compliance, and implementation of which is optional. “Optional” denotes items that may or ma
13、y not be present in a compliant device. 3 Conductor Design Conductors shall be composed of multiple strands of copper wire. Conductors shall comply with the size, resistivity and strand count requirements defined in Table 1. AWG gauges are defined in ASTM B 258, Standard Specification for Standard N
14、ominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors, Rev. 02. 5 Table 1: Size, Conductor Resistivity and Strand Count Requirements for CEA Wire Gauges Gauge Cross Sectional Area Minimum Strand Count for Entire Cable Minimum # of Groups Resistanc
15、e per meter NOM (milliohms) Resistance per meter MAX (milliohms) cmills NOM cmills MIN mm2NOM mm2MIN 0000 AWG 211,565 198,934 107.2 100.8 3174 45 0.17 0.18 000 AWG 167,752 157,686 85.0 79.9 2517 45 0.22 0.23 00 AWG 133,017 125,123 67.4 63.4 1997 45 0.27 0.29 0 AWG 105,585 99,269 53.5 50.3 1584 18 0.
16、35 0.37 1 AWG 83,678 78,744 42.4 39.9 1255 18 0.44 0.46 2 AWG 66,311 62,364 33.6 31.6 995 18 0.55 0.59 3 AWG 52,693 49,536 26.7 25.1 789 6 0.69 0.74 4 AWG 41,641 39,076 21.1 19.8 626 6 0.88 0.93 5 AWG 33,155 31,182 16.8 15.8 496 6 1.10 1.17 6 AWG 26,248 24,669 13.3 12.5 394 6 1.39 1.48 7 AWG 20,919
17、19,735 10.6 10.0 312 6 1.75 1.85 8 AWG 16,518 15,531 8.37 7.87 248 6 2.21 2.35 9 AWG 13,084 12,295 6.63 6.23 196 6 2.79 2.97 10 AWG 10,380 9,749 5.26 4.94 156 6 3.52 3.74 11 AWG 8,229 7,736 4.17 3.92 123 6 4.44 4.72 12 AWG 6,532 6,137 3.31 3.11 98 6 5.59 5.95 13 AWG 5,190 4,874 2.63 2.47 78 6 7.03 7
18、.49 14 AWG 4,104 3,868 2.08 1.96 62 6 8.89 9.44 15 AWG 3,256 3,059 1.65 1.55 49 6 11.21 11.94 16 AWG 2,585 2,427 1.31 1.23 39 1 14.12 15.04 17 AWG 2,052 1,934 1.04 0.98 31 1 17.79 18.88 18 AWG 1,624 1,527 0.823 0.774 24 1 22.48 23.90 19 AWG 1,288 1,211 0.653 0.614 19 1 28.33 30.13 20 AWG 1,024 963 0
19、.519 0.488 15 1 35.65 37.91 6 4 Power Handling Capability The power handling capability of any cable is dependent on the material used to make the cable, and the size of the cable. The lower the resistivity of the conductive material used in the cable, the more power it can handle, all else being eq
20、ual. Also, the larger the cross-sectional area of the cable the more power it can handle, all else being equal. CEA-2015 rates power cables and speaker cables differently. 4.1 Power Cables Power cables are rated in terms of the amplifiers with which they should be used. When amplifier power is measu
21、red in accordance with CEA-2006-A the amplifier power that is reported to consumers for a particular product is not equivalent to the power consumed by that product. Instead, it represents the power delivered to 4 ohm speakers. In order to convert this number to power consumed by the amplifier one n
22、eeds to factor in the efficiency of the amplifier. For example, if an amplifier is rated as a 50 watt per channel x 2 channel amplifier using CEA-2006-A, and the efficiency of the amplifier is 50 percent, then only 50 percent of the power supplied to the amplifier makes it to the speakers, and the t
23、otal power consumed by the amplifier is 200 watts (50 watts per channel x 2 channels divided by 0.5). So, in order to supply power to the CEA-2006-A-rated amplifier in this example, the power cables must be able to handle 200 watts of power. CEA-2015 assumes a standard efficiency of 50 percent for a
24、ll amplifiers, which is typical performance for a class AB amplifier. While some amplifiers may be more efficient than this, it is believed that a 50 percent efficiency assumption for all amplifiers will ensure that the CEA-2015-rated capacity of power cables will be equal to or greater than the pow
25、er consumption of amplifiers if their output power is rated in accordance with CEA-2006-A. Once the amount of power that needs to be delivered to the amplifier by the cable is known the next step is to determine the current flowing through the cable. Current equals power divided by voltage. We know
26、the power, and we also know that the voltage supplied to the amplifier is coming from a car battery. For CEA-2015 purposes it is assumed that the car battery is supplying 14.4 V DC, and that there is a 0.25 V DC drop in the cable supplying power to the amplifier. With these assumptions the current f
27、lowing through the cable is: cable in dropped volts 0.25 -voltsbattery 14.42 x watts)in power amplifier total ratedA -2006-(CEAcable in current = The “x 2” in the above equation is a result of the assumption that only 50 percent of the power consumed by the amplifier makes it to the speakers. Once t
28、he amount of current in the cable that corresponds to the assumed 0.25 V drop in the cable is known, the resistance in the cable can be calculated. The resistance in the cable in ohms is equal to the voltage drop in the cable in volts (assumed to be 0.25 V) divided by the current in the cable in amp
29、eres. Substituting the above formula for calculating the current into this equation results in a formula that determines cable resistance as a function of the battery voltage, the voltage dropped in the cable, and the CEA-2006-A rated power of the amplifier, as follows: 2 x watts)in power amplifier
30、total ratedA -2006-(CEAcable) in dropped volts 0.25 - voltsbattery (14.4 V x 0.25)( cable of resistance = In other words, using the CEA-2015 assumptions about amplifier power and voltage drop in the power cable, the maximum amount of resistance that the power cable can have is: wattsin power amplifi
31、er total ratedA -2006-CEAvolts 1.77)( cable of resistance2= 7 The next step is to determine the length of cable beyond which the maximum amount of permitted resistance is exceeded. The formula for determining the resistance of a length of cable is: area sectional-crosslengthy x resistivitresistance
32、= Thus, yresistivitarea) sectional-(cross x resistancelength = CEA-2015 defines the maximum resistivity1of the conductor material in a mobile electronics cable as 1.85 x 10-8ohm meters, which is based on 93.15% IACS copper. Plugging this and the formula for cable resistance as a function of CEA-2006
33、-A rated amplifier power into the above equation yields the formula for maximum power cable length as a function of CEA-2006-A rated amplifier power and cable cross-sectional area.2m 10 x 1.85 x W)in power amplifier total ratedA -2006-(CEA)m in area sectional-(cross x volts 1.77m in length maximum8-
34、22= CEA-2015 sets upper and lower limits on the cross-sectional area of a cable as a function of wire gauge, as defined in Table 1. When calculating the appropriate maximum length of cable of a particular wire gauge the lower limit value for cross-sectional area for that gauge shall be used. Thus, p
35、lugging the lower limit value for each wire gauge from Table 1 into the above formula yields a table that defines maximum cable length for each wire gauge in terms of CEA-2006-A rated amplifier power. Note that this is the maximum total cable length, which is the sum of the lengths of both the posit
36、ive and negative leads. That is, the combined length of the positive lead plus the length of the negative lead shall not exceed the maximum limit defined by the above equation. To ensure that the current flowing through the recommended cable length is not excessive, the cable thickness per ampere, i
37、n terms of circular mils per ampere, shall be compared against the appropriate limit. This limit is derived by consulting Table 310.17 of the National Electric Code to determine the ampacity of a copper conductor of a given AWG cable that is rated for 90 C when the ambient temperature is in the rang
38、e 71-80 C. The circular mils per ampere limits that are derived from Table 310.17 of the National Electric Code are presented in Table 2. 1ASTM B 258 02 defines resistivity in terms of ohm*grams per square meter. Resistivity is normally defined in terms of ohm*meters. For the purposes of CEA 2015, t
39、he more common definition of ohm*meters is used. To determine the CEA 2015 resistivity for a material listed in Table 2 of ASTM B 258 02, divide the ASTM “resistivity” value (ohm*pounds per square mile) by 5710 to get ohm*grams per square meter, and then divide the result by the ASTM B 258 02 densit
40、y value (grams per cubic centimeter) and divide that result by one million cubic centimeters per meter to get a resistivity value in ohm*meters. For other sources that list the resistivity of a material in terms of ohm*meters, simply use the listed value. Resistivity values shall be rounded to no fe
41、wer than three significant figures, and when resistivity in ohm*meters is calculated from other values, no rounding shall occur until the final ohm*meter number has been calculated. 2The cable cross-sectional area for the different AWG sizes is defined in Table 1 of ASTM B 258 02. To convert square
42、millimeters to square meters, divide square millimeters by one million. 8 Table 2: Circular Mil per Ampere Limits for Various Wire Gauges Rated for 90 C in Ambient Temperature of 71-80 C Cable Gauge Circular Mil per Ampere Limit 0000 1199 000 1099 00 1018 0 932 1 873 2 801 3 733 4 680 51627 6 574 71
43、524 8 474 91454 10 433 111404 12 375 131323 14 270 151259 16 247 171227 18 207 191207 201207 1Table 310.17 of the National Electric Code does not contain ampacity data for 5, 7, 9, 11, 13, 15, 17, 19 or 20 AWG cable. For gauges 5, 7, 9, 11, 13 and 17 the average of the two adjacent even numbered gau
44、ges ampacity was used when determining the appropriate limit. For gauges 19 and 20 the 18 AWG ampacity figure was used. 9 Table 3: Maximum Power Cable Length in Terms of CEA-2006-A Rated Total Amplifier Power in Meters (Feet) Cable Gauge Maximum Current (Amps) 10 W Total 25 W Total 50 W Total 75 W T
45、otal 100 W Total 150 W Total 250 W Total 500 W Total 750 W Total 1,000 W Total 0000 166 990 (3248) 396 (1299) 198 (649) 132 (433) 99 (324) 66 (216) 39 (129) 19 (64) 13 (43) 9 (32) 000 143 785 (2575) 314 (1030) 157 (515) 104 (343) 78 (257) 52 (171) 31 (103) 15 (51) 10 (34) 7 (25) 00 123 622 (2043) 24
46、9 (817) 124 (408) 83 (272) 62 (204) 41 (136) 24 (81) 12 (40) 8 (27) * 0 107 494 (1621) 197 (648) 98 (324) 65 (216) 49 (162) 32 (108) 19 (64) 9 (32) 6 (21) * 1 90 392 (1285) 156 (514) 78 (257) 52 (171) 39 (128) 26 (85) 15 (51) 7 (25) * * 2 78 310 (1018) 124 (407) 62 (203) 41 (135) 31 (101) 20 (67) 12
47、 (40) 6 (20) * * 3 68 246 (808) 98 (323) 49 (161) 32 (107) 24 (80) 16 (53) 9 (32) * * * 4 57 194 (638) 77 (255) 38 (127) 25 (85) 19 (63) 12 (42) 7 (25) * * * 5 50 155 (509) 62 (203) 31 (101) 20 (67) 15 (50) 10 (33) 6 (20) * * * 6 43 122 (402) 49 (161) 24 (80) 16 (53) 12 (40) 8 (26) 4 (16) * * * 7 38
48、 98 (322) 39 (128) 19 (64) 13 (42) 9 (32) 6 (21) 3 (12) * * * 8 33 77 (253) 30 (101) 15 (50) 10 (33) 7 (25) 5 (16) * * * * 9 27 61 (200) 24 (80) 12 (40) 8 (26) 6 (20) 4 (13) * * * * 10 23 48 (159) 19 (63) 9 (31) 6 (21) 4 (15) 3 (10) * * * * 11 19 38 (126) 15 (50) 7 (25) 5 (16) 3 (12) * * * * * 12 16
49、 30 (100) 12 (40) 6 (20) 4 (13) 3 (10) * * * * * 13 15 24 (79) 9 (31) 4 (15) 3 (10) 2 (7) * * * * * 14 14 19 (63) 7 (25) 3 (12) 2 (8) 1 (6) * * * * * * For this CEA-2006-A rated amplifier power, this cable gauge shall not be used 10 4.2 Speaker Cables The signal loss (SL) in the speaker cable is a function of the voltage supplied by the amplifier (Va) and the voltage drop across the speaker (Vs), and is calculated as follows: =VaVsSLdB log20 Note: Because SL is a
