FIW

Breakdown Voltage (BDV) values for FIW will vary depending upon which standard is used to calculate these values.

When using the magnet wire standards for FIW (IEC 60317-0-7 & 60317-56) the BDV is calculated using the minimum insulation increase per size. (min. insulation increase = min. OD including insulation – nominal bare wire dimension).

When using the transformer standard for FIW (IEC 61558-2-16) the BDV calculation mistakenly uses the minimum insulation increase divided in half, erroneously resulting in approximately half the BDV values as the magnet wire standards.

Therefore a new version of IEC 61558-2-16 (new version IEC 61558-1) will be released soon, correcting errors (like the BDV calculation described above) found in the previous version. One major difference: the new version will require the FIW to maintain stability for one minute longer than the magnet wire BDV standard calculation during peak voltage.

Breakdown Voltage Calculation acc. to FIW Standard IEC 60317-0-7

Test is done by cylinder BDV test acc. to IEC 60851-4.3.2. The minimum breakdown voltage has to be calculated for every specific FIW wire size using the increase by insulation and the specific V/µm-value from below table.

 Nominal conductor diametermm Minimum specific breakdown voltageV/µm increase over up to and including at room temperature at 180°C - - 0.100 81 56 0.100 0.355 76 53 0.355 0.500 70 49 0.500 1.000 53 37 1.000 1.600 47 33

NOTE: The specific breakdown voltage is the result of the quotient of the measured value and enamel increase.

Example of formula for calculation of breakdown voltage (BDV):

BDV = min. increase *min. spec. DSP in V/μm

Example: 0.2 mm FIW6 with min. OD 0.303 mm

min. increase = min. OD - nom. dia. = 0.303 mm - 0.2 mm = 0.103 mm = 103 μm

=> BDV = 103 μm x 76 V/μm = 7828 V

FIW Quick Selection

 For the selection of the right FIW wire  key in the Nominal Diameter (in mm) and the FIW Grade in the input fields underneath to calculate the Length, Weight and minimal Breakdown Voltage (acc. to IEC 60317-56) of the specified FIW wire (line 1),  or key in the Nominal Diameter (in mm) and the required minimal Breakdown Voltage (acc. to IEC 60317-56) to get the corresponding FIW Grade of the FIW wire (line 2).
Length [km/kg]???Weight [kg/km]???min. Breakdown Voltage [V]???

2. Nominal Diameter [mm] min. Breakdown Voltage [V]

Calculated Minimum Breakdown Voltage at 20 °C acc. to FIW Standard IEC 60317-56

 NominalDiameter FIW3 FIW4 FIW5 FIW6 FIW7 FIW8 FIW9 min min min min min min min [mm] [V] [V] [V] [V] [V] [V] [V] 0.071 1701 2187 3240 4293 5346 6399 7452 0.080 1782 2349 3483 4617 5751 6885 8019 0.090 1944 2511 3645 4779 5913 7047 8181 0.100 2106 2673 3969 5265 6561 7857 9153 0.106 2052 2660 3952 5244 6536 7828 9120 0.112 2128 2736 4028 5320 6612 7904 9196 0.118 2128 2812 4180 5548 6916 8284 9652 0.120 2280 2964 4332 5700 7068 8436 9804 0.125 2280 2964 4332 5700 7068 8436 9804 0.132 2356 3040 4560 6080 7600 9120 10640 0.140 2432 3192 4712 6232 7752 9272 10792 0.150 2508 3344 5016 6688 8360 10032 11704 0.160 2660 3496 5168 6840 8512 10184 11856 0.170 2736 3648 6232 8056 9880 11704 13528 0.180 2888 3800 5624 7448 9272 11096 12920 0.190 2964 3876 5776 7676 9576 11476 13376 0.200 3040 4028 5928 7828 9728 11628 13528 0.212 3268 4332 6384 8436 10488 12540 14592 0.220 3268 4332 6384 8436 10488 12540 14592 0.224 3268 4332 6384 8436 10488 12540 14592 0.236 3572 4788 7068 9348 11628 13908 16188 0.250 3648 4788 7068 9348 11628 13908 16188 0.265 3800 5016 7372 9728 12084 14440 16796 0.280 3800 5016 7372 9728 12084 14440 16796 0.300 4028 5320 7676 10032 12388 14744 17100 0.315 4028 5320 7676 10032 12388 14744 17100 0.330 4332 5624 7980 10336 12692 15048 17404 0.335 4332 5624 7980 10336 12692 15048 17404 0.350 4332 5624 7980 10336 12692 15048 16030 0.355 4332 5624 7980 10336 12692 15048 16030 0.375 4200 5530 7700 10290 12460 14630 0.400 4200 5530 7700 9870 12040 14210 0.425 4480 5880 8050 10220 12390 14560 0.450 4480 5880 8050 10220 12390 14560 0.475 4690 6160 9030 11900 14770 17640 0.500 4690 6160 9030 11900 14770 0.530 3710 4982 7155 9328 11501 0.550 3763 4982 7155 9328 11501 0.560 3763 4982 7155 9328 11501 0.600 3975 5247 7420 9593 11766 0.630 3975 5247 7420 9593 11766 0.650 4240 5565 7738 9911 12084 0.670 4240 5565 7738 9911 12084 0.710 4240 5565 7738 9911 12084
 bold = item available from stock

Breakdown Voltage Calculation acc. to Transformer Standard IEC 61558-2-16, (Edition 1.0 2013-08)

The voltages given in IEC 61558 will be modified to higher values in IEC 61558-1.

U= (OD - Cu∅) /2 x V/μm x 103  (at 180°C)

 NominalDiameter FIW3 FIW4 FIW5 FIW6 FIW7 FIW8 FIW9 min min min min min min min [mm] [V] [V] [V] [V] [V] [V] [V] 0.071 756 1092 1456 1820 2184 2548 2912 0.080 784 1176 1568 1960 2352 2744 3136 0.090 840 1232 1624 2016 2408 2800 3192 0.100 896 1344 1792 2240 2688 3136 3584 0.106 901 1352 1802 2253 2703 3154 3604 0.112 928 1378 1829 2279 2730 3180 3631 0.118 954 1431 1908 2385 2862 3339 3816 0.120 1007 1484 1961 2438 2915 3392 3869 0.125 1007 1484 1961 2438 2915 3392 3869 0.132 1034 1564 2094 2624 3154 3684 4214 0.140 1087 1617 2147 2677 3207 3737 4267 0.150 1140 1723 2306 2889 3472 4055 4638 0.160 1193 1776 2359 2942 3525 4108 4691 0.170 1246 1882 2783 3419 4055 4691 5327 0.180 1299 1935 2571 3207 3843 4479 5115 0.190 1325 1988 2650 3313 3975 4638 5300 0.200 1378 2041 2703 3366 4028 4691 5353 0.212 1484 2200 2915 3631 4346 5062 5777 0.220 1484 2200 2915 3631 4346 5062 5777 0.224 1484 2200 2915 3631 4346 5062 5777 0.236 1643 2438 3233 4028 4823 5618 6413 0.250 1643 2438 3233 4028 4823 5618 6413 0.265 1723 2544 3366 4187 5009 5830 6652 0.280 1723 2544 3366 4187 5009 5830 6652 0.300 1829 2650 3472 4293 5115 5936 6758 0.315 1829 2650 3472 4293 5115 5936 6758 0.330 1935 2756 3578 4399 6042 6042 6864 0.335 1789 2548 3308 4067 4827 5586 6346 0.350 1935 2756 3578 4399 5221 6042 6864 0.355 1789 2548 3308 4067 4827 5586 6346 0.375 1911 2671 3577 4337 5096 5856 0.400 1911 2671 3430 4190 4949 8709 0.425 2034 2793 3553 4312 5072 5831 0.450 2034 2793 3553 4312 5072 5831 0.475 2132 3136 4141 5145 6150 6909 0.500 2132 3136 4141 5145 6150 0.530 1721 2479 3238 3996 4755 0.550 1721 2479 3571 3996 4755 0.560 1721 2479 3571 3996 4755 0.600 1813 2572 3330 4089 4847 0.630 1813 2572 3330 4089 4847 0.650 1924 2683 3441 4200 4958 0.670 1924 2683 3441 4200 4958 0.710 1924 2683 3441 4200 4958

From 2018 onwards the following table will apply:

In future, IEC 61558-2-16 will refer to IEC 61558-1 and the table in IEC 61558-2-16 will be omitted.

Breakdown Voltage Calculation acc. to Transformer Standard IEC 61558-1, (not published yet)

U=OD - Cu∅ x V/µm x 10³ x 0.85    (at 180°C for 60 seconds)

 NominalDiameter FIW3 FIW4 FIW5 FIW6 FIW7 FIW8 FIW9 min min min min min min min [mm] [V] [V] [V] [V] [V] [V] [V] 0.040 714 904 1428 1904 2380 2856 0.045 809 1047 1618 2142 2666 3189 0.050 809 1095 1618 2142 2666 3189 0.056 904 1238 1761 2332 2904 3475 0.063 1000 1285 1904 2523 3142 3760 0.071 1000 1285 1904 2523 3142 3760 4379 0.080 1047 1380 2047 2713 3380 4046 4712 0.090 1142 1476 2142 2808 3475 4141 4780 0.100 1238 1571 2332 3094 3856 4617 5379 0.112 1261 1622 2388 3154 3919 4685 5451 0.125 1352 1757 2568 3379 4190 5001 5811 0.140 1442 1892 2793 3694 4595 5496 6397 0.160 1577 2072 3063 4055 5046 6037 7028 0.180 1712 2253 3334 4415 5496 6577 7659 0.200 1802 2388 3514 4640 5766 6893 8019 0.224 1937 2568 3784 5001 6217 7433 8650 0.250 2162 2838 4190 5541 6893 8244 9596 0.280 2253 2973 4370 5766 7163 8560 9956 0.315 2388 3154 4550 5947 7343 8740 10136 0.355 2568 3334 4730 6127 7523 8920 10316 0.400 2499 3290 4582 5873 7164 8455 0.450 2666 3499 4790 6081 7372 0.500 2791 3665 5373 7081 8788 0.560 2233 2956 4246 5535 6825 0.630 2359 3114 4403 5692 6982 0.710 2516 3302 4592 5681 7171 0.800 2673 3522 5126 6730 0.900 2831 3743 5347 6950 1.000 2988 3931 5535 7139 1.120 2749 3618 5330 1.250 2805 3703 5414 1.400 2889 3815 5526 1.600 3001 3955 5666

The actual version of the Transformer Standard IEC 61558-16 gives much lower values than IEC 60317-0-7 because

• IEC 60317-0-7 uses the increase of insulation (Outer diameter - Bare wire diameter) for calculation while IEC 61558-2-16 uses the thickness of insulation (Outer diameter - Bare wire diameter)/2 as base, which results in half of the BDV-values of IEC 60317-0-7.
• The specific voltage per micron is given acc. to IEC 60317-0-7 and IEC 61558 at 180 °C and acc. to IEC 60317-0-7 also at room temperature. Actually needed temperature of SMPS (Switch Mode Power Supply) is somewhere in between.
• For calculation of BDV, IEC 60317-0-7 takes the average outer diameter, while IEC 61558 takes the maximum, which results in slightly higher values of IEC 61558.

These differences of BDV values should be clarified with the next revision of IEC 61558.