The following charts are for use in determining current carrying capacity and sizes of copper tracks for various temperatures above ambient.

Notes: 1. The design chart has been prepared as an aid in estimating temperature rises (above ambient) vs. current for various cross-sectional areas of etched copper conductors. It is assumed that, for normal design, conditions prevail where the conductor surface area is relatively small compared to the adjacent free panel area. The curves as presented include a nominal 10 percent derating (on a current basis) to allow for normal variations in etching techniques, copper thickness, conductor width estimates, and cross- sectional area. 2. Additional derating of 15 percent current-wise is suggested under the following conditions: (a) For panel thickness of 0.8mm or less (b) For conductor thickness of 105mor thicker. 3. For general use the permissible temperature rise is defined as the difference between the maximum safe operating temperature of the laminate and the maximum ambient temperature in the location where the panel will be used.

4. For single conductor applications the chart may be used directly for determining conductor widths, conductor thickness, and current-carrying capacity for various temperature rises.

5. For groups of similar parallel conductors, if closely spaced, the temperature rise may be found by using an equivalent cross-section and an equivalent current. The equivalent cross section is equal to the sum of the cross section of the parallel conductors, and the equivalent current is the sum of the currents in the conductors.

6. The effect of heating due to attachment of power dissipating parts is not included.

7. The conductor thicknesses in the design chart do not include conductor overplating with metals other than copper.

copy of IPC-1-00005