Determining the MCM size required To determine the required MCM rating, it is first necessary to know: (1) the duty cycle, (2) current to be used and (3) length of the cable to be used, measured bolt hole center to bolt hole center. Once this has been determined, proceed as follows: 1. Find the closest duty cycle shown on the multiplier chart to the left. Take your current level and multiply it times the multiplier shown. This will give you the continuous duty current of the cable.
2. Refer to the chart below. Looking up from the length of your required cable, find the angular line closest to the continuous current level you just established. Then follow the angular line to the right for the
