Air-Cooled Jumper Cables

Use the following method to determine what size cable should be used for your application. First you use the Conversion Factor chart to determine your “Continuous Duty Current”; then you read the correct size cable off the second chart. An example is worked out below.

Step 1: Lay one side of a straight edge across the graph at the six cycles of the current “one-time” point (the left-hand vertical scale of the conversion factor chart).

Step 2: Pivot the other end of the straight edge across to line up with the “60 welds per minute” on the far right vertical scale.

Step 3: At the intersection of your straight edge with the diagonal conversion factor scale line, you should be able to read a conversion factor of .32 off the lower 1/2 of the line.

Step 4: Multiply the required current (10,000 amps) by the conversion factor (.32) to get the “continuous duty current” of 3,200 amps. Now proceed to the Air-Cooled Jumper Selection Chart to read and complete the selection.

Step 5: Line up your straight edge on the 3200 continuous duty amp mark, and find the intersection with your desired length line (from below).

Step 6: Any cable whose line is above this point may be safely used since the load it would carry will be within its thermal capacity. In this example, a 1200 MCM cable can be used and stay within design tolerances.

The length is measured from the bolt hole centers at each end of the cable on straight or 45” terminals. It is measured from the extreme ends of 90 terminals. On terminals with two holes, measure from the centers of the outer holes.

To get LENGTH, measure from the center of one set of mounting holes to the center of the second set.

The secondary measurement, B, is the face width.

The terminal thickness is dependent on the terminal face width, and the gauge of the cable, as outlined in the table on the right.