The T. J. Snow Company An air cooled cable end

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Air Cooled Jumper Cables

Each air cooled cable is manufactured with completely silver plated terminals, which can be manufactured up to 3-7/8" long for special applications.

A chart for sizing the correct gauge cable is towards the bottom of the page, as well as guidelines for installation.

To order an air cooled cable, you need to know several specifications for that cable. The following will walk you through this process.

1. Select Styles of Terminal Ends:
End Styles End Combinations
F Style Dry Jumper End
The first "DJ" stands for Dry Jumper.
The part number after this describes the two ends.

Types of terminal Ends

FR-90 Style Dry Jumper End
L Style Dry Jumper End
VO Style Dry Jumper End
V Style Dry Jumper End
LO Style Dry Jumper End

2. Taking Measurements:
Length of the Cable   = L
Terminal Face Width = B
  • To get L, 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. 
How to measure the length of a Dry Jumper Cable

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

Terminal Thickness
MCM 1.250" Wide 1.375" Wide 1.500" Wide
400 0.405" 0.370" N/A
500 0.510" 0.465" 0.425"
600 0.540" 0.490" 0.450"
750 0.650" 0.590" 0.545"
1000 0.825" 0.750" 0.690"
1200 0.965" 0.880" 0.805"
1500 1.165" 1.060" 0.975"
2000 N/A 1.575" 1.440"

  • The standard terminal width is 1-1/4". If a 1-3/8" or 1-1/2" wide terminal is desired, please be sure to specify this.
  • If you are unsure of what MCM your application requires, you can size the correct cable yourself.



    3. More Cable Options:
    Isolated Conductor
    Cables with isolated, individually wrapped conductors increase cable life by preventing common failure points:
    • Eliminated Frictional wear between adjacent copper ropes by encasing them in rubber tube.
      • Reduces the number of friction points for wear between strands from 36 to 9, in the rope cross section.
    • Reduced strand failure at the rear terminal by adding a Stabilizer flare.
    • Increased flexibility due to the fact that a standard lapped cover is not required.
    Note: Thermal tests have indicated that the operating temperatures of this style is virtually identical to that of standard jumper using a lapped cover.
    Isolated Conductor Air Cooled Cable
    Stabilizer Collar
    Increased strand life at the cable terminal is the advantage of a stabilizing collar. It slightly increases the minimum flex radius for the jumper, reducing over flexing. 


    Extra Flexible
    36 AWG copper rope stranding and an extra flexible protective cover are used to create an extra flexible jumper. The result is a jumper that is over twice that of a regular jumper. This makes it ideal for robotic applications and where limited space makes standard cables a hard fit. 
    The DJ-XF is available in 750, 1000, and 1200 MCM. Other options include a perforated cover or a special Hypalon high temperature cover, able to withstand 300F to -30F.
    Extra Flexible Air Cooled Jumper


    How to install air cooled cables

    Air Cooled Jumpers
    Good Working shapes for Air Cooled Cables
    Air cooled jumpers should be installed in such a manner that the mechanical stresses at the terminals will be reduced to a minimum. This may be accomplished by installing the jumper with a little slack, which will allow the jumper to flex freely. 
    Bend radii should not be sharp, and should be distributed throughout as much of the jumper as possible, in order to distribute the frictional wear over the greatest possible area. See the below charts for suggested minimum bend radii.  
    Recommended Minimum Bend Radii:
    500 MCM and Below 2"
    600 MCM - 1500 MCM 3"
    Minimum Distance from the end of the
    hose to the point where the bend radii
    should start is:
    350 MCM - 600 MCM 2"
    750 MCM 2-1/2"
    1000 MCM 3"
    1200 MCM 3-1/2"
    1500 MCM 4"


    Air Cooled Jumper Sizing

    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 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 complete the selection.

    Example Data:
    6 cycles of current "on time" per weld
    60 welds per minute
    10,000 amps per weld
    10 inch cable Length


    Conversion Factor and Duty Cycle Chart

    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.
    Selection chart for sizing air cooled jumpers

    More Specifications

    D.C. Resistance of Single Conductor
    Air Cooled (and water cooled) Cables
    MCM D.C. Resistance
    (Ohms per foot at 70C)
     350 .0000376
     400 .0000322
     500 .0000263
     600 .0000217
     750 .0000172
    1000 .0000130
    1200 .0000110
    1500 .0000088
    2000 .0000066

    120 Nowlin Ln
    P. O. Box 22847
    Chattanooga, TN 37422
    (423) 894-6234
    FAX (423) 892-3889
    ORDER FAX (423) 490-2417
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