Custom Insulated Jumpers or Macs

Insulated Mechanical Jumper Components and Assemblies

Insulated bypass jumper sets consist of three basic components: a pair of clamps, one pair of ferrules, and a length of insulated cable. JM Test Systems can build your custom mechanical jumper configurations to your specifics.

All Salisbury Insulating Jumpers meet ASTM F2321 standards.

Need custom Jumpers in a Hurry? JM Test Systems can customize to you company's specifics.If you need assembled jumper sets, quickly, send us a message today
and we can configure your insulated jumpers according to your specifications.
1. Specify the style of insulated clamps.

All of the clamps installed wearing rubber insulating gloves, accept either shrouded or unshrouded ferrules, and accept insulated cable up to 4/0, 35kV. Insulated jumper clamps are sold in pairs.

2. Specify the size and length of insulated cable.

Salisbury offers 15kV cable from #2 to 4/0. 25 and 35 kV cable are both available in sizes 1/0 and 2/0. Be sure to specify the length of the cable chosen.

3. Specify if there are any special requirements.

This could include heat shrink tubing, special assembly instructions, markings, packaging etc.


1. Insulated Jumper Clamps

Salisbury Sure-Lok® Jumper Clamp

The Salisbury Sure-lok® Jumper clamp is a revolutionary improvement over any other jumper clamp in the world. Featuring a ratchet type locking mechanism, this is the only clamp available guaranteed not to loosen once installed on a line.

Main Line RangeMax Amps
RatingOAL LengthLbs.
2261477 MCM (.9”-.162”)40036 kV Ø-Ø11.5 (292 mm)10
2271954 MCM (1.25”-.162”)40021 kV Ø-GRD11.5 (292 mm)11
1786477 MCM (.9”-.162”)40036 kV Ø-Ø11.5 (292 mm)8
2116954 MCM (1.25”-.162”)40021 kV Ø-GRD11.5 (292 mm)10

Salisbury Sure-Lock Jumper Clamps



SALCOR® Insulated Jumper Clamps
SALCOR® Jumper Clamps are available in two main line sizes with a maximum use voltage of 35kV. The SALCOR Jumper Clamp not only provides a superior grip, but also resists ozone cutting and tracking. Being molded of rubber, these handles are inherently impact resistant and extremely durable. The body and jaw are made from a copper base alloy.


Main Line RangeMax Amps
RatingOAL LengthLbs.
2260477 MCM (.9”-.162”)40036 kV Ø-Ø11.5 ( 292 mm)10
2270954 MCM (1.25”-.162”)40021 kV Ø-GRD11.5 (292 mm)11
SALCOR Insulated Jumper Clamps


Clear Plastic & FRP Insulated Jumper Clamps
Salisbury’s superior stress cracking resistant Clear Jumper Clamps are available in two main line sizes with a maximum use voltage of 35kV. Assemble these clamps with insulated jumper cable and 5/8” – 11 NC threaded ferrules.

Clear Plastic Jumper Clamps – compact lightweight, and virtually unbreakable.

FRP Jumper Clamps – designed for maximum loads, voltages, and cables.



Main Line RangeMax Amps
RatingOAL LengthLbs.
1610954 MCM (1.25”-.162”)40036 kV Ø-Ø11 (279 mm)14
1785477 MCM (.9”-.162”)40036 kV Ø-Ø11.5 (292 mm)8
2115954 MCM (1.25”-.162”)40021 kV Ø-GRD11.5 (292 mm)10
Clear Plastic and FRP Insulated Jumper Clamps in stock at JM Test Systems



2. Flexible Insulated Jumper Cables

Flexible Insulated Jumper Cables are lightweight and resistant to oil, heat, moisture, ozone and abrasion. The cable is embossed every three feet with conductor size and kV rating. All jumper cables use fine stranded conductor and a new EPR low temperature Unipass orange CV cured jacket. The fine stranded copper conductor is alloy coated and assembled in a unidirectional rope lay for extra flexibility. The conductor has a semiconducting shield surrounding it to relieve voltage stress and improve dielectric strength and service life.

Cable meets requirements of ASTM F2321.

Jumper Cables Meet Requirements of ASTM F2321

Model #Sz and Str. AWGkV Rating Ø to ØNominal Ø to GrdStr. Dia In. (mm)O.A Dia. in. (mm)Maz Amps ContinousWeight lbs.per 1000 ft. kgs
2754#2-259W1510.320 (8.1).75 (19)200440199
27551/0-413W1510.403 (10.2).83 (21)250600272
27562/0-427W1510.456 (11.5).90 (23)300710322
27574/0-437W1510.592 (15.0)1.01 (25.6)4001050476
213001/0-413W2515.403 (10.2)1.06 (27)250650295
210602/0-427W2515.456 (11.5)1.10 (28)300750341
20591/0-413W3520.403 (10.2)1.22 (31)250950431
43702/0-427W3520.48 (12.1)1.31 (33.1)3001060482


3. Ferrules – Shrouded / Unshrouded

Ferrules are manufactured in two different styles: unshrouded and shrouded.

Shrouded ferrules are compressed on both the conductor and the insulating jacket of the high voltage EPR cable to reduce bending stress.

Shrouded ferrules are designed to be used on glove-installed high voltage jumpers. Unshrouded ferrules are crimped to the conductor strands only and can be used on either stick- or glove-installed jumpers.

Ferrules are manufactured of 99.5% pure copper with industry standard 5/8”-11 NC threads.

Ferrules are topped with a brass hex jam nut and toothed stainless steel lockwasher.

Jumper Ferrules


Model #Cable SzStrand Die Codes T&BJacket Die Codes T&BBurndy Die NumberWeight
2012#2-15 kV ERP661061.2 (.5)
20131/0-15 kV ERP661061.2 (.5)
20142/0-15 kV ERP661061.1 (.5)
20154/0-15 kV ERP661060.9 (.4)
213531/0-25 kV661121.1 (.5)
213542/0-25 kV661121.1 (.5)
213562/0-35 kV661121.1 (.5)
Unshrouded – Tin PlatedStrand Die Codes
2022#250U2430.5 (.2)
20231/050U2430.4 (.2)
20242/060U2450.4 (.2)
20254/066U2470.6 (.3)
Add suffix “A” to the catalog number when requesting a custom insulated jumper set.

Request a Custom Insulated Jumper Cable