At first blush, ground sets and jumper sets appear nearly identical. It is a length of insulated cable with a clamp on each end, and both grounds and jumpers are intended to create a temporary path for electrical current to flow outside of the regular path. However, the subtle differences in design and construction of grounds and jumpers ultimately point to the different applications that they cover. Understanding the distinction between jumper sets and ground sets begins with understanding their purpose, followed by an examination of how their individual components support that purpose.

Jumpers Keep The Power Flowing

Utility jumper sets are designed to provide a temporary electrical path that allows current to bypass a de-energized section of conductor while still keeping the system as a whole energized. This enables linemen to safely perform maintenance or repairs without interrupting service to the remainder of the circuit. In practical terms, jumper sets allow customers’ lights to remain on while utility workers are doing maintenance outside.

Ground Sets Keep Linemen Safe

Ground sets serve a fundamentally different role. Rather than maintaining the flow of electricity, they are designed to safely divert it. Ground sets are installed on de-energized conductors or equipment to provide a low-resistance path to ground in the event the system becomes inadvertently energized. It is a safety measure meant to protect utility workers.

Unexpected energization can occur through several mechanisms, including backfeed, induction, or switching errors. Ground sets provide a critical layer of protection by directing fault current away from workers and toward the earth, giving linemen the opportunity to safely clear the line if such an event occurs. Grounds can also be used in creating equipotential zones where voltage differences in the defined area are minimized, thus mitigating the potential for current to flow through the zone. In equipotential zones, even if there is an outside fault causing an increase in system voltage, the increase is uniform within the zone and there will be minimal risk associated with touch or step potential.

Jumper Sets: The Sum of Their Parts

While jumper sets and ground sets share similar basic construction–a length of insulated wire with a clamp on each end–the difference is in the details of the components.

Because jumpers are designed to carry a continuous load of current while in use, the jumper cable must be insulated and rated based on the voltage (15, 25, and 35 kV) and continuous ampacity (the greater the gauge of the wire, the greater the ampacity). The jumper cable needs to be sufficient to not overheat during usage. As with any electrical assembly, a jumper set is only as capable as its lowest-rated component. When configuring jumper sets, it is essential to ensure that the cable, clamps, and ferrules are appropriately rated for the anticipated load.

Tallman Equipment jumper set configurations are available in 15, 25, and 35 kV ratings, with conductor sizes ranging from #2 through 4/0. Larger conductor sizes provide greater ampacity. Although jumper clamps and ferrules are typically rated for 400 amps, the conductor size often becomes the limiting factor. For example, #2 jumper cable is rated at 200 amps, 1/0 at 250 amps, 2/0 at 300 amps, and 4/0 at 400 amps. A jumper set using #2 cable and 400-amp clamps will therefore still be limited to a 200-amp rating. That said, smaller conductor sizes are lighter and more flexible, which can improve ease of handling and installation in the field.

The size and style of clamps for the jumper set is the next major consideration. Clamps are often either chosen based on an ACSR size (such as 477 ACSR) or a conductor diameter range (e.g. 0.162″-2.0″). Different styles of clamps can be used on jumper sets (e.g clear, c-type, and duckbill). Each utility or contractor may have its own standard requirements.

Ground Sets: The Sum of Their Parts

Ground sets offer a little more variety than jumper sets, depending on the application. Straightforward standard ground sets are the most similar to jumper sets ( two clamps, ferrules, copper wire…etc.), but there are also specialty ground set options for different jobs. The variations in those ground sets typically comes down to the kind of clamps or other form of attachment makes the set suitable for situations such as substation grounding or tower grounding or equipment grounding.

Unlike jumper sets, ground sets are not designed to carry continuous current. Instead, their purpose is to safely conduct fault current to ground during abnormal conditions. As a result, grounding cable is generally not rated for high voltage insulation (most grounding cable is rated to 600 V). Grounding wire has minimal insulation that is more concerned with protecting the inner stranding from damage from outside elements.

Ground clamps are where most of the variation lies. C-type clamps can be serrated or un-serrated and are often used on stranded conductor. Flat-face clamps clamp onto flat surfaces like tower legs. All-angle clamps, as the name indicates, offer a variety of approach angles to the conductor to give greater flexibility in setup. Clamps are connected to the conductor via a ferrule. Ferrules are compressed onto the conductor threading for a secure connection without creating too much resistance. The ferrules then connect securely to the clamp to ensure an unimpeded flow of current.

Grounds and Jumpers at Tallman Equipment

Tallman Equipment are your source for the most reliable ground and jumper sets in the utility industry. Sets are built to order with components selected from the most respected brands in the business and a proprietary process that ensures a secure and robust clamp assembly. Sets can often be built the same day to whatever length is required. All assemblies are tested to ensure they are free of defect and serialized for simplified tracking.

Tallman Equipment also specializes in cleaning and refurbishing used grounds and jumpers. The Tallman team fully disassembles, cleans, and tests each component of the jumper and ground assemblies to ensure they are still operating as well as they did when first put into service. Our customers often remark that they cannot believe they are receiving their own equipment back because it truly is in “like new” condition.

Trust Tallman

Tallman Equipment has been serving linemen and the utility industry for over 70 years. We take pride in doing the right thing for our customers, and that includes providing linemen with the best tools and equipment, including ground sets and jumpers, to get the job done. We are committed to being a one stop shop for linemen, where we will always provide quality, convenience, and reliability.