What Are the Risks of Using Nonstandard Grounds on Live Lines?

Using nonstandard grounding equipment on or near live lines creates a risk that is fundamentally different from using an ordinary low-voltage earth connection. In high-voltage work, a temporary grounding set is part of the worker’s protective system: it is expected to carry fault current, limit dangerous voltage differences, remain mechanically secure, and withstand the thermal and electromagnetic forces produced during a fault. If any element fails, the grounding set can become the source of the hazard rather than the control against it.

The most important point is often overlooked: a conventional portable protective ground is normally installed only after the circuit has been isolated, verified de-energized, and controlled under an approved work procedure. Deliberately applying a standard grounding set directly to an energized conductor may create a phase-to-ground fault. Live-line work requires specifically engineered methods, tools, clearances, switching control, and procedures. A grounding device that is merely “conductive” is not automatically suitable for use around energized systems.

What makes grounding equipment “nonstandard”?

Nonstandard does not only mean unbranded or visibly poor-quality equipment. It can include a grounding assembly that lacks a verifiable electrical rating, uses mismatched components, has undocumented conductor material, has been modified in the field, or is applied outside the conditions for which it was designed.

A temporary protective grounding system is an assembly rather than a single cable. It commonly includes grounding clamps, ferrules or terminals, flexible copper cable, a grounding cluster or junction, grounding electrodes or station ground connections, and application tools. Its protection level depends on the weakest part of that chain.

Relevant standards vary by jurisdiction and utility practice, but recognized references include ASTM F855 for temporary protective grounds used on de-energized electric power lines and equipment, and IEC 61230 for portable equipment for earthing or earthing and short-circuiting. Compliance with a standard does not eliminate the need to confirm suitability for the actual fault duty, installation arrangement, voltage class, and work method. It does, however, provide an auditable basis for evaluating electrical, mechanical, and construction requirements.

A grounding set can fail under fault conditions even when it looks intact

The central technical risk is inadequate fault-current performance. A protective ground is not selected according to normal load current. It must be able to carry the available short-circuit current for the required clearing time without losing continuity or creating conditions that injure workers.

During a fault, current can rise dramatically before a breaker or protective relay clears the circuit. The conductor, clamps, and connections are subjected to several stresses at once:

• Thermal stress: I²t energy heats cables, ferrules, and clamp contacts. An undersized conductor can anneal, melt, or rupture.
• Electromagnetic force: High fault current produces strong mechanical forces. Cables may whip, clamps may move, and poorly secured assemblies may separate.
• Arc energy: A loose or contaminated contact can form an arc. The connection may burn away before protective devices operate.
• Voltage rise: Even when the ground remains connected, its impedance and the station grounding system determine the voltage difference that can appear across the worker’s body.

A cable with the same visible diameter as an approved grounding lead may not have the same cross-sectional area, stranding construction, copper quality, terminal crimping, or short-circuit withstand capability. Appearance is not a meaningful substitute for a verified rating.

Electric shock risk is driven by voltage difference, not simply by whether a ground is present

A common misconception is that any connection to earth makes a work location safe. In reality, grounding protects workers by helping create an equipotential work zone. The objective is to keep the worker, conductor, structure, and bonding points at substantially the same electrical potential if an accidental energization occurs.

A nonstandard grounding arrangement can leave dangerous differences between those points. If the line becomes energized through backfeed, induction, incorrect switching, generator connection, or contact with another circuit, current may divide through the grounding path, structure, soil, equipment, and potentially the worker.

This creates several exposure paths:

• Touch voltage: a worker contacts two conductive points at different potentials, such as a grounded conductor and metal structure.
• Step voltage: voltage gradients in the ground expose a person whose feet are at different potentials.
• Transferred potential: a remote grounding point introduces voltage onto a conductor, vehicle, fence, or metallic pathway at the work site.
• Induced voltage: parallel energized circuits can induce voltage on isolated lines, especially on long transmission or distribution sections.

Improper grounding location is as dangerous as inadequate cable capacity. A grounding set connected far from the worker may provide a path for fault current but still fail to establish an acceptable equipotential zone at the point of work. The effective arrangement must be based on the system configuration and the approved work method, not on the assumption that “grounded somewhere” is sufficient.

Applying unsuitable equipment to an energized line can cause an immediate fault

Where “using grounds on live lines” means connecting a portable ground directly onto an energized phase conductor, the principal hazard is immediate fault initiation. The result can include arc flash, arc blast, equipment damage, relay operation, conductor damage, or widespread service interruption.

The severity depends on available fault current, system grounding method, protection settings, and the point of connection. It should never be assumed that a ground connection will harmlessly “bleed off” voltage from a utility line. On a power system, grounding an energized phase may be equivalent to placing a deliberate short circuit on the network.

There are limited circumstances in which energized-system grounding operations are performed under specialized utility procedures, but these are not ordinary portable-ground applications. They require engineered work methods, system knowledge, correctly rated devices, insulated tools, defined approach boundaries, competent authorization, and coordination with system operations. Substituting a generic grounding clamp and cable for an approved live-line device is not an acceptable shortcut.

Arc flash and arc blast can result from poor clamp contact

Clamp quality matters because the interface between clamp jaws and the conductor or grounding point often determines whether the assembly can conduct fault current safely. Nonstandard clamps may have weak spring force, inadequate contact area, poor thread design, unsuitable jaw geometry, or plating that degrades in outdoor service.

Oxidation, paint, corrosion, grease, ice, and damaged conductor surfaces increase contact resistance. If a clamp is tightened onto an unsuitable surface, it may appear secure while having insufficient electrical contact. Under fault conditions, resistance at that point produces rapid localized heating. The metal can fuse, the clamp can be expelled, and an arc can develop.

Arc flash is not limited to enclosed switchgear. An outdoor line or substation connection can still release intense heat, molten metal, pressure, sound, and ultraviolet radiation. A grounding set that opens or ejects under fault current may also leave the worker exposed to a line that was believed to be protected.

Mechanical failure can turn a grounding cable into a moving hazard

Fault current produces electrodynamic forces that increase with current magnitude and are particularly severe during the initial asymmetrical portion of a short circuit. A grounding cable that is loosely routed, sharply bent, poorly supported, or connected with incompatible hardware can move violently.

Cable whip can strike personnel, damage insulating equipment, dislodge clamps, or create unintended contact with adjacent phases. Improvised cables and repaired leads are especially problematic because hidden damage near ferrules or beneath insulation may reduce both mechanical strength and electrical continuity.

Routing also affects worker exposure. A grounding lead should not be positioned where a worker could be trapped between it and a structure, where it can cross an access path, or where a fault-driven movement would pass through the work position. Equipment suitability includes installation behavior, not just nameplate rating.

Nonstandard grounds undermine switching safety and operational control

Temporary grounding is often one of the final barriers in an isolation process. If the grounding equipment is undocumented, untested, or assembled from mixed parts, the organization loses confidence in that barrier. This affects more than the individual task.

An uncertain grounding arrangement can complicate switching authorization, lockout and tagging records, permit-to-work controls, and post-event investigation. It can also lead to conflicting assumptions between the field crew and system operator: one party may believe that a section is protected by grounds while the actual installation does not meet the approved design or has been connected to an unsuitable grounding point.

For contractors and cross-border procurement teams, documentation is part of the safety function. Product specifications should clearly identify the applicable standard, conductor size and construction, clamp type, rated short-circuit withstand duty, intended application, traceability markings, and inspection requirements. A supplier declaration without corresponding technical documentation does not establish that an assembly is fit for a particular network fault level.

Why mixing components is a frequent but serious error

Temporary grounding assemblies are sometimes created from cables, clamps, and connectors obtained from different sources. This can be acceptable only when the complete assembled system has been evaluated for compatibility and rating. Otherwise, the finished set may have no valid performance basis.

A high-capacity cable does not compensate for an underrated clamp. Similarly, a robust clamp does not make a damaged ferrule or undersized grounding cluster safe. Changes in cable length can also affect routing, impedance, mechanical loading, and the ability to establish the required work-zone configuration.

Inspection is necessary, but it cannot validate an unknown design

Visual inspection before use remains essential. Crews should look for broken strands, flattened cable sections, cracked insulation or protective sheathing, damaged ferrules, loose hardware, corrosion, jaw wear, missing markings, and evidence of overheating. Clamps should operate smoothly and provide secure contact on the intended conductor or grounding point.

However, a visual check cannot prove short-circuit capability. A cable may have internal strand damage, a crimp may have degraded beneath a sleeve, and a clamp may retain its shape despite prior thermal overload. Periodic electrical and mechanical inspection should follow the equipment manufacturer’s instructions and the employer’s safety program. Equipment with uncertain history, altered configuration, missing identification, or suspected fault exposure should be removed from service until evaluated by a competent party.

It is also unsafe to assume that a continuity test alone establishes suitability. Continuity confirms that a conductive path exists at low test current. It does not demonstrate that the assembly will survive the thermal and mechanical demands of an actual system fault.

The right decision begins with the work method, not the cable catalogue

Grounding equipment should be selected only after the task has been classified correctly: de-energized maintenance with temporary protective grounds, induced-voltage control, substation work, distribution work, transmission-line work, or an authorized energized-line procedure. Each situation has different constraints.

Before equipment is issued, the responsible engineering or safety function should establish the available fault current and clearing time at the work location; the required grounding configuration; the approved connection points; the need for equipotential bonding; the influence of parallel circuits, backfeed sources, and distributed generation; and the applicable regulatory or utility requirements. The equipment rating must match those conditions with appropriate margin under the governing standard and internal procedure.

The risks of using nonstandard grounding equipment on live lines are therefore not limited to equipment quality. They arise when an unverified assembly is treated as a protective system without confirming its fault duty, installation geometry, work-zone effect, and suitability for the actual operating state of the line. In electrical safety, a ground is not simply a cable connected to earth. It is a controlled, rated, and correctly installed protection measure whose failure can expose people and networks to the full consequences of an unintended energization or fault.