Industrial Automation

Panel Door Earth Bonding Procedure: Ensuring Safety and Reliability

Why is it important to use protective bonding?

  • To ensure the safety of people, property, and equipment, protective bonding is required.
  • One of its key functions is to protect against electric shocks. It accomplishes this by allowing electrical faults to flow away from humans and equipment in a safe manner.
  • Electrical fires are considerably reduced by protective bonding. It reduces overheating and potential ignition sources by swiftly redirecting fault currents.
  • It is critical in protecting electrical and electronic equipment. 
  • This safeguard is especially crucial for avoiding damage caused by voltage fluctuations, power surges, and electromagnetic interference.
  • Protective bonding dissipates electrostatic charges securely in places where electrostatic charges can build (e.g., industrial facilities). This decreases the possibility of damaging sensitive electronic components due to sudden and potentially destructive discharges.
  • Protective bonding assures that all electrical system components have the same electrical potential. This reduces potential differences and eliminates electrical interference, ensuring that equipment functions properly.
  • One of the primary reasons for using protective bonding is to ensure compliance with safety standards and regulations. To satisfy these norms, several countries and areas have special requirements.
  • Maintaining the integrity of electrical systems requires proper protective bonding. It decreases the possibility of system failures and downtime, which can be costly and inconvenient.
  • In the event of an electrical emergency or maintenance work, protective bonding keeps personnel safe from electrical risks. It enables the safe deactivation of systems.
Panel Door Earth Bonding Procedure: Ensuring Safety and Reliability 1

What is the difference between Earthing and Bonding?

Panel Door Earth Bonding Procedure: Ensuring Safety and Reliability 2
AspectEarthing (Grounding)Bonding
PurposeEnsure safety by providing a path for fault currents to dissipate into the ground.Ensure that conductive components within a system are at the same electrical potential.
Safety FocusPrevent electric shock hazards.Prevent differences in electrical potential between conductive parts to reduce electrical hazards.
Electrical PotentialEstablish a reference point for electrical potential concerning the Earth.Ensure that all conductive components have the same electrical potential.
Protection Against LightningProtect structures and electrical systems from lightning strikes by providing a safe path for lightning currents to travel into the ground.Not primarily focused on lightning protection, although it plays a role in reducing potential differences that can lead to lightning-induced damage.
ComplianceMany electrical safety standards and codes mandate proper earthing practices to ensure compliance with safety regulations.Bonding practices may also be governed by standards, but they are primarily for maintaining equipment safety and operation rather than safety standards compliance.
Interference and Equipment ProtectionWhile it provides some level of equipment protection by diverting fault currents, its primary focus is on safety.Prevents potential differences within a system, reducing the risk of electrical interference, equipment damage, and equipment malfunctions.
  • Earthing (grounding) is primarily concerned with safety and establishing a reference point for electrical potential, whereas bonding is concerned with maintaining the same electrical potential between various conductive parts in order to prevent potential differences, reduce electrical hazards, and ensure proper equipment operation. 
  • Both techniques are necessary for electrical safety, although they serve different functions. 

When is Bonding required?

  • A conductive metal component needs to be linked to ground whenever there’s a chance it could become electrified. 
  • This covers junction boxes, raceways, cable trays, and enclosures for service equipment in addition to conduit for wires and cables. 
  • Non-electrical components that are close to our electrical system, such as handrails, stairs, and gas and water pipes, must also be bonded. 
  • This is particularly crucial in locations where people may come into close touch with exposed metal components or where the presence of potentially explosive gasses or dusts is possible. 
  • Your local standards and regulations will specify exactly what you need to bond, however it is usually preferable to bond if you are unsure.

Panel Door Earth Bonding Procedure 

  • Panel door earth bonding is an important aspect of assuring the safety and functionality of electrical systems. 
  • Here’s a more extensive step-by-step explanation of the procedure:

Determine Grounding Points

  • To begin, locate the grounding points on the electrical panel door. These may include manufacturer-supplied bonding screws, terminals, or specialized grounding locations.

Examine the Panel Door

  • Examine the panel door to ensure that it has grounding provisions. Ascertain that it is in good condition and without of any damage that could interfere with the bonding procedure.

Choose Grounding Conductors

  • Select appropriate grounding conductors for the job. Because of their conductivity and corrosion resistance, copper and aluminum conductors are often utilized.

Prepare the grounding conductors

  • Grounding conductors must be cut and prepared to the desired length. Check that the ends are clean and free of oxidation or impurities that could interfere with a good electrical connection.

Join the Grounding Conductor

  • Using the grounding conductors, make a low-resistance connection between the panel door and the designated grounding points. Use appropriate connectors, lugs, or clamps to secure the conductors.

Make use of Earth Bonding Washers

  • Improve the bonding connection by using appropriate earth bonding washers. 
  • The type of washer used, such as external or internal tooth star washers, serrated washers, integrated washers, or wedge lock washers, is determined by the panel door’s specific design and requirements.

Examine for Continuity

  • Examine the electrical connection between the panel door and the grounding system. 
  • To ensure a reliable connection, use a continuity tester. This step is critical to ensuring that the panel door is securely fastened to the ground.

Shielded Cable Grounding

  • If the panel contains shielded cables for analog or digital instruments and field wiring, make sure the shields are linked to earth
  • This method helps in the prevention of electromagnetic interference and ensures adequate shielding.

Earthing Cable Continuity

  • Examine the system’s earthing wires for continuity. Follow the cables from the separate control panels to the central earth busbar and then to the earth pits
  • Any interruption in continuity can jeopardize the overall efficacy of the earthing system.

Earth Bonding of Field Instruments

  • Earth the bodies of field instruments within the panel properly. This ensures that potential differences are minimized while maintaining safe and effective operation.

Preventing Ground Loops

  • Take steps to avoid the formation of ground loops within the electrical panel. 
  • Ground loop currents can interfere with field instrument performance, potentially resulting in inaccuracies or failures.

Busbar Design and Cable Selection

  • Check that the busbar design in the electrical panel is acceptable for the purpose. 
  • Choose adequate earthing cables by taking into consideration variables such as current carrying capacity and environmental conditions.

Inspection and testing on a regular basis

  • Implement a routine inspection and testing system to ensure that the panel door earth bonding is successful. 
  • Periodic checks and resistance measurements can ensure that low-resistance connections are kept and that the system stays safe and reliable.

Importance of Earth Bonding Washers

Panel Door Earth Bonding Procedure: Ensuring Safety and Reliability 3
  • Earth bonding washers are essential for establishing a low-resistance interface between the grounding system and conductive parts like panel doors. 
  • These washers increase the surface contact between surfaces, which aids in the establishment of a safe and reliable electrical connection. 

Can star washers be used for bonding?

  • The following are some ways that earth bonding washers support good bonding:

Low-Resistance Path

  • Earth bonding washers are designed with specific features like serrations, external/internal teeth, or wedge locks that penetrate through the surface coatings, oxides, and contaminants on the metal parts. 
  • This penetration ensures excellent electrical contact between the washer, the conductive component (e.g., panel door), and the grounding system.

Surface Enhancement

  • The serrations, teeth, or wedges on the washers create multiple contact points, increasing the contact area between the washer and the surfaces it connects. 
  • This enhanced surface contact reduces electrical resistance, allowing current to flow easily.

Improved Grounding

  • By reducing resistance, earth bonding washers enhance the efficiency of the grounding system. 
  • They help ensure that fault currents are rapidly and safely directed to the ground, minimizing the risk of electric shock, fires, and equipment damage.

Corrosion Mitigation

  • Earth bonding washers also help mitigate corrosion issues. 
  • By providing a continuous, low-resistance connection, they minimize the chances of localized corrosion and help maintain the long-term effectiveness of the bonding connection.

How does a star washer work?

Secure Attachment

  • Earth bonding washers are used in conjunction with suitable fasteners like bolts, screws, or studs to ensure a secure attachment between the panel door and the grounding system. 
  • This attachment is essential for maintaining the bonding connection over time, even in dynamic or vibration-prone environments.


  • These washers offer a consistent and reliable method for achieving low-resistance connections. 
  • Regardless of the condition or material of the surfaces being bonded, earth bonding washers help maintain uniformity in electrical potential.

What are the different types of star washers?


  • Earth bonding washers are available in various types and sizes to suit different applications and environmental conditions. 
  • Whether it’s external/internal tooth star washers, serrated washers, integrated washers, or wedge lock washers, they can be chosen based on specific needs.

Sundareswaran Iyalunaidu

With over 24 years of dedicated experience, I am a seasoned professional specializing in the commissioning, maintenance, and installation of Electrical, Instrumentation and Control systems. My expertise extends across a spectrum of industries, including Power stations, Oil and Gas, Aluminium, Utilities, Steel and Continuous process industries. Tweet me @sundareshinfohe

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