Why should bonding and grounding connections be metal-to-metal and tight?

• A. To ensure a reliable, low-impedance fault path and minimize potential differences.
• B. To increase impedance on fault paths.
• C. To prevent any fault current from flowing.
• D. To keep bonding connections loose to allow movement.

Answer: (A)

Bonding and grounding connections must be metal-to-metal and tight to create a continuous, low-impedance path for any fault current. When metal surfaces are in solid contact with good pressure, contact resistance is minimized, allowing fault currents to flow quickly back to the source and keeping all connected metal parts at the same electrical potential. This rapid, low-resistance path helps protective devices detect the fault and trip promptly, reducing the risk of shock and preventing damage to equipment.

If surfaces aren’t clean and tight, coatings, paint, corrosion, or loosening fasteners raise impedance. That higher resistance can allow dangerous voltage differences to develop between bonded parts and may prevent the overcurrent device from tripping quickly enough. Loose connections are prone to arcing and can deteriorate further, compromising safety and reliability.

So the emphasis is on establishing a robust, metal-to-metal bond with secure, tight connections to ensure a reliable fault path and minimize potential differences.