A resistance of _____ ohms or less must be obtained when accomplishing a static grounding/bonding reel inspection.

• A. 5 ohms or less
• B. 8 ohms or less
• C. 12 ohms or less
• D. 20 ohms or less

Answer: (C)

The main idea is to ensure a low-impedance path to dissipate static quickly. In explosive safety work, a grounding/bonding reel must create a continuous, low-resistance connection between the equipment and ground so static charges don’t build up and cause a spark.

Twelve ohms or less is used as the threshold because it provides a practical, achievable limit that still offers rapid discharge of static under field conditions. If the resistance is higher, static energy can linger on the equipment or conductors, increasing the chance of a spark during handling, connection, or disconnection. While aiming for an even lower value would be safer, twelve ohms represents a workable balance between safety and the realities of maintenance in the field—where dirt, moisture, and contact quality can push resistance up.

During inspection, check all parts of the grounding path: the reel, clamps, connectors, and conductors. Clean and tighten connections, replace any corroded or damaged components, and re-test to confirm the resistance is at or below twelve ohms. If it cannot be brought down to that level, the ground path must be repaired or replaced before proceeding.