What is the maximum bonding jumper resistance expressed in milliohms?

What is the maximum bonding jumper resistance expressed in milliohms?

• A. 1 milliohm
• B. 10 milliohms
• C. 3 milliohms
• D. 5 milliohms

Answer: (C)

Bonding jumpers must provide an almost instantaneous, low-impedance path to keep all metallic parts at the same electrical potential. This minimizes voltage differences that could cause static discharge or sparks, which is especially important in areas with flammable vapors. The specified maximum is 3 milliohms, or 0.003 ohms. Keeping the resistance at or below this value ensures that even with fault or bonding currents, the voltage drop across the jumper remains very small, reducing the risk of arcing. Values higher than this would allow larger potential differences between bonded parts, increasing safety risks. A value like 1 milliohm is stricter than required, but the standard allows up to 3 milliohms.

Bonding jumpers must provide an almost instantaneous, low-impedance path to keep all metallic parts at the same electrical potential. This minimizes voltage differences that could cause static discharge or sparks, which is especially important in areas with flammable vapors. The specified maximum is 3 milliohms, or 0.003 ohms. Keeping the resistance at or below this value ensures that even with fault or bonding currents, the voltage drop across the jumper remains very small, reducing the risk of arcing. Values higher than this would allow larger potential differences between bonded parts, increasing safety risks. A value like 1 milliohm is stricter than required, but the standard allows up to 3 milliohms.