Which of the following options is NOT an acceptable conductor for bonding jumpers?

The reasoning behind identifying steel as not being an acceptable conductor for bonding jumpers is centered on the objectives of bonding itself—primarily to ensure electrical continuity and sufficient conductivity to prevent hazards such as electric shock or fire.

Copper and aluminum are widely recognized as excellent conductors; thus, they are commonly used for electrical applications, including bonding jumpers. Copper, with its low resistance and high conductivity, is often the preferred choice. Aluminum, while slightly higher in resistance compared to copper, is still an effective conductor and is also lighter and more cost-effective.

Corrosion-resistant materials can also be acceptable for use in bonding jumpers, provided they maintain adequate conductivity and durability even in adverse conditions. Material selection is crucial in bonding applications, as the goal is to ensure reliable electrical performance over time.

In contrast, while steel may be used in various electrical installations, it is generally not favored for bonding jumpers due to its lower conductivity relative to copper and aluminum, as well as its susceptibility to rust and corrosion when not properly treated. Therefore, the properties of steel do not meet the stringent requirements for effective bonding, which is why it is considered not acceptable in this context.