What determines whether current will flow through a conductor?

Current flow through a conductor is determined by the presence of voltage. Voltage, or electrical potential difference, creates the force necessary to push electrons through the conductor. Without sufficient voltage, there is no driving force to move the electric charge, and therefore, current will not flow.

While Ohms represent resistance in a conductor, which affects how much current can flow for a given voltage (as described by Ohm's Law), they do not themselves cause the current to flow. Amperes measure the actual flow of electric current, but they are a result of the applied voltage overcoming resistance. Watts are a measure of power, indicating how much work is done by the electric current, yet they also rely on both voltage and amperage figures. Thus, while all these concepts are closely related in the functioning of electrical systems, voltage is the primary factor that determines the potential for current flow.