Canada Electrical Trade Practice Exam

The factor that influences how many motors can be grouped under one set of over-current devices is the ampacity of the devices. Ampacity refers to the maximum amount of current that a conductor or device can carry without overheating. When grouping motors, it is essential to ensure that the total current drawn by all the motors does not exceed the ampacity of the over-current protective devices.

Over-current devices are designed to protect circuits and equipment from excess current that can cause overheating or damage. Therefore, if multiple motors are connected to the same set of over-current devices, their combined current draw must be evaluated against the devices' rated capacity. This ensures that the protective devices will operate correctly in the event of an overload, providing adequate protection and preventing potential hazards.

Understanding the concept of ampacity is crucial for making safe and compliant electrical installations, as it directly determines how many motors or loads can be safely protected by a single set of over-current devices.