What is the maximum acceptable supply voltage tolerance for a 120 V circuit?

The maximum acceptable supply voltage tolerance for a 120 V circuit is +/-5%. This tolerance is established to ensure that electrical equipment operates efficiently and safely within its designed parameters. Operating outside this voltage range can lead to problems such as increased energy consumption, reduced performance, and potential damage to electrical components.

When the voltage is too high, devices may heat up more than normal, leading to premature failure, while too low of a voltage can cause motors to run inefficiently and appliances to function improperly. A tolerance of +/-5% allows for minor fluctuations in supply voltage due to variations in the power grid or other environmental conditions, maintaining reliability and longevity in electrical systems.

Understanding these tolerances is crucial for technicians, as adhering to voltage specifications is a fundamental aspect of ensuring safety and effectiveness in HVAC systems and other electrical installations.