When replacing or repairing any electrical components, always verify that the:

• A. Power source is disconnected and locked out.
• B. System is fully charged.
• C. The compressor is off.
• D. Defrost timer is set.

Answer: (A)

Before replacing or repairing electrical components, you must ensure there is no energy available to the circuit. The only reliable way to do that is to disconnect the power and apply a lockout device with a tag, so the circuit cannot be re-energized while you work. This creates a verifiable state of zero energy and prevents accidental startup or energization from other sources. Relying on the system simply being off, or on the compressor or a defrost timer, does not guarantee safety because there can be other energy paths or stored energy that could energize the circuit again. Verifying isolation and applying lockout/tagout is the essential protection for electrical servicing.