How do you test an oil burner transformer safely?

Testing an oil burner transformer requires isolating power, verifying zero voltage, and using insulated tools. A multimeter checks primary resistance and secondary continuity, while a dedicated high voltage tester or spark gap verifies output. Never touch secondary terminals during operation due to high ignition voltage. Visual inspection for cracks, carbon tracking, or oil leaks is essential. Testing should follow manufacturer instructions and local electrical safety rules to avoid shock, equipment damage, or ignition hazards.