Substation Technician how-to

How to Sample Transformer Oil

Oil tests reveal transformer health.

Updated By the Career Education Institute Curriculum Team
Quick answer

Oil tests reveal transformer health. In short: wear; use; flush, then complete the remaining steps below.

Step by step

  1. Wear PPE.

  2. Use clean sample containers.

  3. Flush the sample valve.

  4. Fill without air bubbles.

  5. Seal and label.

  6. Send to the lab.

Safety reminders for substation technicians

  • Follow clearance and grounding procedures
  • Wear arc-flash PPE
  • Test before you touch
  • Maintain approach distances

Substation · Transformer · Circuit breaker · Protective relay · CT · PT: see the full substation technician glossary.

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