Technical Narrative: De-Energization of Medium Voltage Switchgear and Application of Lockout/Tagout

Technical Narrative: De-Energization of Medium Voltage Switchgear and Application of Lockout/Tagout

1. Purpose

This procedure outlines the safe and systematic de-energization of Medium Voltage (MV) switchgear (typically 5kV to 38kV), including the draw-out of circuit breakers and the application of Lockout/Tagout (LOTO) to ensure personnel safety during inspection, maintenance, or repair.

2. Scope

Applies to all authorized electrical workers and technicians working on or near MV switchgear in substations, power distribution centers, or industrial settings.

3. Required PPE and Tools

Category-rated arc-flash PPE (as per arc flash study results)

Voltage-rated gloves and tools

Face shield and arc-rated hood

Test instruments (live-dead-live method)

Lockout devices and tags

Draw-out racking handle or motorized racking tool

Danger signs or barriers

4. Pre-Job Requirements

Complete a Job Safety Analysis (JSA) or Job Hazard Analysis (JHA)

Review and approve switching plan by a qualified supervisor

Confirm that a one-line diagram is up to date

Notify affected personnel

Obtain work permit (if required)

5. Step-by-Step Procedure

A. Isolation and De-Energization of MV Switchgear

Identify the Equipment:

Confirm the exact switchgear line-up and the breaker (feeder or main) to be de-energized.

Verify the load and source side using the one-line diagram.

Shutdown Load:

Shut down or transfer load to an alternate source, if applicable.

Confirm shutdown with operations/control room.

Open Circuit Breaker:

Open the breaker remotely (if possible) or locally at the switchgear panel using the control switch.

Confirm Breaker Status:

Verify the "Open" indicator.

Confirm no fault or trip indication exists that may affect safety.

Verify Zero Voltage:

Apply the Live-Dead-Live test method with a properly rated voltage detector:

Test detector on a known live source (Live)

Test the circuit terminals for absence of voltage (Dead)

Retest the detector on the live source (Live)

Grounding (if applicable):

Apply temporary grounding devices on load-side busbars or cables using grounding rods and clamps with a visible means of connection.

B. Draw-Out of the Circuit Breaker

Ensure Breaker is Open and Test Confirmed:

Visually confirm OPEN position.

Confirm voltage absence on both line and load side.

Use Proper Tools:

Insert racking handle or use motorized racking tool (as per OEM instruction).

Draw Out Breaker to Test Position:

Slowly rotate or operate the racking tool to move the breaker to the TEST position.

Listen for clicks or detents to confirm positioning.

Move to DISCONNECTED Position:

Continue to rack out the breaker fully to the DISCONNECTED or REMOVE position.

Lock racking mechanism if available.

Physically Remove Breaker (if required):

Unlock and pull out the breaker from the switchgear cubicle.

Place it in a designated, grounded maintenance cradle.

C. Lockout/Tagout (LOTO) Application

Apply Lockout Device:

Install a LOTO hasp and padlock(s) on the breaker compartment door or racking mechanism to prevent re-insertion or operation.

Use multi-lock hasps if multiple workers are involved.

Attach Tagout:

Attach durable, weather-resistant LOTO tag with:

Name

Date

Contact info

Reason for lockout

Verify Lockout:

Attempt to operate breaker control switch (confirm inoperative).

Reconfirm absence of voltage at the point of work before proceeding.

Document:

Record all LOTO information in the LOTO log or control center.

Cross-reference with the electrical permit and JSA.

6. Restoration After Work

Inspect and Clear Area:

Ensure tools and personnel are cleared.

Remove temporary grounds (if applied).

Confirm that all work is complete.

Remove Personal Locks and Tags:

Each worker removes their own lock and tag after signing off.

Reinstall Breaker (if removed):

Insert and rack breaker to TEST then CONNECTED position.

Confirm all interlocks reset properly.

Re-energize:

Notify control room or operations.

Close the breaker and monitor load pickup.

Document Completion:

Finalize all logs, permits, and control room records.

7. Safety Notes

Always treat MV equipment as energized unless proven otherwise.

Never rely solely on control indicators; test with certified instruments.

Only qualified persons trained in MV systems should perform this work.

8. Reference Standards

NFPA 70E – Standard for Electrical Safety in the Workplace

OSHA 1910.269 – Electric Power Generation, Transmission, and Distribution