Short answer: De-energize first, then prove it. Lockout/tagout must be carried out by employees authorized under the applicable energy-control procedure. Electrical absence-of-voltage testing must be performed by a qualified person. An apprentice must not perform either task independently without the training, authorization, qualifications, and supervision required for that specific task. A simplified learning sequence is to prepare, shut down, isolate energy sources, apply the required energy-control devices, address stored energy, and verify de-energization. This is a learning sequence, not a substitute for the electrical safety procedure required for your task.
Still trying to get into an apprenticeship? If you are preparing for an apprenticeship interview, practice explaining how you would respond to an unsafe task or an instruction you do not understand. The Texas Electrical Apprenticeship Entry Kit has 20 interview questions with a weak and a strong answer each, an 8-question mock interview and 6 timed aptitude simulations. Launch price US$49 through November 30, 2026.
Tsai Electro is an independent learning site. Not affiliated with OSHA, NFPA, TDLR or PSI. This page summarizes OSHA rules in our own words and does not reproduce NFPA 70E. It is not a lockout procedure. Follow your employer’s written energy control procedure and your supervisor’s instructions, and never work on equipment you were not trained and authorized to lock out.
Whose rules these are
- OSHA 1910.333 covers electrical safety-related work practices in general industry. It says live parts must be de-energized before work on or near them unless the employer can show that de-energizing creates greater hazards or is infeasible, with a limited exception below 50 volts to ground (OSHA 1910.333).
- OSHA 1910.147 governs hazardous-energy control during covered servicing and maintenance in general industry. Its scope excludes construction employment and electrical-hazard exposure covered by general-industry Subpart S. For applicable general-industry electrical work, see 1910.333(b)(2); for construction electrical work, see 1926.416 and 1926.417. The six steps below summarize 1910.147(d) as an educational model, not as a universal procedure or the controlling rule for every electrical task (OSHA 1910.147).
- On construction sites, OSHA 1926.417 requires deenergized circuits to be rendered inoperative and tagged at every point where they can be energized (OSHA 1926.417), and 1926.416 requires protection by deenergizing and grounding or by guarding (OSHA 1926.416).
- NFPA 70E is a consensus standard for electrical safety in the workplace that many employers build their electrical safety programs on (NFPA 70E overview). Employers must comply with applicable OSHA requirements and establish appropriate electrical safety procedures. NFPA 70E may inform those procedures, including through employer policy, contractual requirements, or other applicable adoption mechanisms. Verify which edition and requirements govern your workplace.
Texas licensing also points to NFPA 70E: TDLR requires electrician continuing education to cover electrical safety as defined in NFPA 70E (TDLR continuing education page).
The six steps, in order
As an educational comparison, OSHA 1910.147(d) lists these actions in this sequence for general-industry energy control procedures. For electrical work, your employer’s task-specific procedure and the rules in 1910.333(b)(2), 1926.416 and 1926.417 apply:
| Step | What happens |
|---|---|
| 1. Prepare for shutdown | The authorized employee knows the type and size of the energy, its hazards and how to control it |
| 2. Shut down | Turn the equipment off by its normal procedure, in an orderly way |
| 3. Isolate | Operate every energy-isolating device (breaker, disconnect, valve) so the equipment is cut off from every source |
| 4. Apply energy-control devices | Authorized employees apply the required lockout or tagout devices to the energy-isolating devices under the applicable procedure. Group lockout and tagout-only arrangements have additional requirements. |
| 5. Release stored energy | Identify and control hazardous stored or residual energy before verification. Depending on the equipment, this may require discharging capacitors, controlling stored mechanical energy, or preventing energy from reaccumulating. Only authorized and qualified personnel should perform the actions for which they have been trained, using the applicable procedure |
| 6. Verify isolation | Before starting work, confirm the equipment is isolated and de-energized |
Two rules frame the sequence:
- Notify first and last. Affected employees are told before the locks go on and after they come off (1910.147(c)(9)).
- Your lock, your key. Lock and tag removal is tightly controlled. Under OSHA 1910.147(e)(3), the employee who applied the device generally removes it, subject to a limited employer-controlled exception. For electrical work covered by 1910.333, paragraph (b)(2)(v)(C) sets specific requirements for removing locks and tags, including conditions when the applying employee is absent. Group lockout may involve additional requirements under the applicable standard and employer procedure. Never remove another person’s lock or tag unless you are specifically authorized and every applicable removal requirement has been met.
OSHA also says the employer provides the locks, tags and other hardware the procedure uses (1910.147(c)(5)(i)).
Verifying that it is dead
Under OSHA 1910.333(b)(2)(iv), a qualified person must verify that the equipment cannot be restarted and use suitable test equipment to confirm that exposed circuit elements and electrical parts are de-energized. The test must also address energized conditions caused by induced voltage or backfeed. Above 600 volts, nominal, the tester must be checked for proper operation immediately before and after the test.
A before-and-after tester check is an important electrical safety practice that many programs apply at every voltage, often called live-dead-live. Absence-of-voltage testing must be performed by a qualified person using test equipment suitable for the electrical system and its hazards, including the proper voltage rating and condition. The qualified person must follow the employer’s approved electrical safety procedure, including the required protective measures for testing potentially energized parts. The steps below are a conceptual illustration, not instructions for an unqualified apprentice to perform the test.
- A qualified person proves the tester works, using a method in the employer’s procedure (often a known live source).
- Test the circuit parts at the point of work: each conductor to each other conductor and each to ground.
- Prove the tester again with the same method.
If the tester fails either check, the “dead” reading in step 2 means nothing. Vendor summaries of the current NFPA 70E describe this before-and-after check and testing at each point of work. Read your employer’s procedure for the exact steps.
Practice: put the steps in order
You are helping replace a receptacle on a 20-ampere, 120-volt circuit in an occupied commercial building. In this hypothetical exercise, your journeyman is the qualified person who tests; as an apprentice you observe and follow the procedure. Here are the steps out of order:
- A. Check the voltage tester on a known live source.
- B. Tell the people who use that circuit that it is going down.
- C. Open the breaker.
- D. Put the lockout device, lock and tag on the breaker.
- E. Test the receptacle conductors for absence of voltage, each to each and each to ground.
- F. The qualified person identifies and confirms every energy source that could energize the circuit, using the panel schedule only as a starting reference.
- G. Check the voltage tester on the known live source again.
- H. Start the work.
Answer: F, B, C, D, A, E, G, H. This exercise tests the order of selected actions; actual work requires the full employer-approved procedure and a qualified person’s verification.
- F is preparation: you cannot control energy you have not identified.
- B comes before the lock goes on, per the notification rule.
- C shuts down and isolates.
- D applies the lock and tag.
- Stored energy: before voltage verification, the qualified person must determine whether any hazardous stored or residual energy is present and ensure it has been controlled. The exercise assumes that this assessment has been completed and no separate stored-energy action is needed. Real equipment may require additional steps before verification.
- A, E and G are the verification: tester check, test, tester check.
- Only after the qualified person confirms the circuit is de-energized and the procedure allows it does work start (H).
Check yourself: if E came before A, a dead tester could show a live circuit as dead. That is why A must come before E.
Mistakes apprentices should never make
- Trusting a breaker label without testing.
- Working under someone else’s lock, or removing someone else’s lock.
- Assuming a circuit is safe without a qualified person verifying the absence of voltage with properly checked test equipment.
- Overlooking another source of voltage, such as generator backfeed, or the hazards associated with shared or multiwire branch circuits.
- Treating a tag alone like a lock without the extra steps your procedure requires.
FAQ
What is the difference between NFPA 70E and OSHA lockout/tagout?
OSHA rules such as 1910.147, 1910.333 and 1926.417 are federal requirements. NFPA 70E is a consensus standard for workplace electrical safety that many employers use to build their electrical safety programs, including how they reach an electrically safe work condition.
What are the steps of lockout/tagout in order?
OSHA 1910.147 lists them as preparation for shutdown, equipment shutdown, isolation, applying lockout or tagout devices, releasing stored energy, and verifying isolation, in that order.
What does live-dead-live mean?
A qualified person proves the tester, tests the de-energized parts, then proves the tester again. It shows the tester was working when it read no voltage.
Can an apprentice apply a lockout?
An apprentice may participate in lockout/tagout only to the extent permitted by their training, authorization, supervision, and the applicable energy-control procedure. Authorization to participate in lockout does not automatically qualify someone to perform electrical absence-of-voltage testing. That testing must be performed by a qualified person. Device application and removal must follow the applicable OSHA requirements, including any group-lockout provisions.
Sources checked October 2026
- OSHA 1910.333, selection and use of work practices: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.333
- OSHA 1910.147, control of hazardous energy: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.147
- OSHA 1926.417, lockout and tagging of circuits: https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.417
- OSHA 1926.416, electrical safety requirements: https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.416
- NFPA, learn more about NFPA 70E: https://www.nfpa.org/education-and-research/electrical/learn-more-about-nfpa-70e
- TDLR electrician continuing education page: https://www.tdlr.texas.gov/electricians/elecce.htm
- Vendor summary of NFPA 70E voltage verification (secondary): https://www.mscdirect.com/betterMRO/safety/keeping-changing-electrical-safety-standards-2024-nfpa-70e
