LOTOTO stands for lockout, tagout, tryout. It is lockout tagout (LOTO) with the final check, proving the equipment is dead, written into the name. That check is where electrical work most often goes wrong: of the electrical accidents to qualified electricians reported in Germany in 2021 that broke one of the five safety rules, 49.6% broke the rule to verify the absence of voltage.[1]
This post answers three questions:
- What does LOTOTO add to LOTO?
- What counts as a valid tryout?
- Which name should your procedures and training use?
Part 1: What Does LOTOTO Mean?
LOTOTO means lockout, tagout, tryout. After every energy source is isolated, locked and tagged, the authorised person tries to start the equipment, or tests it, to prove that no hazardous energy remains. Only then does work begin. LOTO requires the same check. LOTOTO puts it in the name.
The tryout is done by the person who will do the work, at each isolation point, every time.
In the DACH region and France, the same step sits inside the national rules under other names (Part 4).
Part 2: LOTO vs LOTOTO, Step by Step
Both follow the same steps. The only difference is what the name spells out.
| Step | What happens | Named in "LOTO" | Named in "LOTOTO" |
|---|---|---|---|
| 1. Identify | List every energy source: electrical, pneumatic, hydraulic, thermal, chemical, gravity, stored mechanical | No | No |
| 2. Shut down | Stop the equipment with its normal controls | No | No |
| 3. Isolate | Open the breaker, close the valve, disconnect the supply | No | No |
| 4. Lock | Fit a lockout device and a personal padlock to each isolation point | Yes (lockout) | Yes |
| 5. Tag | Attach a tag: who locked it, when and why | Yes (tagout) | Yes |
| 6. Release stored energy | Bleed pressure, discharge capacitors, block parts that can fall | No | No |
| 7. Try out | Prove zero energy: attempt a start, test for voltage, read the gauges | No, but required | Yes (tryout) |
A typical electrical isolation: a dustproof LOTO padlock with a 38 mm steel shackle on a circuit breaker lockout, a safety hasp with six lock points so each worker can add their own lock, and a lockout tag on the motor control panel. Most sites keep these devices together in lockout tagout kits, one per crew or machine. For the full sequence, see the 6 (and more) steps of lockout tagout.
Part 3: What a Valid Tryout Involves
The tryout has to prove that steps 3 to 6 worked. Looking at the locks proves nothing. The test itself is work on equipment that may still be live, so it needs the same precautions.[2]
Try to start it
Clear the area, then press the normal start controls. If the machine has more than one control station, try each one. Nothing should move. Return every control to off before work begins, so the machine cannot start the moment the locks come off.
Test for absence of voltage
On electrical isolations, test every conductor at the point of work with a voltage tester made for the job, and check that the tester works before and after the test.[1] French guidance is explicit: a multimeter or test screwdriver does not count.[2]
Check stored energy
Read the pressure gauges, open the bleed valves, and confirm that raised parts are blocked. An electrical test does not catch stored energy.
Get a second check
On complex isolations, a second authorised person checks each isolation point and tag before work starts.
Best Practice: Write the tryout into every machine procedure as its own numbered step, with the method and the expected result: "Press START at the local panel: no movement." "Test L1, L2, L3 and N at the terminal box: 0 V." Our guide to writing a LOTOTO procedure shows the format.
Part 4: The Tryout Under EU and Swiss Rules
European rules don't use the word "tryout", but each of them requires the step.
- Machinery, EN ISO 14118:2017: defines isolation and energy dissipation as four actions: isolate, lock, dissipate stored energy, and verify, for example by measuring, that the first three worked (clause 3.3).[3]
- Electrical work, EN 50110-1 (DIN VDE 0105-100 in Germany): the five safety rules. Rule 3, "verify the absence of voltage", is the tryout.[1]
- Switzerland: Suva's "5 + 5 vital rules" require electricians to work de-energised according to the five safety rules.[4]
- France: consignation ends with verification. For electrical work, that is the vérification d'absence de tension (VAT) on every conductor, including the neutral.[2]
- US, for comparison: OSHA 29 CFR 1910.147(d)(6) requires the authorised employee to verify isolation and de-energisation before work starts.[5]
Why it matters: in several European countries, around 10-15% of fatal workplace accidents in 2006 were related to maintenance.[6]
Part 5: LOTO or LOTOTO: Which Name Should Your Site Use?
Either. The step matters more than the name. A site that says LOTO and tests every isolation is safer than a site that says LOTOTO and skips the test on short jobs.
Use the term your workforce and contractors already know, define it once in your procedure, and make the tryout a numbered step with a sign-off. On shared jobs, agree the term and the tryout method with contractors before work starts. Removing the locks afterwards needs the same care, in reverse order.
Part 6: Where The Lock Box Fits
A tryout only proves something if every isolation point is locked first. Our lockout kits range from electrical and circuit breaker kits to combined valve and electrical kits, plus bags and pouches for a kit you put together yourself. For electrical work, see which electrical lockout kit you need for LOTOTO.
On jobs with many isolation points and several workers, a group lockbox, often called a lockout box, holds the keys to the isolation locks, and each worker puts a personal lock on the box.
Our free electrical isolation record puts the tryout on record: each of the five safety rules is signed in order, including the check for absence of voltage (PDF, Word or Excel).
Need a Kit That Matches Your Procedure?
Contact The Lock Box with the energy sources on your machines, and we will propose a kit for each procedure.
References
- BG ETEM / DGUV. DGUV Information 203-001: Sicherheit bei Arbeiten an elektrischen Anlagen, pp. 16 and 20 (status 05/2022). https://medien.
bgetem. de/ medienportal/ artikel/ TUIwMDY- - INRS. ED 6109: Consignations et déconsignations, 3rd edition, October 2020. https://www.
inrs. fr/ dam/ inrs/ CataloguePapier/ ED/ TI- ED- 6109. pdf - ISO. ISO 14118:2017: Safety of machinery, Prevention of unexpected start-up, clause 3.3. https://www.
iso. org/ standard/ 66460. html - Suva. 5 + 5 lebenswichtige Regeln im Umgang mit Elektrizität (84042.D). https://www.
suva. ch/ 84042. d - OSHA. 29 CFR 1910.147: The control of hazardous energy (lockout/tagout), paragraph (d)(6). https://www.
osha. gov/ laws- regs/ regulations/ standardnumber/ 1910/ 1910. 147 - EU-OSHA. Maintenance and Occupational Safety and Health: A statistical picture, p. 41 (2010). https://osha.
europa. eu/ sites/ default/ files/ maintenance_ OSH_ statistics. pdf