In brief
The five rules of dead working are, in order: disconnect, secure against reconnection, verify absence of voltage, earth and short-circuit, protect against adjacent live parts. The rules are applied in order and reversed in the opposite order when the work is finished. The Regulation on Work Equipment also requires maintenance to be carried out with the energy supply disconnected and movement stopped; the procedure must be written, personal locks must be used and those doing electrical maintenance must be certified.
What are the 5 electrical safety rules and where do they come from?
The 5 electrical safety rules are the internationally accepted foundation of dead working and are set out in TS EN 50110-1, the standard on the operation of electrical installations. The rules are:
- Disconnect (isolate the installation).
- Secure against reconnection.
- Verify that the installation is dead.
- Earth and short-circuit.
- Provide protection against adjacent live parts.
The order matters: earthing is not done before the absence of voltage has been verified, and measurement does not start before a lock is fitted. When the work is finished, the rules are reversed in the opposite order.
On the legislation side, Annex I of the Regulation on Health and Safety Requirements for the Use of Work Equipment sets three basic principles: maintenance work is carried out with the equipment switched off, the energy supply disconnected and all movement stopped (2.13); the means of isolating energy sources are clearly visible and identifiable, and reconnecting the equipment to the energy supply must not create a hazard for employees (2.14); all work equipment protects employees from direct or indirect electrical contact (2.19). The five rules are what these principles mean on site.
Rule 1: Disconnect
The first step is to separate the installation or machine to be worked on from all energy sources. The most common mistake on site is stopping the machine with the control button or contactor and counting it as "switched off". The control circuit does not isolate energy; energy is isolated by opening an isolator or switch, or by removing a fuse.
Before isolating, list all sources:
- The main supply and any second supply circuit
- Uninterruptible power supplies and generators
- Capacitor banks and the DC links of frequency converters; they can hold a charge for some time after isolation
- The possibility of back-feed: a motor being turned mechanically, lines connected in parallel, rooftop solar systems
- Non-electrical energy in the machine: hydraulic pressure, compressed air, springs, parts that can descend under gravity
At sites with a rooftop solar system, pay special attention to this source: even if the grid side is disconnected, the panels keep generating voltage on the DC side as long as there is daylight. This system should be shown separately on the single-line diagram and added to the energy isolation procedure.
Rule 2: Secure against reconnection
A switch that has been isolated being turned back on by someone unaware of the work is the classic electrical accident scenario. The way to prevent this is lockout and tagout:
- Personal lock: Each employee fits their own padlock and keeps the key. One lock, one person, one key.
- Multiple lockout hasp: If more than one person is working, each fits their own lock to the hasp; the switch cannot be turned on until the last lock is removed.
- Tag: Next to the lock, it is written who locked it, for which job and on what date. A tag alone does not replace a lock.
- For fuses: A removed fuse is kept with the employee; a blanking cover or lockable cover is fitted to the holder.
Rule 3: Verify absence of voltage
Do not assume something is "isolated" without measuring that there is no voltage. For the verification to be reliable, use the "test, measure, test again" method: first try the measuring instrument on a known live source, then measure at the point to be worked on, then try the instrument again on the known source. This prevents a faulty instrument from misleading you.
Measurement is done between all phases and between each phase and neutral and earth. The measuring instrument used must suit the voltage level of the installation and the measurement category; if the category of the instrument in the hands of an electrician measuring at a panel incomer is not suitable for that point, they put themselves in danger during the measurement.
Rule 4: Earth and short-circuit
Earthing and short-circuiting protect the work point against accidental energisation or induced voltage. At high voltage installations this rule is always applied; at low voltage, it is applied where there is a risk of back-feed, induction or accidental energisation. Tie this decision to a written procedure; do not leave it to personal preference on site.
The order of application is: the earthing device is connected to the earth side first, then to the conductors; when removing, the reverse order is followed. Earthing is applied close enough to be visible from the work point and, if possible, between the work point and the energy source.
Rule 5: Protect against adjacent live parts
Even if the section being worked on is dead, the busbar, terminal or line right next to it may be live. These parts are covered with insulating sheets, barriers or screens, and the work area is bounded with tape and signs. If work is being done on a partly energised panel, which compartment remains live is written on the panel.
Site procedure: isolating and restoring energy
When the five rules are not turned into a written procedure, practice varies from person to person. An example flow for a production facility:
| Step | Task | Who? | Record |
|---|---|---|---|
| 1 | Defining the job, the affected equipment and all energy sources | Maintenance lead | Permit to work form |
| 2 | Informing the production supervisor, stopping the machine in the normal way | Operator | Permit to work form |
| 3 | Isolation: opening the switch or isolator, removing the fuse | Authorised electrician | Lock list |
| 4 | Personal lock and tag; releasing other forms of energy | Each employee | Lock list |
| 5 | Verifying absence of voltage with the test-measure-test method | Authorised electrician | Permit to work form |
| 6 | Earthing and short-circuiting if required | Authorised electrician | Permit to work form |
| 7 | Covering adjacent live parts, marking the area | Authorised electrician | Photo |
| 8 | Carrying out the work | Team | — |
| 9 | Restoration: collecting tools and materials, headcount, refitting guards | Team leader | Permit to work form |
| 10 | Removing the earthing, locks removed by their owners, energy restored | Authorised electrician | Permit to work closure |
To see whether the procedure is staying on paper, look for the answers to these questions on site rounds:
- Do panels and main switches have up-to-date labels showing which machine they supply?
- Does every maintenance employee have a lock and tag registered in their name, or are locks taken from a shared box?
- Are voltage testers calibrated and in good condition, and are their probe leads damaged?
- Do the permit to work forms closed in the last month state who verified the absence of voltage?
- How are locks for ongoing work handed over at shift change?
The last question is particularly important: at a shift change, between an employee removing their lock and leaving and the incoming employee fitting their own lock, the switch can be unprotected for a few minutes. Make it a rule in the handover that the new lock is fitted before the old one is removed.
For jobs where energy isolation affects more than one team, see our permit to work system guide, and for protective arrangements on machines, our machine guards guide.
Competence, certification and periodic inspection
Electrical maintenance is not work anyone can do. Row 75 of the Annex 1 list of the regulation on vocational training for employees in hazardous and very hazardous work is "electricity generation, transmission and distribution work, electrical maintenance and repair work". An employee doing this work must hold a vocational training certificate appropriate to the work before being employed; details are in our vocational training certificate guide.
The installation itself is also inspected. Under Annex III of the Regulation on Work Equipment, the indoor electrical installation and earthing, lightning protection installations, generators, transformers and accumulators are subject to periodic inspection at most once a year. These inspections are carried out by competent electrical engineers, electrical-electronic engineers, technical teachers who graduated from electrical education departments, and electrical technicians or senior technicians; for installations of 1 kV and below, competent electronic engineers may also carry out inspections. For details, see our periodic inspection intervals guide. Non-conformities in the earthing report also directly affect the application of the five rules: in an installation with faulty earthing, a fault to the casing means extra risk for the person doing maintenance.
On the personal protective equipment side, insulating gloves, insulated tools, face shields and suitable workwear are chosen according to the voltage level and arc risk of the work. This choice is part of the risk assessment, and personal protective equipment does not replace the five rules.
For businesses in Bursa and the surrounding provinces, under our OHS specialist service we write the energy isolation procedure for your facility, identify lockout points on site and monitor implementation during periodic site rounds. For risks specific to the metal and machinery sector, see our metal and machinery page.
Frequently Asked Questions
What does dead working mean?
It is work in which the part of the installation to be worked on has been made dead by applying the five safety rules and the absence of voltage has been verified. Simply stopping the machine or switching off the control circuit does not count as dead working.
Is earthing mandatory for every job?
At high voltage installations, earthing and short-circuiting are always applied. At low voltage, they are applied where there is a risk of back-feed, induction or accidental energisation. Specify in the written procedure which jobs require it.
Does attaching a tag replace a lock?
No. A tag shows who locked it and why; it does not physically prevent the switch from being turned on. If there is an isolation point that cannot be locked, an additional measure should be taken, such as removing the fuse or fitting a lockable cover.
How often is the electrical installation periodically inspected?
Under Annex III of the Regulation on Work Equipment, the indoor electrical installation and earthing are inspected by competent persons at most once a year. After a significant change or damage, the inspection should be done without waiting.
A certified specialist matched to your hazard class: site inspections, approved logbook, training plan, annual plan and report follow-up.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.