EXTRACT: Types of procedures

As indicated in the technical standard CEI 11-27, the procedures are divided into 3 main types:

a. OPERATIONAL PROCEDURES

b. WORK PROCEDURES

c. MAINTENANCE PROCEDURES

A. Operating maneuvers

The operating maneuvers are of two types:

1. Operations intended to modify the electrical state of a system by means of components or equipment, connections, disconnections for starting or stopping electrical appliances designed to be used without risk as far as technically possible
2. Manoeuvres for putting equipment out of service or back into service for work on the systems.

Type of operation: Decommissioning before work with the power off or recommissioning after the same

Employee: PES or PAV

Emergency: PES or PAV

Other maneuvers: Persons trained and authorized by RI

A1. Plant decommissioning

1. Section off the part of the system you are working on.
2. Take measures against the inadvertent re-closure of disconnect devices.
3. Make sure the system is off.
4. Earth and short-circuit the disconnected parts in HV and MV and, where required, also in LV.
5. Provide protection for any adjacent live parts.

In low and extra-low voltage systems, earthing and short-circuiting are not necessary, except when there is a risk that the system will be energized, for example:

• on overhead power lines intersected by other lines or electrically influenced;

if there are uncertainties in the correct identification of all points of possible power supply to the live parts or in the effectiveness of the measures adopted to avoid inadvertent re-closure of the disconnecting devices.

When working on overhead lines (in bare conductors or cables) with a nominal voltage of up to 1000 V AC, all conductors must be grounded as close as possible to the workstation, including the neutral conductor and control and switching conductors, for example, on mixed overhead street lighting lines. In any case, all conductors specified above must be grounded and short-circuited.

A2.Functional controls

Functional checks must be performed by “measurements” of physical data within electrical systems.

Measurements in the presence of electrical risk must be carried out only by PES or PAV or, excluding measurements in live work, by PEC only if supervised by PES or PAV.

When taking measurements on electrical systems, suitable and safe measuring instruments must be used, manufactured in compliance with specific product standards. These instruments must be checked before use and, if necessary, after use.

Type measure 1

- The open switchboard has a degree of protection towards active parts ≥ IPXXB.

- Taking into account the type of probes used (size and shape of the bare contact tip) and the distance of the active parts from each other and from the masses, there is no risk of accidental contact or accidental short circuit.

PES supervision is not required, insulating gloves and short-circuit protection visor are not required.

Type measure 2

- The open switchboard has a degree of protection towards active parts < IPXXB.

- Taking into account the type of probes used (size and shape of the bare contact tip) and the distance of the active parts from each other and from the masses, there is a risk of accidental contact but there is no risk of accidental short circuit.

The measurement must be carried out by PES or PAV suitable for working under voltage, equipped with insulating gloves, but without a visor for protection against short circuits.

Type measure 3

- The open panel has protection against active parts < IPXXB
- Taking into account the type of test leads used (size and shape of the bare contact tip) and the distance between the live parts and the ground, there is no risk of accidental short circuits. There is a risk of accidental contact with nearby accessible live parts (as an alternative to insulating gloves, the live parts must be made inaccessible with protection, such as an insulating sheet).

Type measure 4

- The open switchboard has a degree of protection towards active parts < IPXXB.

- Taking into account the type of test leads used (size and shape of the bare contact tip) and the distance of the live parts from each other and from the masses, there is a risk of accidental contact and accidental short circuit.

The measurement must be carried out by PES or PAV suitable for working under voltage, equipped with insulating gloves, a visor to protect against short circuits, a helmet and suitable clothing.

A3. Evidence

Tests include all operations intended to check the functioning or electrical, mechanical or thermal state of an electrical system.

The tests must be carried out by PES or PAV (if necessary, with suitability for working under LV voltage) or by PEC only if under the supervision of PES or PAV or the supervision of PES with regards to work without voltage or in the proximity of live parts.

Tests with external power source

• Disconnect the system from all sources of possible normal power supply.
• Make sure that the system cannot be re-energized from any power source other than the external one in use.
• Take all necessary safety measures against electrical hazards for all personnel present.
• Ensure that the separation points have adequate insulation characteristics to withstand the simultaneous application of the test voltage on one side and the operating voltage on the other.

A4.Inspection

Verification procedure

Visual examination.

Inspections must be performed by PES or PAV with experience inspecting similar (already in operation) systems. Inspections must be performed with suitable equipment to prevent hazards, also taking into account, if necessary, the limitations imposed by the presence of live parts.

Inspection results must be recorded. Appropriate corrective actions must be taken where necessary and the results recorded.

BWorking procedures

B1. Planning

The PL must notify the RI of the nature, location and impact on the electrical system in relation to the work to be carried out.

RI authorizes PL to begin work

B2.Specific requirements regarding atmospheric conditions

When working under voltage, outdoors or indoors, in the event of weather conditions that limit visibility or reduce insulating properties, the PL is left to assess whether it is necessary to suspend the work itself.

In such circumstances, the PL must take all necessary measures to leave the plant and equipment in a safe state, including with respect to third parties; personnel must leave the workplace in a safe manner.

B3. Requirements in case of induction or transfer of earth potential

Earth connections at appropriate intervals to reduce the potential between conductors and earth to a safe level.

Equipotential connections in the workplace to avoid the possibility of operators entering an induction loop.

B4. Requirements for outdoor work

Conditions under which outdoor work is prohibited

• In case of rain or snow.
• In case of thunderstorms.
• In the presence of strong winds.
• With low temperatures.
• With poor visibility.




B5. Requirements for interior work

When working indoors, weather conditions do not need to be considered if the installation is powered by a fully underground cable network or is adequately protected against atmospheric surges. However, live work is prohibited when performed in wet environments.




B6. Work without voltage

Basic prescriptions

• Section off the part of the system you are working on.
• Take measures against the inadvertent re-closure of disconnect devices.
• Make sure the system is off.
• Earth and short-circuit the disconnected parts in HV and MV and, where required, also in LV.
• Provide protection for any adjacent live parts.




Identifying underground low-voltage or medium-voltage cables, especially when there are other similar cables in the same excavation and route, requires particular attention. In these cases, after de-energizing and securing the cable at its ends, at points where its identification is certain, such as in the substation, you can proceed as follows, depending on the system:

- on low voltage lines, by checking for the absence of voltage using specific instruments and equipment (e.g. using insulation piercing terminals) or by cutting the point where you want to work on it;

- on MT lines, through cutting, which must be carried out with cable-cutting shears with insulation suitable for the operating voltage of the cable, built according to the relevant product standards (e.g., for voltages up to 30 kV, according to the CEI EN 50340 standard).

In any case, the cutting also serves as a check for the absence of voltage on the system.

Approval to begin work must be given to workers exclusively by the PL, who is responsible for ensuring safety during the execution of the work, after implementing the measures described above. Each person involved in the activity must be a PES or PAV (Professional Safety Officer) or must be under the supervision of a PES (Professional Safety Officer).

B7. Working under low voltage (categories 0 and I)

This procedure is only valid for category 0 and I systems (Voltage ≤ 1000 V AC and 1500 V DC).

Personnel working under voltage must be PES or PAV and have obtained the suitability for working under voltage on category 0 and i systems. This suitability must be certified and issued by the employer (DDL).

The Employer is responsible for certifying suitability for live work on Category 0 and I systems.

To obtain the qualification, the person must possess theoretical knowledge for working under voltage at level 2A and practical knowledge at level 2B.




B8. Low voltage working methods

A. Working with insulating rods

The operator must use only insulating rods to come into contact with the live part.

B. Work with insulating gloves

The operator comes into contact with the live part using insulating gloves.

Working under contact voltage




• The parts at different potentials (phases, neutral, masses) in the part of the system on which the work is being carried out must be separated by insulating screens (partitions, insulating tapes or bands, insulating mastic, etc.) to avoid the risk of accidental short circuits and consequent electric arc.
  
• The condition of the components on which work is carried out under voltage must be such as to exclude the risk of breakages and movement of the live metal parts and the risk of short circuits.
  
• Moving live parts, such as uninsulated cable ends, must not be left by the operator until they have been insulated or secured.




To carry out work under live contact, the operator must wear the following Personal Protective Equipment to protect against electrical risks:

- insulating gloves,
- protective visor,
- insulating helmet;
- suitable clothing that does not leave parts of the trunk and limbs uncovered.




B9. Bare-handed work

The operator must keep himself at the same potential as the active part on which he operates.




Working under tension with bare hands

• The work area must consist of a clearly identified area.
• It must not be possible for operators to touch, even outside the work area, parts with a different potential (for example the ground or masonry or concrete buildings, etc.).
• Operators must be placed on insulated or metal platforms equipped with metal guardrails, insulated from the ground. Metal platforms must be permanently connected to the live part before the operators touch it. Equipotential bonding of all metal parts connected to the platform must be ensured.
• No physical connection is permitted between the platform and other parts at different potentials other than those made with insulating rods or ropes. The platform's insulation from the ground must be checked periodically.

B10. Exclusions from live work

The following operations carried out on electrical systems or equipment under voltage even above 1000 V AC and 1500 V DC, carried out in compliance with the relevant technical standards, provided that equipment and procedures compliant with the technical standards are used and the personnel are adequately trained and instructed, do not constitute live work regulated by the CEI 11-15 standard:

- operation of sectioning, interrupting and regulating devices and of fixed earthing and short-circuiting devices, under normal operating conditions;
- operation of the above-mentioned devices using insulating rods, under normal operating conditions;• use of voltage detectors and comparators, constructed and used under the conditions specified by the manufacturer or by the product standards themselves;
- use of insulating distance detectors under the intended conditions of use;
- washing of insulators carried out by fixed automatic or remote-controlled systems; • use of mobile earthing and short-circuiting devices;
- jobs in which work is carried out on components that are part of machines or equipment powered by a voltage not exceeding 1000 V AC, even if they operate at a higher voltage.

The use of equipment and tools during operations relating to testing, fault finding, etc., which can technically only be performed in the absence of earthing and in the short circuiting of live parts that have been de-energized, does not constitute live work, provided that, following a risk analysis, test procedures (or methods) are adopted aimed at preventing the aforementioned live parts from being re-energized from any possible power source (see also section 5.3.2).



B 11. Operating modes

The choice of how to carry out the work is the responsibility of the PL, based on the characteristics of the system, the nature of the intervention, the personnel with the required qualifications made available, the PPE provided, etc.

When assessing whether to carry out live work, the presumed short-circuit current at the point where the work is being carried out and the response time of the upstream short-circuit protection device (fuses, current-limiting switches, etc.) must also be taken into account.

Personnel carrying out work under voltage must possess all the requirements set out in this technical standard.

Before performing live work, the RI and PL, each within their respective areas of expertise, must work collaboratively to prepare the work and implement the necessary safety measures. The work area, which is dangerous for live work because it contains the live parts to be worked on, must be clearly demarcated in the presence of certified electrical safety devices. Warning signs must also be posted prohibiting access to unauthorized persons. Only the PL and those authorized by him are permitted in the work area.




B12. Work organization




RI Tasks

1. Draw up the work plan.
2. Place and maintain the system in the condition envisaged by the work plan.
3. Identify the work area.




PL tasks to be performed before starting the execution of the works

1. Agree with RI on the methods of carrying out the work.
2. Verify that the work can be performed in compliance with the regulations and company procedures.
3. Check that there are no live parts accessible at a distance less than_v within the area in which the operation is taking place.
4. Check that any metal parts not protected against direct contact are not live.
5. Check that the collective equipment is efficient.
6. Verify that the person carrying out the work uses the required protective equipment and tools.
7. Communicate specific information about the work to be done to the workers.
8. Check for the RI notification for the start of the works.

Work near live parts

When working near live parts of any kind, safety systems such as screens, barriers, enclosures, insulating protectors, provision of safety distances, provision of supervision and/or surveillance must be adopted.

Work in proximity must be carried out by a PES or PAV. Ordinary persons (PEC) may carry out work in proximity provided that a PES manages the electrical risk through supervision or surveillance (the latter can also be carried out by a PAV).


C. Maintenance procedures




Maintenance work is of two types:

• work where there is a risk of shock, short circuits or electric arcs and therefore the appropriate working procedures described in the previous paragraphs must be applied;
• jobs where the design of the equipment allows for maintenance without electrical risk.




All maintenance procedures to be performed must be approved by the Electrical System Manager (URI or RI).

The personnel carrying out the work must be PES or PAV and suitable for working under voltage, when necessary.




C1. Temporary interruptions

In the event of temporary interruptions to maintenance work, the PL must take all necessary measures to prevent access to live parts and unauthorized operation of the electrical system. If necessary.

Inform RI of any interruptions.




C2. End of maintenance work

Upon completion of maintenance work, the Maintenance Supervisor must hand over the system to the RI. The status of the electrical system undergoing maintenance must be reported to the RI.

Further information for safe work

Example of levels of responsibility

General scheme

Example of role division in the organization of electrical work performed on system element 3, which involves interventions/maneuvers on other system elements located within the green areas delimited by dotted lines. To perform the electrical work on system element 3, the following interventions were required:

- partially the system elements 4 and 5 (the elements not subject to interventions/manoeuvres remain in “normal operating” configuration and therefore remain under the responsibility of URI);
- the system element 2 entirely.

Therefore, the areas with a green background have been subject to manoeuvres/interventions by RI (b) which assumes responsibility for ensuring their safety for the entire duration of the works.

Element 3 and the surrounding area with a yellow background, identified as the "work station", are handed over to the PL (c) who, by coordinating the workers (d), will assume responsibility for the safe execution of the work itself. The entire white area, which includes the entire element 1 and parts of elements 4 and 5, has not been affected by any interventions/maneuvers, therefore it maintains the status of "normal operation" and remains under the responsibility of URI (a) as it is not involved in the electrical work. As can be seen, URI's role is not affected in the organization of the electrical work.

In the case of particularly complex projects from an executive and/or organizational standpoint, the URL is responsible for preparing the project and sharing it with the PL who will lead it on site. For simpler projects, this role coincides with the person who holds the PL role.




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URI Classification): Owner

Classification RI), PL) and Workers): electricians

Small business or craftsman

URI classification: owner (e.g., baker who owns a bakery)

Classification RI), PL) and Workers): electricians

Large industrial company

URI Classification): Employer or executive staff or those responsible for overall electrical system responsibility

RI classification): person designated to act as manager of an electrical system during work activities

PL classification): head of a team in your own company or a third party company

Classification of workers: members of the work team