Work on Electrical Installations and in premises presenting a fire or explosion hazard
Definitions and concepts:
20. Technical instructions
20.3. Carrying out of live work on low voltage using the “in Contact” method
Roles
Person responsible for the LVI
To authorise the carrying out of LVW on said installation, after a study has been carried out by him or by personnel in his charge.
Foreman
- To previously appraise the installation on which work is to be carried out.
- To determine, at all times, the implementation of Procedures.
- To have in-depth knowledge of the work to be done.
- To instruct the personnel in his charge regarding the task and the Procedure or Procedures to apply.
- To check the state of the tools and materials to use and to take charge of replacing any defective tool or material.
- To decide on the appropriate Specific Work Procedure, depending on the job and the installation, and to ensure that this is respected at all times.
- To decide, when applicable, when to suspend or interrupt LVW.
- To assume responsibility for the quality of the work.
- To communicate to the Person Responsible for the LVI any incidents that might arise in the course of LVW with the aim of continuously improving the application of the Procedures.
LVW Electrician
- To check his personal protection equipment and tools, which he is to use at all times during the job.
- To respect the order of the operations established in the Specific Work Procedure, helping the person doing the work or carrying out the tasks that have been previously established.
Number of persons
To carry out any kind of live work on LV via the “in Contact” method, at least two electricians with valid qualifications are needed. One of these is to assume the role of Foreman.
Prior study
A prior feasibility study is to be conducted in all jobs which, depending on the installation and on the characteristics of the task, will reveal the convenience of carrying out live work or not.
Checks
Material, personal and collective protections and insulating tools are to be checked, replacing those that present signs of wear in their insulation.
If any material that is essential for carrying out LVW should be missing or be deteriorated, the commencement of said work is to be postponed until such material has been replaced, or the work is to be done with the power disconnected, i.e. dead.
The use of non-approved tools is likewise forbidden, as is altering the original characteristics of the material.
Testing of gloves
Leakage testing of insulating gloves is mandatory every time they are used. Furthermore, all material must undergo periodic checks in the terms stipulated by the Firm.
Work clothes
Work clothes must not leave any part of the body uncovered. Workers are to take off all metal objects in Contact with their skin (watches, bracelets, rings, earrings, etc.).
Insulation of conducting elements
Earths and live parts are to be insulated as work advances. (ADVANCE PROTECTING AND RETREAT EXPOSING) Insulating gloves protect the point of entry of current into the body. Via appropriate insulation of the earths and live parts that come together in the work area, the electrician is insulated from any exit point, in addition to preventing unforeseen Contact.
Exposed points
Only one live point is to be left exposed, which will be the one being worked on. When, just before connecting, two points are exposed, the following conditions must be fulfilled:
- They must be at the same potential, with another path in the same circuit closed and locked-out: Bridge or by-pass.
- One is to be at the potential and the other on the circuit, effectively open. This circumstance is repeated immediately after disconnection.
Neutral
The neutral conductor is always be the first to be connected and the last to be disconnected. It is always to be considered as an active conductor.
Development of the Job
The appropriate Specific Work Procedures are to be applied in each case with the utmost attention and rigour. When faced with any doubt, work is not to be commenced or is to be interrupted.
Demarcation and Signposting
Suitably signposting and demarcating of the Work Area is mandatory.
Communication
To carry out LVW, it is essential to inform the corresponding Operations Centre of the commencement and completion of such work.
