A current of 10 mA (1 ampere to 1000 milliamps) is sufficient for the person affected to feel severe pain. At an intensity of more than 75 mA, paralysis can have a serious effect on the body. Intensity of 1-4 A is the death sentence. At 5 A, there is a charring of tissues. From this conclusion that electricity must not be underestimated, especially on the construction site, where there are conditions very conducive to paralysis. There are places that are damp and wet, perfectly conductive of electricity. It is full of wires and electrical appliances. The work is tiring and stressful, so the workers have problems with self-control and can accidentally touch or hook up with some electrically conductive object.

The construction manager must instruct the construction manager about the risks associated with electricity and the safety of workers. Its task is also to wake up, assess and eliminate possible risks, and when dangerous situations occur – intervention. For the operation and repair of high-voltage equipment should be designated persons with appropriate privileges (qualification certificates „E” – operation with voltage input). The same applies to personnel involved in the installation, maintenance and repair of the electricity network on the construction site.

Networked devices are the biggest threat. Battery devices are the safest. Do not use electrical tools and machines if they are not fully functional, especially if they have damaged cable insulation. Do not move such devices unless they have been previously disconnected from the network. It is also necessary to ensure that they are not accidentally connected. It is forbidden to connect them to an inoperable electrical system. It is also forbidden to repair damaged tools and equipment yourself, and especially to use makeshift methods, for example, to trap holes in the insulation or exposed wires with insulating tape.

Electrical circuits to which construction equipment and other electrical equipment are connected on the construction site must be equipped with residual current fuses (circuit breakers) with a sensitivity of 30 mA, which, in the event of a short circuit, cut off the power supply in about 0,2 seconds.

In construction, 750 V-type OPd-reinforced cables should be used, with an appropriate number of wires for the supply of 1- and 3-phase portable receivers.

Basic safety rules

• The basic principle is formulated in standard PN – EN 61140:2005 „Protection against electric shock – common aspects of installations and equipment”. It is worth quoting here: „Hazardous active parts should not be available and conductive parts available should not be dangerous.”
• Workers should be trained to operate electrical equipment as well as to provide first aid to infested persons.
• The installation of the distribution of electricity on a construction site should be designed by an authorised professional and carried out by an electrician with the appropriate privileges.
• Electricity to workplaces should be distributed through so-called mobile or mobile switchgear, necessarily closed and protected against unauthorized access. The switchgear shall be arranged in such a way that the construction equipment connected to them does not have to be more than 50 m away from them.
• Installation equipment and fittings with a degree of protection of at least IP44 and switchgear with a degree of protection of at least IP43 shall be used.
• Electrical installations and equipment shall be protected by a selective residual current protective switch, rated differential current of not more than 500 mA, in plug socket circuits with a rated current exceeding 32 A and 30 mA in plug socket circuits with a rated current not exceeding 32 A.
• Extension cords used on constructions should be equipped with thermal protection or overcurrent protection. They can not be ordinary „homemade” extension cords.
• On the construction site should be used copper electrical wires type H07 RN-F.
• Electrical wires must be distributeed around the construction site so that they are not exposed to accidental damage. They can be placed in additional covers for this purpose. They should not lie on wet substrates or even sink in puddles.
• Plug sockets and plugs used in very low voltage circuits must not fit plugs and plug sockets used in other circuits.
• The permissible tactile voltage should be long-term limited to 25 V AC or 60 V DC.
• In construction conditions, equipment of protection class II should be used.
• All equipment and the electrical network on site must be maintained in good condition and regularly in-service and maintained.
• If any device or network faults are observed, fix them immediately.

Source: https://www.grupapsb.com.pl/porady/porada/ostroznie-z-pradem-ochrona-przeciwporazeniowa-na-budowie.html