In electrical installation work, the key parties connected to the delivery and the performance of work in addition to the customer and electrical contractor are the electrical designer, the wholesaler supplying the installation materials, the equipment and system suppliers (distribution board manufacturer, air conditioning machines, automation, etc.), any work stages implemented by subcontractors and, on larger sites, an authorised inspector or an inspecting body. In the repair of electrical equipment, the manufacturer’s instructions play a central role.
Prior to 1996, electrical design activities were regulated by qualification requirements in the manner of electrical contracting activities. Although formal qualification requirements no longer exist, the electrical installations done according to the electrical designs must naturally meet the electrical safety requirements.
Electrical contractors often purchase the installation materials and accessories through electrical wholesalers. Manufacturers and importers are obligated to ensure the safety of the products they supply. Should the electrical contractor have reason to suspect that a material or accessory is not adequate, he/she should ask to see a declaration of conformity in accordance with the Low Voltage Directive, or other corresponding report on the product’s safety and conformity with the regulations.
Equipment suppliers or systems suppliers may include kitchen appliance suppliers, distribution board manufacturers or suppliers of larger systems such as air conditioning, automation, etc. Depending on the case, their delivery may be entirely the electrical contractor’s responsibility, or the customer purchases them from elsewhere and uses the contractor’s services for their installation only. However, the electrical contractor should ensure that the delivered equipment and systems are safe and appropriate.
If the electrical contractor subcontracts part of the work, he/she should carefully consider all interfaces between the tasks and agree in detail on who is responsible for what. Special attention should also be paid to ensuring electrical safety during work, if persons from several different companies are working on the same site. Subcontractors performing electrical work must have their own authority to perform electrical contracting work.
Electrical Safety during Work
When constructing or repairing electrical equipment, it is essential to observe safe work methods. One must also ensure that outsiders cannot enter the dangerous area and that power cannot be switched on to inadequately protected parts through a simple operation, such as turning an unlocked switch or circuit breaker.
The occupational safety requirements are set forth in the Occupational Safety and Health Act (738/2002) and other decrees issued under it. The special requirements for the prevention of electrical hazards are issued in the Decision of the Ministry of Trade and Industry 516/1996, and more detailed requirements can be found in standard SFS 6002, “Safety at Electrical Work”.
Structural Safety Requirements of Electrical Equipment
The essential safety requirements for electrical equipment (electrical installations) are issued in the Decision of the Ministry of Trade and Industry on Safety of Electrical Installations (1193/1999). The requirements are considered to have been met when the installation is performed following the standards listed in Tukes Instruction Letter 12/2015 (S10-2015).
Installations not exceeding 1,000 V are primarily performed in accordance with the SFS 6000 series of standards (Low-voltage Electrical Installations) and installations exceeding 1,000 V in accordance with the standard SFS 6001 (High-voltage Electrical Installations). The Tukes Instruction Letter S10 also lists special requirements for certain equipment and spaces, such as standards on overhead lines and electrical installations in potentially explosive atmospheres.
Commissioning an Electrical Installation
Before an electrical installation or its part is commissioned, the electrical contractor must perform a commissioning inspection to ensure electrical safety. It includes a visual inspection and various measurements and tests. The commissioning inspection report is handed over the customer of the electrical work.
The electrical contractor must also have a certification inspection done on electrical installations covered by the electrical installation categories defined by the statutes. A certification inspection is carried out for residential buildings larger than a semi-detached house, other electrical installations with a main fuse of over 35A, and some special spaces regardless of fuse size. For change work, the most common limit is a work area with an over 35A overcurrent protection. For more details, see the Decision of the Ministry of Trade and Industry on Commissioning and Use of Electrical Installations (517/1996).
Certification inspections are performed by authorised inspection bodies and authorised inspectors who have been accredited by Tukes.