Electrical laboratory and commissioning works
Evropeyskaya Elektrotekhnica provides the following services:
- Putting facilities into operation and performing commissioning works;
- Performing works specified in the regulations of the electric and technical laboratory, providing required documents and technical reports.
Our electric and technical laboratory in Moscow has the certificate of incorporation and competency certificate for the following types of tests and measurements:
- insulation resistance,
- phase to ground loop,
- metallic bonding,
- grounding contour,
- machine examination,
- testing of GFCI.
Electrical measurements and tests of electric equipment are held at electric plants with capacity up to 1,000 V.
The electric and technical laboratory takes all the electrical measurements with modern devices ensuring maximum accuracy of equipment diagnostics and reliable results.
Electrical measurements are carried out in order to check compliance of the electrical installation parameters with the project, the relevant regulatory documents (Electrical Code and Regulations for Operation of Consumer Electrical Installations of electrical grids and electrical equipment), as well as for timely detection of defects that may lead to emergency and fire hazardous situations, and interruption of production or office work. The results of tests and measurements are recorded in protocols which are part of the technical report.
Tests conducted by the electric and technical laboratory
Electrical start-up testing is carried out after completion of electrical installation works. The technical report, prepared in accordance with the results of tests, is included in documentation necessary for commissioning of the electrical equipment.
Periodic (maintenance) tests are conducted in accordance with the requirements of regulatory and technical documentation and the inspecting bodies. The frequency of tests and measurements is determined by the characteristics of the installation, the conditions of its operation, as well as the current rules and regulations.
Preventive (inspection) tests are conducted to detect electric grids and electric equipment which is faulty or inconsistent with the regulations and rules of electric installations (Electrical Code, Regulations for Operation of Consumer Electrical Installations, Safety Regulations) in order to avoid accidents, emergencies, and ignition of electrical wiring.
Technical report contents
- The front page contains information about the electrical and technical laboratory, the name of the organization, the full customer address and date of the conducted measurements;
- A copy of the Certificate of Incorporation;
- A copy of the Competency Certificate;
- An explanatory note describing the method and progress of conducting the measurements.
Protocols of PJSC Evropeyskaya Elektrotekhnica's electric and technical laboratory
- Protocol No. 1 — Visual inspection: testing compliance of the electric equipment with the regulatory and technical documentation.
- Protocol No. 2 — Protocol verifying electric continuity between grounding devices and its components.
- Protocol No. 3 — Insulation resistance measuring of wires and cables with voltage up to 1,000 V.
- Protocol No. 4 — Testing compliance of the phase to ground circuit parameters with the characteristics of protectors and continuity of protective conductors.
- Protocol No. 5 — Verification of automatic supply disconnection by direct measurement of a single phase current.
- Protocol No. 6 — Protocol of ground fault circuit interrupters (GFCI) examination and testing.
- Protocol No. 7 — Resistance measuring of grounding devices.
Types of measurements
Insulation resistance of conductors and cable line conductors are measured between each other and in relation to grounded conductors. Insulation resistance must be at least 0.5 Mohm.
Grounding device resistance (contour of grounding) is measured in electric equipment with voltage of solid grounded neutral up to 1,000 V in accordance with cl. 3, subcl. 3.1 of the Electrical Code and Regulations for Operation of Consumer Electrical Installations regulatory documents. At any time of the year, grounding devices resistance must not exceed 2, 4 and 8 Ohm with the cable voltage of 660, 380 and 220 V of the three-phase current source and 380, 220 and 127 V of the one-phase current source.
Such measurements are carried out in order to detect integrity and continuity of protective conductors from a measured object to a grounding device or from a grounding grid to an equipotential bonding conductor, as well as to detect the resistance of a measured section of the protective circuit. Thus, the voltage and its absence of the grounding parts of the tested equipment is being diagnosed in the standard operating mode.
Resistance measurements are conducted between an open conductive part and the nearest main conductor point of the potential control system. Protective conductors are primarily metal electrical pipes and metal cable jackets.
The resistance of grounding conductors contact must not exceed 0.05 Ohm. The measured resistance of protective conductors must not exceed 1.2 times the calculated value.
The phase to ground loop is measured to inspect operating characteristics of protection devices in the short circuit. To test reliability and quick disconnection of a faulty part of a grid, the short-circuit current to the housing Isc is measured (short-circuit current Isc is the ratio of the nominal grid voltage to the impedance of the phase to ground loop). Then, it is compared with the calculated protection operating current of the tested grid section. The reliability of disconnection is considered to be ensured when the current of the emergency mode, possible in the given section of the grid, exceeds the current of protection operation with sufficient multiplicity. Isc is compared with the standards of the Regulations for Operation of Consumer Electrical Installations.
Along with the overcurrent protection devices, protection tripping devices that respond to differential current are related to additional types of protection from damage under indirect contact due to automatic power-off. GFCI is considered necessary for use in electric service panels of buildings under construction or reconstruction, relocatable buildings made of metal or with metal frames, cottages, etc. in accordance with the Electrical Code and a range of standards and regulations (GOST R 50669-94, the set of standards GOST R 50571, NPB 243-97, MGSN 3.01-96, etc.).
During tests the following steps are carried out:
- Determination of a GFCI operating level.
- Measurement of leakage current in the GFCI's protection zone.
- To test the overall GFCI's operational capacity, a testing circuit is provided, by means of which a breaking differential current is artificially created. The response of GFCI means that the device operates properly.
Circuit interrupters are used for conducting, switching and automatic disconnection of electric circuits under abnormal conditions (for example, overload currents, short circuit, unacceptable voltage reduction), and also for rare switching of circuits manually.
Tests of the circuit interrupters' releases are conducted in order to check the compliance of the limits of their operation with the data declared by the manufacturer, and the requirements of GOST R 50345-99, GOST R 50030.2-99. Operational parameters of circuit interrupters shall comply with the manufacturer's data and provide electric shock protection in short circuits (in case of failure of other protective measures) and grid overload and fire protection due to technological overloads or insulation damage. During protection verification of grids from overload, the time of response for circuit interrupters shall be defined according to the technical passport and depend on the ambient temperature and rated current ratio.
There are several types of circuit interrupters: circuit interrupters with inverse time lag (thermal), with independent time lag, and instant ones (electromagnetic and electronic). Thermal releases are activated with a delay, depending on the current: if the current increases, the delay decreases. Electromagnetic circuit releases response with no delays. According to GOST R 50345-99, circuit interrupters for domestic use are classified according to the range of current in the instantly broken circuit and are included into the categories B, C, and D.