A Colombian technical standard, “NTC 2244 Connectors for use between bare aluminum-to-aluminum or aluminum-to-copper overhead conductors”, describes the requirements for connectors used to make electrical connections between bare aluminum-to-aluminum or aluminum-to-copper conductors used in overhead distribution and transmission lines by energy companies.
This standard specifies the current carrying and mechanical performance requirements for connectors for continuous use on conductors under normal operating conditions. Other operating conditions than those normal should be discussed with the connector manufacturer.
The intent of this standard is to provide the user with reasonable assurance that connectors meeting the requirements specified herein will perform satisfactorily when properly selected for the intended application and installed in accordance with the manufacturer's recommendations.
Although there are nine possible combinations of electrical and mechanical classes listed in this standard, it is expected that they will meet the usual requirements for a given range of conductor sizes. However, this does not exclude other combinations.
In terms of test conditions, connectors must be installed in accordance with those specified in this standard and subjected to current flow and mechanical operation tests. The sampling plan for receiving the product is agreed upon between the purchaser and the manufacturer.
Cyclic current tests shall be performed in accordance with this standard and shall have the following duration depending on the current class of the connector:
Within the scope of mechanical tests, the tensile strength tests of the connection, the reusability of the connector and its effect on the resistance of the conductor should be carried out as specified in this standard for the mechanical resistance class according to the following list:
Connectors shall meet the appropriate performance requirements specified in this standard when installed and tested in accordance with the methods specified in this standard.
The electrical resistance of a connection tested in accordance with this standard shall be stable between cycle 25 and the completion of the number of cycles required for the type of connector being tested. Stability is achieved when any electrical resistance measurement, including measurement errors, does not differ by more than plus/minus 5 percent from the average of all measurements over this range.
The temperature of the connector tested in accordance with this standard shall not be higher than the temperature of the control conductor. The difference between the temperature of the control conductor and the temperature of the connector shall be stable between the 25th cycle and the last cycle required for the class of conductor under test. Stability is achieved if any temperature difference between the control conductor and the connector, including measurement errors, does not exceed 10 per cent of the average of all differences over this range.
In terms of the tensile strength of the conductor, the tensile strength of connectors tested in accordance with this standard shall be equal to or greater than the values specified in this standard.
In terms of the nominal mechanical resistance of the conductor, the nominal mechanical strength of the conductor as used in this standard shall be calculated in accordance with the requirements of the applicable ASTM standards listed in the normative references or, for standard conductors, in accordance with the manufacturer's instructions.
Tensile strength classes are as follows:
After completion of all tests, reusable type connectors shall be capable of being reconnected and in service with all conductor combinations for which they are intended. Screw connectors meet this requirement if their resistance to bending specified in this standard is equal to or greater than 120 percent of the tightening torque specified in the table provided.
Tap connectors meet the mechanical requirements if the resistance of the conductor is 90 percent or more of nominal after conductor damage testing specified in this standard.
Among the numerous testing, measurement, analysis and evaluation studies that our organization has provided for businesses in various sectors, our organization also provides testing services defined in the standard “NTC 2244 Connectors for use between bare overhead conductors from aluminum to aluminum or from aluminum to copper” with its trained and expert staff and advanced technological equipment.
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