UL 60947-7-3-2017 pdf download

UL 60947-7-3-2017 pdf download.Low-Voltage Switchgear and Controlgear – Part7-3: Ancillary Equipment – Safety Requirements for Fuse Terminal Blocks.
8.4.3.1 General
a) If the manufacturer has declared a value tor the rated impulse voltage U, the impulse withstand voltage test shall be made in accordance with 8.3.3.4.1, item 2), of IEC 60947-1, except item 2) C) which does not apply.
b) According to the rated insulation voltage, the power-frequency withstand test shall be made in accordance with 8.3.3.4.1. Item 3), of IEC 60947-1.
The value of the test voltage shall be as stated in table 12A of lEG 60947-1 (see 8.3.3.4.1, item 3) b) I), of IEC 60947-1).
8.4.3.2 Test arrangement and application of the test voltage
8.4.3.2.1 General
Each test shall be carried Out on five adjacent fuse terminal blocks wired with conductors of the rated cross-section and installed on a metal support under the following conditions:
— the conductor ends shall be stripped to a length specified by the manufacturer;
— in case the manufacturer has stated the possibility of using different metal supports, the most unfavourable support shall be used.
8.4.3.2.2 Test A
Gauge no. 3 or no. 6, according to table Al, shall be properly inserted as in normal use depending on the size of the fuse terminal block, Indicators, it any, shall be removed or disconnected during this test.
Successively, the impulse withstand test voltage in accordance with the rated Impulse withstand voltage at the considered fuse-carrier and the power-frequency withstand test voltage corresponding to the
rated insulation voltage of the fuse-carrier shall be applied between the contact elements of each fuse terminal block.
8.4.3.2.3 Test B
Gauge no, 1 or no. 4, according to table Al, shall be property inserted as in normal use depending on the size of the fuse terminal block
Successively, the impulse withstand test voltage in accordance with the rated impulse withstand voltage at the terminal block base and the power-frequency withstand test voltage corresponding to the rated
insulation voltage of the terminal block base shall be applied between
— the live parts of adjacent fuse terminal blocks of the same type and size:
— the live parts of different polarity:
— the live parts connected together and the support.
8.4.3.3 Form and number of impulses
The 1.2(50 ps impulse voltage shall be applied three times with intervals of at least 1 S between the
individual pulses for each pofarity.
NOTE Th. output impedance of the puN. generator shoid not esc..d 500 IL For the description of the test equipment. see IEC 61180.1 and IEC 51180-2. During these lest. there should be no tlashoer or disruptive discharge. Corona etfects or s4milar phenomena that do not lead to a voltage breakdown Ire distegarded.
8.4.4 Contact resistance
8.4.4DV 02 Deletion:
Subclause 8.4.4 does not apply.
8.4.4.1 General requirements for measurement
The accuracy of the measuring apparatus shall be within ±3
The contact reststance shall be measured after the fuse terminal block has been equipped with gauge no. 2 or no. 5, according to table A. 1.
In the case of fuse terminal blocks with screw-type fuse-carriers, the carrier shall be installed as In normal use with a torque equal to two-thirds of the value specified in table 1.
Fuse terminal blocks with plug-on type o hinged-type fuse-carriers shall be installed as in normal use and tested in this condition,
8.4.4.2 Measuring cycle and measurement performance
8.4.4.2.1 General
The contact resistance is normally calculated from the voltage drop measured according to figure 1.
8.4.5 Temperature rise of clamping units
Five fuse terminal blocks shall be installed side by side on a support according to figure 1 as in normaluse,together with the required accessories and the minimum gauge no. 2 or no. 5 inserted according totable A.1.
Conductors and test currents shall be in accordance with 8.5.2.4.
The conductors shall be tightened with the torque as specified in table 4 of IEC 60947-1, in accordancewith the respective table C.1 of lIEC 60947-7-1 for screw-type clamping units with a diameter of threadsup to and including 2,8 mm, or with a higher torque as stated by the manufacturer.