UL 60947-7-1-2011 pdf download

UL 60947-7-1-2011 pdf download.Low-voltage switchgear and controlgear – Part 7-1:Ancillary equipment— Terminal blocks for copper conductors.
8.3.3.2 Testing for damage to and accidental loosening of conductors of a terminal block (flexion test)
Subclauses 8.2.4.1 and 8.2.4.3 of IEC 60947-1 apply with the following modification.
Each test shall be carried out on two clamping units of one terminal block.
For screw-type clamping units with a diameter of threads up to and including 2,8 mm, the tightening torque shall be in accordance with table C.1 or the torque specified by the manufacturer.
The tests shall be made with the type (rigid and/or flexible) and the number of conductors stated by the manufacturer as follows:
— with the different types of conductor of the specified smallest cross-section (only one conductor connected);
— with the different types of conductor of the specified rated cross-section (only one conductor connected); and, if applicable,
— with the type(s) of conductor of the largest connectable cross-section, if larger than the rated cross-section (only one conductor connected);
— with the different types and maximum number of conductors of the smallest cross-section
simultaneously connectable;
— with the different types and maximum number of conductors of the largest cross-section simultaneously connectable;
— with the different types and maximum number of conductors of the smallest and largest cross-section simultaneously connectable.
8.3.3.3 Pull-out test
Subclause 8.2.4.4 of IEC 60947-1 applies with the following modification.
The pulling force is 15 N for a conductor having a cross-section of 0,34 mm2 (AWG 22) and 20 N for a conductor having a cross-section of 0,5 mm2 (AWG 20).
8.3.3.3 DV D2 Modification by replacing with the following:
Subclause 8.2.4.4 of IEC 60947-1, applies without the modification in pulling force.
8.4.2.2 Clearances
The measured values of clearances shall be higher than the values given in table 13 of IEC 60947-1 for case B — homogeneous field (see 7.2.3.3 of IEC 60947-1) depending on the value of the rated impulse withstand voltage Ujmp and the pollution degree stated by the manufacturer.
The impulse withstand voltage test shall be carried out in accordance with 8.4.3 a) unless the measured clearances are equal to or larger than the values given in table 13 of IEC 60947-1 for case A — inhomogeneous field (see 8.3.3.4.1, item 2), of IEC 60947-1.
8.4.2.3 Creepage distances
The measured creepage distances shall be not less than the values given in table 15 of IEC 60947-1 in connection with 7.2.3.4 a) and b) of IEC 60947-1 depending on the rated insulation voltage, the material group and the pollution degree as specified by the manufacturer.
8.4.2.3DV.1 D2 Modification for the U.S. by replacing 8.4.2.3 with 8.4.2.3DV.1.1 —
8.4 .2.3D V.1.6:
8.4.2.3DV.1.1 Spacings shall be measured through cracks or between sections of a sectional type terminal block. In applying Table 7.1.3DV.1, it shall be assumed that:
a) Adjacent poles are at opposite polarity; and
b) Any mounting surface is at ground potential.
8.4.2.3DV.1.2 Spacings are measured at all live parts of a terminal block, including factory terminations, i.e. printed circuit board solder pins. When soldered or wired in the actual end use application, these spacings shall be additionally evaluated in the end product.
8.4.2.3DV.1.3 A live screw head or nut on the underside of an insulating base shall be reliably prevented from loosening and shall be adequately insulated or spaced from the mounting surface. This may be accomplished by:
a) Countersinking such parts not less than 3,2 mm in the clear and then covering them with a waterproof, insulating sealing compound that does not melt at a temperature of 15°C higher than the normal operating temperature in the device, and not less than 100°C in any case, or
b) Reliably securing such parts and insulating them from the mounting surface by means of a barrier or the equivalent, or by means of through-air or oversurface spacings as specified in Table 7.1.3DV.1.
8.4.2.3DV.1.4 An insulating barrier or liner used as the sole separation between an uninsulated live part and a noncurrent-carrying metal part (including grounded metal part) or between uninsulated live parts of opposite polarity shall be of material that is acceptable for the mounting of an uninsulated live part and not less than 0,71 mm thick.