PERMANENTLY CONNECTED EQUIPMENT and equipment with ordinary NON-DETACHABLE POWER SUPPLY CORDS shall be provided with terminals in which connection is made by means of screws, nuts or equally effective devices (see also 2.6.4).
Compliance is checked by inspection.
3.3.2 Connection of non-detachable power supply cords
For equipment with special NON-DETACHABLE POWER SUPPLY CORDS, the connection of the individual conductors to the internal wiring of the equipment shall be accomplished by any means that will provide a reliable electrical and mechanical connection without exceeding the permitted temperature limits while the equipment is operated under NORMAL LOAD
(see also 3.1.9).
Compliance is checked by inspection and by measuring the temperature of the connection which shall not exceed the values of 4.5.3, Table 4B.
3.3.3 Screw terminals
Screws and nuts that clamp external MAINS SUPPLY conductors shall have a thread conforming to ISO 261 or ISO 262, or a thread comparable in pitch and mechanical strength (for example, unified threads). The screws and nuts shall not serve to fix any other component, except that they are permitted also to clamp internal conductors provided that the internal conductors are so arranged that they are unlikely to be displaced when fitting the supply conductors. For protective earthing terminals and protective bonding terminals, see also 2.6.4.2.
The terminals of a component (for example, a switch) built into the equipment are permitted for use as terminals for external MAINS SUPPLY conductors, provided that they comply with the requirements of 3.3.
Compliance is checked by inspection.
3.3.4 Conductor sizes to be connected
Terminals shall allow the connection of conductors having nominal cross-sectional areas as shown in Table 3D.
Where heavier gauge conductors are used, the terminals shall be sized accordingly.
Compliance is checked by inspection, by measurement and by fitting cords of the smallest and largest cross-sectional areas of the appropriate range shown in Table 3D.
Table 3D – Range of conductor sizes to be accepted by terminals
Nominal cross-sectional area mm2
RATED CURRENTof equipment
A Flexible cords Other cables
Up to and including 3 Over 3 up to and including 6 Over 6 up to and including 10
Over 10 up to and including 16
Text deleted
Over 16 up to and including 25 Over 25 up to and including 32 Over 32 up to and including 40 Over 40 up to and including 63
0,5 to 0,75 0,75 to 1 1 to 1,5 1,5 to 2,5
2,5 to 4
4 to 6
6 to 10 10 to 16
1 to 2,5 1 to 2,5 1 to 2,5
1,5 to 4
2,5 to 6 4 to 10 6 to 16 10 to 25
3.3.5 Wiring terminal sizes
Pillar, stud or screw type terminals shall comply with the minimum sizes in Table 3E.
Compliance is checked by inspection and measurement.
EN 60950-1:2006+A12:2011 (E)
– 133 –
Table 3E – Sizes of terminals for mains supply conductors and protective earthing conductorsa
3.3.6 Wiring terminal design
Wiring terminals shall be so designed that they clamp the conductor between metal surfaces with sufficient contact pressure and without damage to the conductor.
Terminals shall be so designed or located that the conductor cannot slip out when the clamping screws or nuts are tightened.
Terminals shall be provided with appropriate fixing hardware for the conductors (for example, nuts and washers).
Terminals shall be so fixed that, when the means of clamping the conductor is tightened or loosened, all of the following apply:
− the terminal itself does not work loose;
− internal wiring is not subjected to stress; and
− CLEARANCES and CREEPAGE DISTANCES are not reduced below the values specified in 2.10 (or Annex G).
Compliance is checked by inspection and measurement.
3.3.7 Grouping of wiring terminals
For ordinary NON-DETACHABLE POWER SUPPLY CORDS and for PERMANENTLY CONNECTED EQUIPMENT, all associated AC MAINS SUPPLY terminals shall be located in proximity to each other and to the main protective earthing terminal, if any.
For ordinary NON-DETACHABLE POWER SUPPLY CORDS and for PERMANENTLY CONNECTED EQUIPMENT, all associated DC MAINS SUPPLY terminals shall be located in proximity to each other. They need not be located in proximity to the main protective earthing terminal, if any, provided the installation instructions detail the proper earthing of the system.
Compliance is checked by inspection.
RATED CURRENT up to and including A
Conductor size mm2
Minimum nominal thread diameter
mm
Area of cross section mm2
Pillar type or
stud type Screw type b Pillar type or
stud type Screw type b 10
16 25 32 40 63 80
1 1,5 2,5 4 6 10 c 16 c
3,0 3,5 4,0 4,0 5,0 6,0 7,9
3,5 4,0 5,0 5,0 5,0 6,0 7,9
7 9,6 12,6 12,6 19,6 28 49
9,6 12,6 19,6 19,6 19,6 28 49
a This table is also used for the sizes of terminals for PROTECTIVE BONDING CONDUCTORS if specified in 2.6.4.2.
b "Screw type" refers to a terminal that clamps the conductor under the head of a screw, with or without a washer.
c As an alternative to the requirements of this table, the protective earthing conductor may be attached to special connectors, or suitable clamping means (for example, an upturned spade or closed loop pressure type; clamping unit type; saddle clamping unit type; mantle clamping unit type; etc.) that is secured by a screw and nut mechanism to the metal chassis of the equipment. The sum of the cross-sectional areas of the screw and the nut shall not be less than three times the cross-sectional area of the conductor size in Table 2D or Table 3B as applicable. The terminals shall comply with IEC 60998-1 and IEC 60999-1 or IEC 60999-2.
#
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3.3.8 Stranded wire
The end of a stranded conductor shall not be consolidated by soft soldering at places where the conductor is subject to contact pressure unless the method of clamping is designed so as to reduce the likelihood of a bad contact due to cold flow of the solder.
Spring terminals that compensate for the cold flow are deemed to satisfy this requirement.
Preventing the clamping screws from rotating is not considered to be adequate.
Terminals shall be located, guarded or insulated so that, should a strand of a flexible conductor escape when the conductor is fitted, there is no likelihood of accidental contact between such a strand and
− accessible conductive parts, or
− unearthed conductive parts separated from accessible conductive parts by
SUPPLEMENTARY INSULATION only.
Compliance is checked by inspection and, unless a special cord is prepared in such a way as to prevent the escape of strands, by the following test.
A piece of insulation approximately 8 mm long is removed from the end of a flexible conductor having the appropriate nominal cross-sectional area. One wire of the stranded conductor is left free and the other wires are fully inserted into, and clamped in the terminal.
Without tearing the insulation back, the free wire is bent in every possible direction, but without making sharp bends around the guard.
If the conductor is at HAZARDOUS VOLTAGE, the free wire shall not touch any conductive part that is accessible or is connected to an accessible conductive part or, in the case of DOUBLE INSULATED equipment, any conductive part that is separated from accessible conductive parts by SUPPLEMENTARY INSULATION only.
If the conductor is connected to an earthing terminal, the free wire shall not touch any part at
HAZARDOUS VOLTAGE.