9 Electric shock hazard under normal operating conditions
9.1 Testing on the outside
9.1.1 General
9.1.1.1 Requirements
ACCESSIBLE parts shall not be HAZARDOUS LIVE.
For interconnection with apparatus under the scope of other standards, circuits should comply with 9.1.1 and, depending upon the construction, with 8.5 or 8.6.
In addition, when not connected to another apparatus, inaccessible contacts of TERMINALS shall not be HAZARDOUS LIVE, with the following exceptions:
For PROFESSIONAL EQUIPMENT,audio output TERMINALS are permitted to be ACCESSIBLE to SKILLED PERSONS if the audio output voltage, when the apparatus is producing its NON-CLIPPED OUTPUT POWER, is not greater than 120Vr.m.s.
The requirements to determine whether a HAZARDOUS LIVE part is ACCESSIBLE apply only to HAZARDOUS LIVE voltages not exceeding 1000 Va.c. or 1500Vd.c. For higher voltages, there shall be a CLEARANCEbetween the part at HAZARDOUS LIVE voltage and the test finger or the test pin as specified in 13.3.1 for BASIC INSULATION(see Figure 3).
– contacts of signal output TERMINALS, if they have to be HAZARDOUS LIVE for functional reasons, provided the contacts are separated from the supply source as required according to Clause 8 for ACCESSIBLE conductive parts. Inaccessible input TERMINALS, for example those of loudspeakers, are permitted to be HAZARDOUS LIVE when connected to such output
TERMINALS.
NOTE For the marking of such output TERMINALS, see 5.3b).
– TERMINALS complying with 15.1.1provided for connecting the apparatus to the MAINS, socket-outlets and contacts of connecting blocks for providing power to other apparatus.
Compliance is checked by inspection and by measurements according to 9.1.1.2 and tests according to 9.1.1.3.
9.1.1.2 Determination of HAZARDOUS LIVE parts
In order to verify that a part or a contact of a TERMINAL is HAZARDOUS LIVE, the following measurements are carried out between any two parts or contacts, then between any part or contact and either pole of the supply source used during the test.
NOTE 1 For discharges between the poles of the MAINS plug, see 9.1.6.
a)The part or contact of a TERMINAL is HAZARDOUS LIVE if the open-circuit voltage exceeds
-35 V (peak) a.c. or 60V d.c.; or
-71 Vr.m.s. for audio signals of other than PROFESSIONAL APPARATUS; Or
-120Vr.m.s. for audio signals of PROFESSIONAL APPARATUS.
b) The part or contact of a TERMINAL is HAZARDOUS LIVE if the TOUCH-CURRENT, expressed as the corresponding voltages U₁ and U2, and measured in accordance with IEC 60990 with the measuring network described in Annex D of this standard, exceeds the following values:
– for a.c.: U₁ = 35 V (peak) and U2 = 0,35V(peak);
– for d.c.: U₁ = 1,0 V.
NOTE 2 The limit values of U₂ = 0,35 V (peak) for a.c. and U,= 1,0 V for d.c. correspond to the values 0,7 mA (peak) a.c. and 2,0 mA d.c.
The limit value U,= 35 V (peak) for a.c. corresponds to the value 70 mA (peak) a.c. for frequencies greater than 100 kHz.
NOTE 3 For apparatus intended to be used in tropical climates, the voltage limits given in a) and b) above are typically halved.
For CLASS I constructions, the r.m.s. TOUCH-CURRENT to earth shall not be more than 3,5 mA. The measurement shall be carried out with the measurement network described in Annex D of this standard and with the protective earthing connection disconnected.
Discharges shall be measured to the TERMINAL provided for connecting the apparatus to the supply source, immediately after the interruption of the supply. The part or contact of a TERMINAL iS HAZARDOUS LIVE if:
c) the charge exceeds 45 μC for stored charges at voltages between 60 V d.c. and 15 kVd.c.,or
d) the energy of discharge exceeds 350 mJ for stored charges at voltages exceeding 15 kVd.c.
9.1.1.3 Determination of ACCESSIBLE parts
In order to determine whether a HAZARDOUS LIVE part is ACCESSIBLE,the jointed test finger according to test probe B of IEC 61032:1997, is pushed against the enclosure or inserted through any openings of the enclosure, including openings in the bottom,without appreciable force.
Through openings, the test finger is applied to any depth that the finger will permit and is rotated or angled before, during and after insertion to any position. If the opening does not allow the entry of the finger, the force on the finger in the straight position is increased to 20N± 2 N and the test repeated with the finger in angled position.
The test is repeated using small finger probes according to test probes 18 and 19 of IEC 61032:1997. This does not apply if the intended conditions of use prevent the apparatus from being accessed by children.
Conductive parts, covered only by lacquer, solvent-based enamel, ordinary paper, untreated textile, oxide films or beads are considered to be bare.
Moving parts of loudspeaker systems, such as dust caps or cones of drivers or passive radiators, are not regarded as preventing accessibility.
NOTE 1 See also 13.3.1.
For CLASS II constructions, the test probe 13 of IEC 61032:1997 shall not touch HAZARDOUS LIVE parts when applied with a force of 3 N ±0,3 N in every possible position.
The test probe is not applied to socket-outlets, connectors providing MAINS power, fuse holders and the like.
NOTE 2 For indication of electrical contact, a voltage of not less than 40 V and not more than 50 V in series with a suitable lamp can be used.
9.1.2 Shafts of operating knobs, handles, levers and the like
Shafts of operating knobs, handles, levers and the like shall not beHAZARDOUS LIVE.
Compliance is checked by inspection, and in case of doubt, by measurement according to 9.1.1.2.
9.1.3 Openings of the enclosure
The apparatus shall be so designed that suspended foreign bodies cannot become HAZARDOUS LIVE, when introduced through ventilation or other holes.
Compliance is checked by applying to the holes a metal test pin having a diameter of 4 mm and a length of 100 mm. The test pin is suspended freely from one end; the penetration is limited to the length of the test pin.
The test pin shall not become HAZARDOUS LIVE.
9.1.4 TERMINALS
The use of a single-pole plug or a bare wire to make connection with a contact of a TERMINAL for earth or antenna or for audio, video or associated signals, shall not involve the risk of an electric shock.
The test is not applied to TERMINALS marked with the symbol of 5.3b).
NOTE See also 15.1.2.
Compliance is checked by the following tests:
Within 25 mm measured from each contact of the TERMINAL, a test pin according to IEC 61032:1997, test probe D, however limited in length to20 mm ± 0,2 mm, is applied in every possible position, in case of doubt with a force of 10 N±1N.
Each contact is tested with a straight test probe according to IEC 61032:1997, test probe D, in case of doubt with a force of 1N±0,1N.
The test probes shall not become HAZARDOUS LIVE.
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