DSH 439 Connectors and Openings
http://decisions.iecee.org/icons/ecblank.gif DSH 439
Connectors and Openings
2.1.1.1
60950(ed.2);am1-am4 & 60950(ed.3)
Standard:
IEC 950 (1991) 2nd ed.,
Amdts.1(1992), 2(1993),
3(1995), 4(1996);
IEC 60950, 3rd edition (1999)
Sub clause:
2.1.1.1
Sheet No.
439
Subject:
Connectors and Openings
Key words:
Contact with hazardous
voltages, test finger
Decision taken at the
39th meeting 2002
Question:
Is it the intent of the fourth dash of Clause 2.1.1.1 which reads “-functional or basic insulation of
parts or wiring at hazardous voltages” to include a 2 mm air gap of clearance from the tip of the test
finger since that dash says “basic insulation” and 2mm or clearance is basic insulation? A
subassembly of IT equipment (e.g., uninterruptible power supply) has modular power supplies that
are located in operator accessible compartments and are removable by the user. If the power
supply is removed, the supply connector becomes exposed within the compartment. It is not
permitted to make a contact with a hazardous voltage not exceeding 1000 volts a.c. or 1500 volts
d.c. Is this requirement sufficient or is there a need for an additional gap between the part at
hazardous voltage and the tip of the test finger figure 19 of IEC 950 (figure 2A in IEC 60950)?
Decision:
Contact is verified by means of a test finger, figure 19 of IEC 950 (figure 2A of IEC 60950), which
shall not contact parts described above when applied to openings in the enclosure (compartment)
after removal of parts that can be detached by an operator, including fuseholders, and with operator
access doors and covers open. It is permitted to leave lamps in place for this test. Connectors that
can be separated by an operator, other than plugs and socket -outlets complying with 60083, IEC
60309 and IEC 60320 shall also be tested during disconnection. Where contact is not permitted in
the above tests, there is no requirement for a minimum air gap between the tip of the test finger and
the part at a hazardous voltage not exceeding 1000 V a.c or 1500 V d.c.
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