IEC 60950-22:2016 © IEC 2016 – 9 –
NOTE 1 The temperature values are based on IEC 60721-3-4 class 4K2. These temperatures do not take into
account severe environments (for example, extremely cold or extremely warm), nor do they include provision for
heating by radiation from the sun (solar loading).
NOTE 2 Attention is drawn to IEC 61587-1 for additional information on performance levels C1, C2 and C3
.
NOTE 3 In Finland, Norway and Sweden, the temperature in winter can be extremely low. For OUTDOOR
EQUIPMENT
this will demand special design so that the equipment can stand transport, erection and
operation/service at temperatures down to –50 °C.
4.2 Mains supply
4.2.1 General
Mains-operated
OUTDOOR EQUIPMENT shall be suitable for the highest MAINS TRANSIENT
VOLTAGE
expected in the installation location.
Consideration shall be given to the following:
– the prospective fault current of the supply to
OUTDOOR EQUIPMENT can be higher than for
indoor equipment, see IEC 60364-4-43; and
– the
MAINS TRANSIENT VOLTAGE for OUTDOOR EQUIPMENT can be higher than for indoor
equipment.
Within a certain overvoltage category, components within
OUTDOOR EQUIPMENT that reduce the
MAINS TRANSIENT VOLTAGE or the prospective fault current shall comply with the requirements
of the IEC 61643-series.
NOTE 1 The overvoltage category of OUTDOOR EQUIPMENT is normally considered to be one of the following:
– if powered via the normal building installation wiring, overvoltage category II;
– if powered directly from the mains distribution system, overvoltage category III;
– if at, or in the proximity of, the origin of the electrical installation, overvoltage category IV.
NOTE 2 For further information regarding protection from overvoltages, see IEC 60364-5-53.
Compliance is checked by inspection of the equipment and the installation instructions.
4.2.2 Mains transient voltage on AC mains supply
Equipment that is part of the building installation, or that may be subject to transient
overvoltages exceeding those for overvoltage category II, shall be designed for overvoltage
category III or IV, unless additional protection is to be provided internally or externally to the
equipment. In this case, the installation instructions shall state the need for such additional
protection. Clearances in equipment designed for overvoltage category III or IV shall comply
with Annex G of IEC 60950-1:2005. The insulation system used in such equipment shall be
capable of withstanding the test voltage given in Table 5C of IEC 60950-1:2005/AMD2:2013.
4.2.3 Mains transient voltage on DC mains supply
The transient on a
D.C. MAINS SUPPLY depends on the source and the installation of the D.C.
MAINS SUPPLY
. When determining the D.C. MAINS TRANSIENT VOLTAGE, the installation and the
source of the
D.C. MAINS shall be taken into account. If these are not known, the MAINS
TRANSIENT VOLTAGE
on the D.C. MAINS SUPPLY shall be assumed to be 1,5 kV.
The manufacturer shall declare the
MAINS TRANSIENT VOLTAGE on the D.C. MAINS SUPPLY in the
installation instructions.