The
clearance distances IEC 60947-1 and IEC 60664-1 are
related it.
Rated impulse withstand voltage IEC 60947-7-1
Rated impulse withstand voltage the peak value surge
voltage with which the terminal blocks can subjected. This serves reference for certain thermal,
mechanical and electrical requirements.5 2.75 1.) This applies exclusively to
terminal blocks with multiple connection levels (multi-tier
terminals) and test-disconnect terminal blocks for which
current reduction permissible.
Terminal blocks have rated connection capacity
that least two levels lower than the rated cross-
section.5 0.2. The rated cross-
section selected from the following standard cross-
sections: 0.
The verification the rated cross-section performed
with gauges according IEC 60947-1.33
3029140000
Installation
C
Standards and industries
.
Pollution severity IEC 60947-7-1
The pollution severity defines the influence solid, liquid or
gaseous foreign matter, which may reduce the dielectric
strength the specific surface resistance.2 0. Pollution
severity has been specified for terminal blocks for industrial
applications: conductive contamination occurs dry,
non-conductive contamination which becomes conductive
as moisture condensation may also occur.0 –
16 120 150 240 300 mm2
.Technical requirements from the standards
Rated cross-section
The rated cross-section terminal block the value of
the connectable wire cross-section, specified the
manufacturer.
Rated current IEC 60947-7-1
Test currents are assigned the rated cross-sections
according IEC 60947-7-1.0 6.5 4. These rated currents cause
no impermissible heat transfer the terminal:
mm2
1.
Rated voltage IEC 60947-7-1
The rated voltage terminal block the rated insulation
voltage which the insulation tests and creepage distances
relate.5 4.5 2.3.
Operating conditions
The terminal blocks can operated under
the following normal conditions:
• Ambient temperature +40 °C,
mean value +35 °C
• Altitude 2000 above sea level
• Relative humidity: +40 °C, +20 °C
C. The conductors can solid, stranded or
flexible, possibly with conductor end pretreatment.5 41
mm2
10 35
A 101 125
mm2
50 120
A 150 192 232 269
mm2
150 185 240 300
A 309 353 415 520
Conventional free-air thermal current (Ith)
The conventional thermal current free air (Ith) the
highest test current for heating tests unenclosed devices
(see 4.0
A 17. determined analogously IEC 60664-1.0 1.0 6. The minimum air
clearance measurement defined IEC 60947-7-1 in
conjunction with the rated surge voltage.1 lEC 60947-1
