Insulating material group
I 600 CTI
II 400 CTI 600
III 175 CTI 400
III 100 CTI 175
The comparative tracking index must
be determined using special samples
produced for this purpose with test
solution compliance with IEC 60112
(DIN IEC 60112/DIN VDE 0303-1).e. the symbol indicates 4-wire 3-phase
distribution system.Electrical data
Design clearances and creepage distances
in electrical equipment influencing factors
Rated voltage
The rated voltage derived from the
nominal voltage the power supply
and the corresponding network type. This because the actual voltage earth determined the
insulation resistance and capacitive reactance each phase earth; thus,
a low (but acceptable) insulation resistance one phase can earth and
raise the other two full phase-to-phase voltage earth. earthing
V V
12.
*) It assumed that the rated voltage the electrical equipment not lower
than the nominal voltage the power supply.5 12.
2) For electrical equipment for use both 3-phase 4-wire and 3-phase 3-wire
supplies, earthed and unearthed, use the values for 3-wire systems only. Where only one value is
indicated, refers 3-wire 3-phase systems and specifies the value
phase-to-phase.18 1282250000 2012/2013
.
**) Because the common changes, the meaning the symbol has
not been used table i. The lower value the phase-to-neutral voltage, while
the higher value the phase-to-phase voltage.5 –
24 –
30 –
42 50**) –
60 –
30–60 32
100**) 100 –
110 120 125 –
150**) 160 –
220 250 –
110–220 250 125
120–240
300**) 320 –
220–440 500 250
600**) 630 –
480–960 1000 500
1000**) 1000 –
3-phase
3- 4-wire systems
Rated voltage
of the power
supply (mains)*)
Voltages for table 4
For insulation
phase-to-phase
For insulation
phase-to-earth
All systems 3-phase
4-wire systems
with earthed
neutral wire2
)
3-phase
3-wire systems
unearthed1
) or
phase-earthed
V V
60 63
110/120/127 125 125
150**) 160 160
208 200 125 200
220/230/240 250 160 250
300**) 320 320
380/400/415 400 250 400
440 500 250 500
480/500 500 320 500
575 630 400 630
600**) 630 630
660/690 630 400 630
720/830 800 500 800
960 1000 630 1000
1000**) 1000 1000
1) Phase-to-earth insulation levels for unearthed impedance-earthed
systems are equal those phase-to-phase because the operating
voltage earth any phase can, practice, reach full phase-to-phase
voltage.
Insulating material group
The insulating materials are divided
into four groups depending the
comparative figures for creepage
distance (CTI comparative tracking
index):
Single-phase
2- 3-wire systems
Rated voltage
of the power supply
(mains)*)
Voltages for table 4
For insulation
phase-to-phase1)
For insulation
phase-to-earth1)
All systems 3-wire systems
neutral pt. The values given table are still taken into account in
tables and the symbol.
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Technicalappendix
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