Page 595 - Wago_Rail-MountedTerminalBlockSystems_Volume1_2015_US.pdf

14

593

Table F.3b - Single-Phase, 4- or 3-Wire AC Systems Material Groups
Insulating materials are classified into
four groups according to their CTI (Com-
Voltages for Table F.4 parative Tracking Index) as follows:

Nominal voltage of the For insulation For insulation Material group I: 600 ≤ CTI
supply system (mains) * line-to-line 1) line-to-ground 1)
Material group II: 400 ≤ CTI < 600
All systems Three-phase 4-wire Three-phase 3-wire Material group IIl a: 175 ≤ CTI < 400
systems systems non-grounded Material group III b: 100 ≤ CTI < 175
1)
neutral grounded 2) or corner grounded
The CTI values above refer to values
obtained in accordance with DIN EN
60664-1 / VDE 0110, Part 1 on sam-
V V V V ples specially made for this purpose and
60 63 32 63 tested with Solution A.
110
120 125 80 125
127
150 ** 160 160
200 200 200
208 200 125 200
220
230 250 160 250
240
300 ** 320 320
380
400 400 250 400
415
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) Line-to-earth insulation level for non-grounded or impedance-grounded systems equals that for line-to-line, as the
operating voltage to ground of any line can, in practice, approach full line-to-line voltage. This is because the
actual voltage to ground is determined by the insulation resistance and capacitive reactance of each line to
ground; thus, low (but acceptable) insulation resistance of one line can in effect ground it and raise the other two
to full line-to-line voltage to ground.
2) For equipment used on both three-phase 4-wire and three-phase 3-wire systems, grounded and non-grounded,
use only the values for 3-wire systems.
* For the relationship to rated voltage see 4.3.2.
** These values correspond to the values given in Table F.1.

14