168
Table 4.5
24
25
25
30 32
42
48
50
50
60 63
3 32
100 100
110
120
125
150 160
220 250
110-220
120 240
250 125
300 320
220 440 500 250
600 630
480 960 1000 500
1. systems
(based VDE 0110-1)_______________________________________
Nominal voltage
o the
supply system
For insulation
line-to-line11
For insulation
line-to-earth"
All systems three-wire-systems
mid-point earthed
V V
12. d.c. This because the actual voltage to
earth determ ined the insulation resistance and capacitive reactance each
line-to-earth; thus, low (but acceptable) insulation resistance one line can in
effect earth and raise the other two line-to-line voltage earth.19: Single-phase three two-wire a.c.000 1,000
1) Line-to-earth insulation level unearthed pedance-earthed system equals
that line-to-line because the operating voltage earth any line can, in
practice, approach line-to-line voltage.5 12.
