Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 52)

Publication GMC-RM001A-EN-P — July 2001
5-6 Filtering Noise
Figure 5.5
Line filter earth leakage path
Three phase filters are theoretically balanced so the net ground
current should be zero. However, a failure of any one capacitor or
severe unbalance would cause ground current to flow and trip a
circuit breaker.
Earth Leakage/Ground Fault
Earth Leakage Circuit Breakers (ELCB) and Ground Fault Interrupters
(GFI) are typical European and US terms for the same device.
The ground/earth current may cause nuisance tripping of Earth
Leakage Breakers. Uprated units may help in some cases.
Three phase filters, being balanced, are much less likely to give
problems than single phase types.
Leakage current
Load Line
L
N
E