IDEC SG4 Type 4 Finger & Hand - Manual (Page 36)

SG4-B Series Instruction Manual
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 The ground connection of the two units is not necessary for Class
III, while the use of a duly-insulated low-voltage feeder type SELV
or PELV is compulsory. In this case, we recommend covering the
earth symbol present on the caps of the two units with a blank
sticker.
 The ground connection of the two units is compulsory for Class I,
while the use of a duly-insulated feeder type SELV or PELV is not
compulsory but anyway recommended.
The following table is a summary of SG4 electrical protections.
Electrical protections Class I Class III
Ground Connection Compulsory Not necessary
Ground connection symbol Compulsory Not necessary
Power supply by generators
SELV / PELV
Recommended Compulsory