Installation manual
Publication 1394-IN002B-EN-P — February 2004
Connecting Your 1394 SERCOS Interface System 3-5
Ungrounded Power Configuration
The ungrounded power configuration does not allow for a neutral 
ground point. If you determine that you have ungrounded power 
distribution in your plant, you need to move the factory installed 
jumper to the ungrounded power distribution position to prevent 
electrostatic buildup inside the 1394. Refer to the instructions on 
page 3-6 for 5 and 10 kW system modules, and starting on page 3-7 
for 22 kW system modules.
Figure 3.2
Ungrounded Power Configuration
Note: The input power terminal designated PE is electrically common 
to the system module single point bond bar.
Status
U
V
W
DANGER
RISK OF ELECTRICAL SHOCK. HIGH VOLTAGE MAY
EXIST UP TO FIVE MINUTES AFTER REMOVING POWER.
SERCOS System Module
PE2
W1 
V1 
U1 
PE1
1326 or MP-Series 
motor power cable
Cable clamp around shield
Bonded cabinet ground bus
Conduit/4-Wire Cable
Ground grid or
power distribution ground
System module 
single point bond bar
Shield
ATTENTION
!
Ungrounded systems do not reference each phase 
potential to a power distribution ground. This can 
result in an unknown potential to earth ground.










