Installation Specifications - Siemens 3UG4 User Manual

13.2.5.2

Installation specifications

Note
Please ensure strict adherence to the installation specifications for live cables.
Open-circuit voltage may result in death, serious injury or material damage
The current transformer output is a constant current power supply. In accordance with
U = R * I, the output voltage increases with an increasing resistance. If the connecting
terminals of the current transformer are open, the output voltage may become high enough
for you to put your life at risk or permanently damage the current transformer.
Avoid operating the unit when open. Operating a network for monitoring safely and without
faults requires that the monitoring relay and the 3UL23 residual current transformer have
been installed completely. It is absolutely necessary to short-circuit previously installed
3UL23 residual current transformers when the units are not connected to a monitoring
relay.
3UL23 residual current transformer conductor cross-sections
In accordance with DIN EN 60204-1 "Safety of machinery", the current carrying capacity of
conductors is limited depending on their cross-section. This results in the ideally suitable
residual current transformer to be used as per the following table. Please observe potentially
deviating, local installation specifications.
Order number Bushing opening
Diameter [mm]
3UL2302-1A
3UL2303-1A
3UL2304-1A
3UL2305-1A
3UL2306-1A
3UL2307-1A
3UL23 residual current transformers for external fault current monitoring
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
WARNING
Max. conductor cross-section
3P copper cable + N [mm
35
55
80
110
140
210
13.2 Accessories for 3UG4 monitoring relays
AWG [kcmil]
]
2
25
50
150
240
2 x 185 2 x 350/400
2 x 240
Rated current per phase [A]
4
1 / 0
300
500
2 x 500
Accessories
85
150
225
400
500
630
335