User Manual

SIRIUS 3RU2/3RB3 overload relays
5.7 Connection
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
513
5.7 Connection
Connection types
The overload relays are available with the following connection types for the main and
auxiliary current paths:
● Screw-type connection system
● Spring-loaded connection system
● Ring cable lug connection system (3RU21 only) with optional terminal covers
(accessories)
Conductor cross-sections
The conductor cross-sections of the devices in the SIRIUS modular system are matched to
one another on a size-specific basis. For more information, see the chapter titled Connection
(Page 74).
Coil repeat and auxiliary switch repeat terminal
In the case of size S00 3RU21 thermal overload relays and 3RB30/3RB31 solid-state
overload relays, direct contactor mounting involves feed-through of the auxiliary switch and
coil terminals A2 on the contactor. This makes wiring much easier.
Touch protection
Please observe the information in the chapter titled Technical data (Page 536) with regard to
touch protection for 3RU21 thermal overload relays and 3RB30/3RB31 solid-state overload
relays (according to IEC 61140). Devices with screw-type and spring-loaded connection
systems are finger-safe. To achieve finger safety in the case of ring cable lug connection
systems, the addition of terminal covers (accessories) is required.