Siemens SIMOTICS FD 1MQ1, Operating And Installation Instructions

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Requirements placed on drilled holes in Zone 21/22
For applications in Zone 21 (Ex tb) or Zone 22 (Ex tc), according to EN 60079-31, the following
requirements are placed on drilled holes:
Through holes:
● The nominal diameter of the through holes for the entry may not be 0.7 mm larger than the
nominal diameter of the thread of the cable entry or connection element.
● The inside of the terminal box must have sufficient space to attach a locking nut at the cable
entry or at the connection element.
Openings with thread must have the following attributes:
● Conical thread: Without additional sealant or seals, not less than three and one half thread
turns.
● Cylindrical threads: At least five thread turns, tolerance of 6 H, even better according to
ISO 965-1. For less than five thread turns, an additional seal or sealant is required.
6.5 Inserting and routing the cables
Table 6-2 Connection technology (with cable lug / connection without cable lug)
Terminal box Connection
GT640
With cable lug (Page 83) Without cable lug (Page 84)
1XB1621
1XB1631
1XB7730
1XB7731
1XB7740
1XB7750
6.5.1 Bringing cables into the terminal box 1XB... with sealing insert with break-off ring
The 1XB1621, 1XB1631 terminal boxes can be equipped optionally with a sealing insert with
break-off ring. The connecting cable is sealed at the cable entry location using a cut-out sealing
insert and is fastened using a strain relief device.
Electrical connection
6.5 Inserting and routing the cables
SIMOTICS FD 1MQ1
80
Operating Instructions 01/2019