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Electrical connection
6.2 Connecting the machine
6.2.1.4
Documenting holes in the terminal box
Note
Have additional holes in the terminal box with type of protection Ex d made only by the
manufacturer or by a specialist workshop for electrical machinery authorized by the
manufacturer.
Making holes in the terminal box
If you drill holes in the terminal box for explosion-protected motors, then document the data
about these holes in the motor documentation:
● Number and size of the holes
● Type of thread, e.g. metric or NPT
Data regarding the installation of pipes and accessories is provided in IEC / EN 60079-14.
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.
6.2.1.5
Cable entry
Certified cable entries, thread adapters and sealing plugs
Only use sealing plugs, cable entries and conductor entries or thread adapters that are
suitable, certified and marked for use in the respective explosion protection type and degree
of protection (DIN EN 60079-14).
Terminal box
The number and size of the cable entry tapped holes is provided in the machine dimension
drawing.
68
Operating Instructions, 03/2018, A5E41926185A
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