General Requirements

All exposed steel RMC, IMC and EMT shall be run parallel or perpendicular to walls and ceilings.
A sufficient number of home run conduits / tubing shall be installed so that excessive circuit loading will be eliminated.
If home runs are to be concealed by the finish of the building (except for suspended ceilings), the minimum size of home run conduit and tubing shall be trade size 3/4.
The minimum size for steel conduit / tubing in industrial occupancies shall be trade size 3/4.

NOTE: Minimum size requirements are to provide room for future expansion of circuits in locations that are difficult to access.

Overhead service conductors shall be run in steel RMC, IMC or EMT. When used for mast installations supporting the overhead drop, EMT shall be supported by braces or guys, in accordance with NEC 225.17.
EMT shall not be used where damage severe enough to damage the conductors within is likely to occur.
Sufficient expansion fittings for the application shall be installed (see 4.3.2).
Where corrosion protection is required, field-cut threads shall be protected with an approved electrically conductive, corrosion-resistant coating. For extended service life in wet or damp environments, it may be desirable to also apply this coating to exposed factory threads after installation.
Steel conduit / tubing shall not be used to support enclosures except as permitted by the NEC.
Splices or taps shall not be made inside RMC, IMC or EMT.
All conductors and neutrals of the same circuit and all equipment grounding conductors shall be contained within the same conduit / tubing.

NOTE: This is extremely important in alternating current (AC) applications.

The conduit / tubing system shall be installed complete, including tightening of joints, from termination point to termination point prior to the installation of conductors.
Cutting and threading shall comply with Section 4.1 or Section 6.3, as applicable.
Bending shall comply with Section 4.2.
Supports shall comply with Section 4.4.