scarygood536
New Member
Definitions
Electrical Metallic Tubing (EMT)- A unthreaded thin walled raceway designed for protection and routing of conductors and cables. For use as an equipment grounding conductor when installed appropriate fittings. EMT is generally made of steel with protective coating or aluminum
Listed Requirements
EMT, factory elbows, fittings shall be listed by the underwriters Labratory
Installation
EMT is permitted for both exposed and concealed work
All supports, bolts, straps ,screws shall be corrosive resistant materials
Uses not permitted
Where Subject to sever physical damage.
Protected from corrosion solely by enamel
In cinder concrete or cinder fill where subject to permanent moister unless protection on all sides by a layer of non-cinder concrete at least 50mm thick or unless the tube is at least 450 under the fill
In any hazardous location except as permitted by the NEC
For support of luminaries or other equipment except conduit bodies no larger than the trade size of the tubing
Dissimilar metals in contact with anywhere in the system shall be avoided to avoid galvanic action
Size
Minimum- EMT smaller than trade size ½ inch cannot be used
Maximum-EMT bigger than trade size 4 shall not be used
Bends- How Made
Bends shall be made so the tubing is not damage and the internal diameter is not effectively reduced.
Number of Bends
Reaming and threading
All cut ends of EMT shall be reamed or removed of rough edges
EMT shall not be threaded
Securing and supporting
EMT shall be fastened at least every 10ft
Couplings and connectors
Couplings and connectors shall be made up tight. Where buried in masonry or concrete, they shall be concrete tight
Grounding
EMT shall be permitted as an equipment grounding conductor
Construction
Marking
EMT shall be clearly and durably marked at least every 10 ft as required in the first sentence of 110.21
Electrical Metallic Tubing (EMT)- A unthreaded thin walled raceway designed for protection and routing of conductors and cables. For use as an equipment grounding conductor when installed appropriate fittings. EMT is generally made of steel with protective coating or aluminum
Listed Requirements
EMT, factory elbows, fittings shall be listed by the underwriters Labratory
Installation
EMT is permitted for both exposed and concealed work
All supports, bolts, straps ,screws shall be corrosive resistant materials
Uses not permitted
Where Subject to sever physical damage.
Protected from corrosion solely by enamel
In cinder concrete or cinder fill where subject to permanent moister unless protection on all sides by a layer of non-cinder concrete at least 50mm thick or unless the tube is at least 450 under the fill
In any hazardous location except as permitted by the NEC
For support of luminaries or other equipment except conduit bodies no larger than the trade size of the tubing
Dissimilar metals in contact with anywhere in the system shall be avoided to avoid galvanic action
Size
Minimum- EMT smaller than trade size ½ inch cannot be used
Maximum-EMT bigger than trade size 4 shall not be used
Bends- How Made
Bends shall be made so the tubing is not damage and the internal diameter is not effectively reduced.
Number of Bends
There shall not be more than 4 quarter bends (360 degrees) between pull pointsReaming and threading
All cut ends of EMT shall be reamed or removed of rough edges
EMT shall not be threaded
Securing and supporting
EMT shall be fastened at least every 10ft
EMT shall be fastened within 3 ft of each outlet box, junction box, device box, cabinet, conduit body, or any other tubing terminationCouplings and connectors
Couplings and connectors shall be made up tight. Where buried in masonry or concrete, they shall be concrete tight
Grounding
EMT shall be permitted as an equipment grounding conductor
Construction
Factory threaded integral couplings shall be permitted. The coupling and EMT threads shall be designed so as to prevent bending of the tubing at any part of the treadMarking
EMT shall be clearly and durably marked at least every 10 ft as required in the first sentence of 110.21
