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Knockout and Clearance Diameter Machine Terminal Boxes NEMA
Electric Motors Design and Engineering
Knockout and Clearance Hole Diameter Machine Terminal Boxes per NEMA
The NEMA diameter of the knockout, excluding any projection of breakout ears or tabs, and the clearance hole in the terminal box of a machine shall be in accordance with the following:
Conduit Size, Inches |
Knockout or Clearance Diameter, Inches |
||
Nominal |
Hole Minimum |
Maximum |
|
1/2 |
0.875 |
0.859 |
0.906 |
3/4 |
1.109 |
1.094 |
1.141 |
1 |
1.375 |
1.359 |
1.406 |
1-1/4 |
1.734 |
1.719 |
1.766 |
1-1/2 |
1.984 |
1.969 |
2.016 |
2 |
2.469 |
2.453 |
2.500 |
2-1/2 |
2.969 |
2.953 |
3.000 |
3 |
3.594 |
3.578 |
3.625 |
3-1/2 |
4.125 |
4.094 |
4.156 |
4 |
4.641 |
4.609 |
4.672 |
5 |
5.719 |
5.688 |
5.750 |
6 |
6.813 |
6.781 |
6.844 |