What is the smallest trade size EMT that can be installed between two large pull boxes?

The smallest trade size EMT (Electrical Metallic Tubing) that can be installed between two large pull boxes is 1/2 inch. The National Electrical Code (NEC) provides guidelines regarding the minimum size of conduit required based on the size and number of conductors to be contained within the conduit, as well as the overall fill capacity.

In scenarios involving large pull boxes, a 1/2 inch EMT is typically adequate to allow for the necessary wiring to be pulled through without exceeding fill limits. While larger sizes may be allowable, the use of the smallest size possible helps to reduce costs and space requirements. Therefore, using 1/2 inch EMT ensures that the installation meets code requirements while effectively facilitating conductor placement.

Overall, understanding conduit fill, capacity, and the physical constraints of the installation allows contractors to select the appropriate trade size that complies with the code regulations while also satisfying the installation needs.