Conduit Electrical Wiring - Calculations Conduit Fill . To find the maximum number of conductors allowed in a conduit with all of the conductors of the same size and type of insulation.. Practical Electrical Wiring: Residential, Farm, Commercial, and Industrial [Herbert P. Richter, F. P. Hartwell] on Amazon.com. *FREE* shipping on qualifying offers. Comprehensive and detailed, this reference presents the critical revisions in technical topics driven by emerging technology and building-code changes. Starting with a basic overview of the National Electrical Code and its enforcement. There are few electricians in the commercial and industrial field that don't know how to bend EMT conduit with a hand bender; it is one of the primary skills necessary to acquire and perhaps the most troubling for the new electrician and is the reason for this conduit bending guide..