An electrician is responsible for installing a 100 A, 240 V circuit using 3 AWG copper conductors (T90 Nylon) to a detached garage. The cable will be run underground in a trench. Considering factors like conductor type, current rating, and environmental conditions, which of the following wiring methods is the most appropriate and compliant with the CEC for direct burial in wet locations and suitable for a 100 A feeder?

Question: An electrician is responsible for installing a 100 A, 240 V circuit using 3 AWG copper conductors (T90 Nylon) to a detached garage. The cable will be run underground in a trench. Considering factors like conductor type, current rating, and environmental conditions, which of the following wiring methods is the most appropriate and compliant with the CEC for direct burial in wet locations and suitable for a 100 A feeder?

Answer options:

• NMD90 (Non-metallic sheathed cable)
• AC90 (Armoured cable)
• NMWU (Non-metallic jacketed cable for wet locations, underground) ✅ Teck90 (Armoured 'TEC' cable with integral jacket)

Correct answer: Teck90 (Armoured 'TEC' cable with integral jacket)

Explanation: Teck90 cable is specifically designed for direct burial and wet locations, providing robust mechanical protection and suitable insulation for the application. NMD90 and AC90 are not rated for direct burial or wet locations. NMWU is rated for direct burial but Teck90 offers superior mechanical protection against damage during and after installation, which is often preferred for feeders in direct burial applications.