Amazon.com: Structural Pipe Fitting, DIY Outdoor, Use Imagination -1-1/2"Tee-E Short, 3T-8, Aluminum Magnesium, Note: ID of fitting is 1.925, to take nominal 1-1/2" steel pipe which all have an OD of 1.9". :
Commercial Electric 1-1/2 in. Electrical Metallic Tubing (EMT) Set-Screw Coupling FEPSS-150-1 - The Home Depot
Insulated Steel EMT Connector Set Screw Type Pipe Fitting Raintight Connectors Conduit Terminals - China Insulated EMT Terminals, EMT Connector | Made-in-China.com