electrical - Wiring a Junction Box: 1 source in, 2 sources out - Home Improvement Stack Exchange
11 Types of Electrical Boxes and How to Choose One
LeMotech ABS Plastic Dustproof Waterproof IP65 Junction Box Universal Electrical Project Enclosure White 3.9 x 3.9 x 2.8 inch (100 x 100 x 70 mm) - Amazon.com