The maximum number of 12-gauge wires you can put in a 3/4 inch conduit is 16. This figure includes all the neutral wires and the ground wire. An electrical conduit is a piping system that is used for the protection and the routing of electrical wiring. A conduit can be made of a number of materials including metal, plastic and fibre. There is also a special flexible conduit available for special purposes. Electricians install the conduit when electrical equipment is being installed. The NEC (National Electrical Code) is the standard for safe installation of electrical equipment and wiring in the United States. The NEC is available as a book with over 1,000 pages and is updated every three years. It is also available online and this version is also updated regularly. The NEC has a section on conduit wiring, which states that wiring can be installed directly into walls in most buildings, although commercial and industrial buildings need the conduit to protect the wiring from damage. An alternative to conduit in these buildings is ductwork made of metal or plastic. The main concern with conduit, according to NEC, is that there may be damage to the wire caused by kinks or excess pulling. A wire that breaks inside a conduit will be lot more expensive and time consuming to replace, as the entire conduit will also need to be replaced. The NEC specifies safe measures to protect the wire from damage, both during and after installation. Everyday conduit is not watertight so in wet locations there will be a special conduit required. This is a standard threaded pipe with openings to keep moisture out. If the conduit is being used in an area with dangerous gases then further protection is needed to protect from ignition of the gases. This protection is in the form of gas-tight barriers.
I will try this again (something went wrong with the transmission of my first answer). My code book is at the office but I believe the answer is 16. HOWEVER, if you put 4 or more current carrying conductors (hots and neutrals) in a conduit, you must do what is called derating which means upsizing your conduit or wire. Typically, we don't put mor than 2 full boats of #12 gauge wire into a 3/4" inch conduit which consists of the following nine - #12 gauge wires: 2 blacks, 2 reds, 2 blues, 2 whites and 1 green. In the industry, a full boat is all three phases (in a three phase system) black, red, blue (all hot wires) white (neutral) and green which is your ground.
Hope this helps
Hope this helps
How many 12 gauge wires can you install in 3/4 inch pvc conduit.