Special rules apply when the stove wiring runs through conduit. National electrical code requires a junction box whenever the bends and turns in a conduit exceed 360 degrees. Each time the conduit bends, pulling wire through it becomes more difficult.
An alternative to a junction box is a condulet or capped elbow. A condulet is installed where the conduit makes a turn or a "T" and has a cover that allows access to the wires.
The heavy wire gauge used for wiring electric stoves makes pulling the wire even more difficult. Some electricians will install a junction box, even if one is not required by code, to simplify wiring or make it easier to pull the wire through the conduit.
All wire splices and wire connections must be enclosed within a junction box. If the wiring for the electric stove required a splice, perhaps due to a remodeling project, the electrician would install a junction box, run the wires inside it, and make the new connections. Any box that allows wires to enter and leave and has a cover may serve as a junction box for this purpose. The most common style are metal octagons with round metal covers.
Some homes have a counter-mounted stove top with a built-in oven. The total power requirements for this arrangement are similar to a standard electric range. A common wiring arrangement has a main cable that goes to a junction box. Inside the junction box, two more wires are spliced to the main cable with one going to the oven and the other to the stove top. This arrangement provides one circuit to serve both the stove top and the built-in oven with one circuit breaker.
A junction box provides a place to make a connection. That connection might be for two wires or cables, or for pieces of conduit to join together. The number of wires allowed inside a junction box depends on the space within the box. The NEC provides specific guidelines that govern how many wires may enter and connect inside a box of a given size. Junction boxes must be exposed and never buried behind walls or inside ceilings where they can't be reached. Metal boxes must connect to the grounding system and all boxes must have covers.