If you are running Romex through drilled holes in floor joists or running it along the sides of floor joists and beams - the interval is every 4-1/2'. If you are entering an outlet box where the cable is held in the box by a connector or internal cable clamp, it must be fastened within 12" of the box.
It's always best to follow the 1 1/4 inch rule of thumb when installing electrical cable. Spacing can either make or break a successful electrical installation. 2) Non metallic sheathed cables should be secured within 12 inches of a box (junction box) and every 4 1/2 feet.
One of the requirements for permanent wiring, and thus for temporary wiring, was the need for adequate support. Article 336-18 stated that cable must be secured in place at intervals not exceeding 4.5 feet (1.37 m) and within 12 inches (305 mm) from every cabinet, box, or fitting.
Romex Wiring Support, NEC 336-18: Stapled, in a manner that does not damagethe cable, within 12" of electric boxes; every 4-1/2 ft. intervals, and clamped to box. Cables run through holes in studs, rafters of floor joists are considered supported at those points.
They should be just enough to hold the cable in place, but not so tight as to pinch the cable.
The code specifies that the cable length between the entry point and closest support must not exceed 18 inches. If a staple is placed 12 inches from the box, your allowable slack (or service loop) can be up to 6 inches.
According to the National Electrical Code (NEC), which is commonly followed in the United States, the requirements for securing and supporting Romex wire are outlined in Article 334.30. The code states that Romex wire must be securely fastened within 12 inches of where it enters a box, cabinet, or conduit.
1/2 in. Steel Staples for 14/2, 12/2 and 10/2 Non-Metallic Cable (500-Pack)
By code, you must leave access to any splice anywhere. (The only exception is an irreversible crimp on a service entrance cable — a special case requiring an expensive crimping tool.) Splices in attics and crawlspaces are considered accessible as long as there is a hatchway into the space.
If you are running Romex through drilled holes in floor joists or running it along the sides of floor joists and beams - the interval is every 4-1/2'. If you are entering an outlet box where the cable is held in the box by a connector or internal cable clamp, it must be fastened within 12" of the box.
334.40 is where we find the rules for securing and supporting romex. There is no mention in the NEC as to how many cables under a staple. However, many staples are listed to hold two cables or less, which would make securing three cables under those staples a 110.3(B) violation.
It is often asked whether it is fine to use a 12-gauge wire on a 15-amp circuit, and the answer is yes, it is actually fine. At 75°C, 12 AWG copper wire is ranked 25 Amps.
Noting that Romex is the name of a popular brand of Non Metallic cable, of the type specified in the NEC (US National Electrical Code) as type NM. (Like “Kleenex” is a brand of facial tissue.) Romex is not permitted anywhere that it is exposed to risk of damage, to water (dampness), and/or to sunlight.
The general rule for NM cable is to secure the cable within 12 inches of the box and every 4.5 feet thereafter. The previous code language could technically allow an unlimited length of coiled up NM cable inside the wall as long as it was secured within 12 inches of the box.
In use for far longer than PVC versions, metal electrical boxes are super-strong, fireproof, and incapable of melting. They offer the greatest level of security for electrical wiring applications. It's also virtually impossible to crush or bend a metal junction box!
Romex needs to be stapled to studs during rough framing so it doesn't get damaged by hanging drywall. Once the walls and trim are up, if romex needs to be run through a wall cavity, it does not require fastening.