Is outlet box required to be mounted?

Question

I would like to know if I hard-wire an outlet from another with wire running across floor to non-mounted outlet is this considered an extension cord.

Answer 1

"Wire", eh? Romex NM/UF/SE/MH/whatever multiconductor building cable is out of the question. It's not flexible, and is made for immobile use in protected locations, like behind walls, rafters, underground or in conduit. You can't use building cable for flexible cord at all.

Even if you have proper cordage, you're not allowed to homebrew extension cords with a handi-box and some cord. Specifically, 400.8 disallows any flexible cords

• Used as substitutes for the fixed wiring of a structure.
• Run through holes in walls, structural ceilings, suspended or dropped ceilings, or floors.
• Run through doorways, windows, or similar openings.
• Attached to building surfaces.
• Concealed by walls, floors, or ceilings — or located above suspended or dropped ceilings.
• Installed in raceways, except as permitted elsewhere in the NEC.
• Used or installed in a manner that unduly exposes them to physical damage.

400.7 carves out exceptions where you are allowed to use flexible cords:

• Pendants [210.50(A) and 314.23(H)] if the cords are identified for pendant use in Table 400.4.
• Wiring of luminaires as allowed by 410.24(A) and 410.62(B).
• Connection of portable luminaires, portable and mobile signs, or appliances as allowed in 422.16 [400.7(A)(3), but when used with attachment plugs [400.7(B)].
• Elevator cables.
• Wiring of cranes and hoists.
• Connection of utilization equipment to facilitate frequent interchange [422.16], but only when used with attachment plugs [400.7(B)].
• Prevention of the transmission of noise or vibration [422.16].
• Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connections [422.16], but only when used with attachment plugs [400.7(B)].
• Connection of moving parts.
• Where specifically permitted elsewhere in the NEC.

Answer 2

I think for it to be considered an extension cord, it would need a male plug at one end (it has to be portable). Hardwiring to another outlet box or a junction box sounds more like a permanent fixture, so you would have to follow the appropriate building code for where you are installing this.

That said, the 2017 NEC does allow for outlets attached to "flexible cord":

314.23 (H) Pendant Boxes. An enclosure supported by a pendant shall comply with 314.23(H)(1) or (H)(2)

(1) Flexible Cord. A box shall be supported from a multiconducter cord or cable in an approved manner that protects the conductors against strain, such as a strain-relief connecter threaded into the box with a hub.

However, this is within the context of hanging fixtures. The bigger problem with your proposed installation is running the cord along the floor - it's going to be subject to foot traffic there, which would create a trip hazard and cause wear. I wasn't able to find any approved examples of this scenario in the NEC.

Answer 3

This is in addition to @CactusCake. First, if you hardwire into an outlet, by definition it cannot be an extension cord. Second, Since it is attached to the internal circuitry of a building it has to meet and be approved as part of the wiring system.

Since you didn't specify any particular type material I cannot give you a direct answer to whether or not it would be allowed, But the material you are using can be found in Chapter 3 of the NEC "Wiring Methods and Materials". For example let's say you wanted to use type NM cable for the conductors. Then you would be referred to Article 334.15 (B) "Protection from physical damage" and see you couldn't use that material.

Third I am against any method of having live circuitry just lying around on a floor exposed to damage and other hazards. In my opinion it simply isn't a safe installation.

Hope this helps.