Okay, you're right to be cautious and ask! There are definitely code considerations here. Let's break this down

The Situation (Summarized):
Existing conduit embedded in concrete, now cut flush with the floor. Need to re-establish electrical connections to equipment in the same location. Conduit is 240V 3-phase and 480V 3-phase. The proposed solution is to use junction boxes where the conduit is cut, but the conduit won't directly connect to the box (wires will pass through).

Why the Junction Box Idea Has Problems (and Needs Careful Consideration)



Mechanical Protection

Conduit provides mechanical protection to the conductors. Simply having wires "flow" into a box doesn't provide adequate protection where the conduit ends. This is a major safety concern, especially with high voltages.

Strain Relief

Where the conduit ends, there's no built-in strain relief for the conductors. Over time, movement or pulling on the wires could cause them to become loose within the box, leading to potential arcing, shorts, or other failures.

Securing Conductors

Conductors needs to be supported. Unsupported conductors can cause issues.

Trip Hazard Mitigation

While a junction box might eliminate the sharp edge of the cut conduit, it could still create a trip hazard if not properly installed and protected. It also might just be a bigger, more solid thing to trip over.

Relevant NEC (National Electrical Code) Articles to Consider



300.4 Physical Protection

This is your starting point. This section requires conductors and raceways to be protected from physical damage. Cutting the conduit flush to the floor and then running wires into a box without proper protection almost certainly violates this.

300.15 Boxes, Conduit Bodies, or Fittings — Where Required

This section outlines where boxes or fittings must be used. Generally, any time you're making a splice, tap, or termination, you need a box or fitting.

314 Boxes, Conduit Bodies, and Handhole Enclosures

This entire article deals with the proper installation and use of boxes. Pay close attention to:

314.17 Conductors Entering Boxes, Conduit Bodies, or Fittings

This addresses how conductors must enter the box, including securing and protecting them. It specifically covers the use of connectors to properly terminate conduit to the box.

314.27 Outlet Boxes

Addresses outlet box usage.

314.40(D) Covers and Canopies. All boxes are required to have covers. 358 EMT and IMC Conduit Articles

Addresses the proper install and use of metal conduits.

Article 110 Requirements for Electrical Installations

110.3 Examination, Installation, and Use of Equipment.
110.12 Mechanical Execution of Work110.14 Electrical Connections.

Here's What You Need to Do (Proper Solutions)


Proper Conduit Extension/Connection

The right way to do this is to properly extend the conduit runs and connect them securely to the junction box. This will maintain the mechanical protection and grounding continuity. Here are a few options:

Examine the cut end of the conduit

Is there enough room to thread a coupling onto it? If so, you could extend the conduit upward using couplings and short sections of conduit, then connect to a properly sized junction box.

Use Listed Fittings

If threading isn't possible, there are various types of listed fittings (e.g., compression couplings designed for embedded conduit) that can be used to securely connect conduit extensions to the existing stubs. Make sure any fittings you use are rated for the conduit type (EMT, IMC, Rigid).

Concrete Removal

If the above aren't feasible, you might have to carefully chip away enough concrete around the conduit to allow for a proper connection. Be extremely careful not to damage the conduit or conductors inside!2.

Proper Grounding

Ensure proper grounding continuity is maintained throughout the extended conduit system. This is CRITICAL for safety with 240V and 480V systems. Use grounding bushings and bonding jumpers as needed.3.

Box Selection

Choose appropriately sized and rated junction boxes for the number and size of conductors. They must be NEMA-rated for the environment (e.g., dust-tight, waterproof, etc.) if required.4.

Conductor Protection

Use proper bushings and connectors to protect the conductors as they enter the junction box.5.

Trip Hazard Mitigation

Ensure the junction boxes are securely mounted and, if necessary, protected with bollards or other physical barriers to prevent accidental impact and tripping.6.

Permitting and Inspection

This work absolutely requires a permit and inspection by a qualified electrical inspector. They will verify that the installation meets all applicable code requirements.

Why the "Conduit Flowing Into Box" is Likely Wrong

The idea of simply letting the conduit flow into the box without a proper connection is unlikely* to meet code and creates a significant safety hazard. It's a shortcut that could lead to serious problems down the road.

In Conclusion:

Don't take shortcuts with electrical work, especially with high voltages. The safety of yourself and others depends on doing the job right. Consult with a licensed electrical contractor who is familiar with industrial electrical systems. They can assess the situation, propose a code-compliant solution, and perform the work safely and correctly. Flag for review