You're right to be concerned about the proper connectors for your 0-10V control wiring in a drop ceiling. Let's clarify the situation and explore your options

Understanding the Requirements
NEC (National Electrical Code)

The NEC is the governing standard for electrical installations. It emphasizes safety and proper installation methods.

Securing Cables

All cables must be securely fastened to enclosures (like your fixture's junction box) to prevent strain on the connections and ensure the integrity of the wiring.

Class 2 Circuits

0-10V dimming control circuits are generally considered Class 2 circuits. Class 2 circuits are power-limited and are considered safer than general branch circuits. However, this doesn't mean they can be ignored regarding proper installation.

Strain Relief

Connectors are primarily for providing strain relief, preventing the wires from being pulled out of their terminals.

Why the Plastic Bushing is Likely Not Compliant

As you suspected, a simple plastic bushing that doesn't grip or secure the cable is almost certainly not code-compliant. It doesn't provide any strain relief.

What Type of Cable is the 0-10V Wiring?

Knowing the type of cable you're using is crucial. Common types include: CL2/CL3 Cable

These are specifically rated for Class 2 and Class 3 circuits, and are common for low-voltage control wiring. They may look similar to thermostat wire or speaker wire.

Low Voltage Lighting Cable

It's important to make sure that the cable being used is rated to the correct voltage.

Other Low Voltage Cable

In rare cases the cable might be rated for the correct voltage but isn't properly secured at the connector.

Acceptable Connector Options

Since Class 2 wiring is low voltage, it does not carry the same requirements as high voltage wiring. However, the connector used must still provide adequate strain relief. The best option is to consult the local electrical inspector to determine what connector they prefer.Here are some options: Strain Relief Bushings/Cord Grips

These are specifically designed to grip the cable jacket and provide strain relief. Look for ones that are sized appropriately for the diameter of your 0-10V cable. Some are plastic, others are metal. They are easy to install, often just screwing into the fixture's knockout. This is likely the best option.

Small Cable Clamps (for Round Cable)

Similar to cord grips, these clamp down on the round cable jacket. Again, ensure the size is correct for your cable.

Romex Connectors (with limitations)

Using a Romex connector on a round, low-voltage cable is generally not the best practice. Romex connectors are designed for flat NM-B cable. Using a Romex connector for a round, low-voltage cable may not secure it properly. However, if the cable is secured properly within the connector, an electrical inspector may accept it.

Important Considerations Knockout Size

Make sure the connector you choose fits the knockout size in the fixture's junction box.

Cable Diameter

The connector must be sized correctly for the outside diameter of your cable. Too small, and it won't fit. Too large, and it won't grip properly.

Installation Instructions

Always follow the manufacturer's installation instructions for the connector.

Local Codes and Inspection

Ultimately, your local electrical inspector has the final say on what is acceptable. It's always a good idea to check with them before you do the work, especially if you are unsure.

Steps to Take1. Identify the Cable Type

Determine what type of cable is used for your 0-10V wiring (CL2, low voltage, etc.).2.

Measure the Cable Diameter

Measure the outside diameter of the cable jacket.3.

Choose an Appropriate Connector

Based on the cable type and diameter, select a connector that is specifically designed for securing round cables and providing strain relief.4.

Install Properly

Follow the manufacturer's instructions for installing the connector. Ensure the cable is securely gripped and cannot be easily pulled out.5.

Consult the Inspector (Recommended): If you are unsure, take pictures of your proposed setup and consult with your local electrical inspector before you complete the installation.By taking these steps, you can ensure that your 0-10V wiring is installed safely, correctly, and in accordance with the NEC and local codes. Proper strain relief is essential for the long-term reliability of your lighting system. Flag for review