Okay, let's break down these questions. Remember, I am not an electrician, and this is not a substitute for advice from a qualified electrical contractor familiar with local codes. You need to consult with one before finalizing your plan. That being said, I can give you a general understanding based on NEC and common practices.

Key Considerations Before Answering



Local Codes and AHJ (Authority Having Jurisdiction)

Local codes can be more restrictive than the NEC. Always check with your local building department or inspector for specific requirements.

Commercial vs. Residential

Retail environments are commercial spaces, and the NEC has different rules for commercial vs. residential applications.

Voltage Drop

With long runs of LED tape, voltage drop is a huge concern. You'll need to calculate voltage drop to ensure the LEDs at the end of the run receive sufficient voltage. This calculation will influence your wire gauge choices.

Total Load and Branch Circuit Size

Ensure the total wattage of your LED strips on each power supply doesn't exceed 80% of the power supply's rating for continuous use. Also, make sure your branch circuit breaker is appropriately sized for the load.

Accessibility

All electrical components need to be accessible for maintenance and inspection.

Answers to Your Questions


Power Supply (Class 1) Wiring to Decoder



NEC 300.11(A) requires that wiring methods must support the wiring based on the installation requirements. The NEC is performance based, and it will be up to the AHJ to determine if the proposed wiring method is acceptable. Typically, yes, conduit (or other approved raceway) is required for the line voltage wiring to the power supply. The Class 1 classification means it is likely operating at the same voltage as the mains. It will need to be protected appropriately. Flexibility

Flexible metal conduit (FMC) or liquid-tight flexible metal conduit (LFMC) can be used in certain situations (e.g., for short runs to equipment that needs to be moved/adjusted). However, the AHJ has final say.

Wire Type

Use the appropriate wire type for the application (e.g., THHN/THWN within conduit).2.

Decoder Device



Yes, decoders, particularly those handling power distribution and control signals, should be installed in a junction box. This protects the connections, provides strain relief, and helps contain any potential faults. NEC 314 covers outlet, device, pull, and junction boxes. The box must be sized appropriately for the number of conductors entering it. Material

The box material (metal or nonmetallic) depends on the installation conditions and local codes. Metal boxes must be grounded.3.

Decoder to LED Strip Wiring



Generally, these wires do not require conduit, but it depends on the environment and the wire type. Low-Voltage Wiring

Since these wires are carrying low-voltage DC (24V), they fall under NEC Article 725 (Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits).

Wiring Methods

Article 725 allows for wiring methods appropriate for the voltage and current involved. You can use cable types like CL2, CL3, or CM (Communications Multipurpose Cable).

Exposed Wiring

If the wiring is exposed and subject to physical damage, it must be protected. This could mean using conduit, surface raceway, or a more robust cable type. In a retail environment, exposed wiring is almost always subject to damage.

Consider

Using a listed low-voltage cable management system (e.g., Panduit Pan-Way) might be a good compromise between conduit and exposed wiring, especially in a retail setting.4.

Bridging Wires Between Strips



Same as above. The wiring between strips is low-voltage, so the need for conduit depends on the environment, the wire type, and the risk of physical damage. Neat and Professional

In a retail environment, exposed bridging wires look unprofessional and are a trip hazard. Consider using a flexible conduit or raceway to protect these wires and create a cleaner look.

Wire Gauge

Ensure the wire gauge is sufficient for the current and distance to avoid voltage drop.

Side Questions

A.

UL Listing/Recognition



UL Listing is highly recommended (and often required by code) for most electrical components. UL Listing means a product has been tested and certified to meet safety standards. UL Recognition

UL Recognized components are meant to be used inside a larger UL Listed product. They are not intended for stand-alone use in the field.

Power Supplies

Definitely use UL Listed power supplies.

LED Strips

UL Listing is important for LED strips, especially in commercial applications. It ensures they meet safety standards for fire resistance, heat dissipation, and electrical insulation.

Decoders

UL Listing is important for decoders.

Wire

The wire used must be appropriate for the application and UL Listed.B.

Non-UL Listed Components in UL Listed Junction Box



Generally, this is NOT acceptable as a workaround for UL Listing. Simply putting a non-UL Listed component in a UL Listed junction box does not make it compliant. The entire assembly needs to be evaluated. Exceptions

There might be very specific cases where the AHJ allows it if the component is deemed to be sufficiently safe and the junction box is only providing physical protection, but this is rare.C.

Entire System UL Listing



It's impossible to get a "whole system" UL listing in the field. UL Listing applies to individual products. Compliance

The goal is to use UL Listed components that are installed in accordance with their listing and with the NEC. The AHJ will inspect the installation to ensure it meets code requirements.*

Responsibility

Ultimately, the electrical contractor is responsible for ensuring the installation is code-compliant.

Recommendations


Engage a Qualified Electrical Contractor

This is the most important step. They can assess the site, understand the local codes, and ensure a safe and compliant installation.2.

Use UL Listed Components

Prioritize UL Listed components whenever possible.3.

Consider a Low-Voltage Cable Management System

For the wiring from the decoders to the LED strips, a cable management system can provide protection, organization, and a professional appearance.4.

Calculate Voltage Drop

Accurate voltage drop calculations are critical for long LED strip runs.5.

Document Everything

Provide clear documentation to the electrical contractor, including wiring diagrams, component specifications, and installation instructions.

In summary: While you may have a vision for the LED lighting system, it is crucial to collaborate with a licensed electrician who can ensure the installation is safe, code-compliant, and meets the specific needs of the retail environment. Failure to do so could result in safety hazards, code violations, and potential liability. Flag for review