When installing LED lighting, it is common to have line-voltage wiring on one side of a power supply and low-voltage wiring on the other. The challenge comes when both types of wiring need to enter the same electrical box, enclosure, or device. This is where proper circuit separation becomes important.
The National Electrical Code (NEC) has specific requirements for how different circuit types can be installed together. The goal is straightforward: keep conductors with different voltage levels properly separated unless the wiring methods being used meet the requirements that allow them to share the space.
For LED lighting installations, this is especially important when a power supply, driver, dimmer, or controller is installed in a junction box or wall box.
Why does line voltage need to be separated from low voltage?
Line-voltage wiring carries significantly more electrical energy than typical low-voltage LED wiring. If the two systems are allowed to contact each other because of an improperly routed conductor, damaged insulation, or a loose connection, the low-voltage side could be exposed to a voltage it was never designed to handle.
Separation helps reduce the risk of accidental contact and makes the installation easier to understand and service later.
The NEC has specific requirements for how different types of circuits can be installed together. Article 724 covers Class 1 power-limited circuits, while Article 725 covers Class 2 and Class 3 circuits, including requirements for keeping them separated from line-voltage and other circuits. The exact requirements depend on the wiring method, enclosure, cable type, and other installation details.
That is why you cannot simply assume that because an LED circuit is "low voltage," its conductors can be placed anywhere.
What does an isolation plate do?
An isolation plate, sometimes called a barrier or divider, creates a physical separation between different wiring compartments inside an enclosure.
Think of it as a wall inside the electrical box. Line-voltage conductors stay on one side, while the low-voltage conductors remain on the other.
This can be particularly useful when installing an LED driver or dimmer in a wall box where both the incoming line voltage and outgoing low-voltage wiring are present.
For example, the InDrive 2-in-1 Dimmer Switch + Driver includes an isolation barrier plate designed to separate the high-voltage and low-voltage areas within a single-gang box. The plate can also be adjusted to accommodate different wiring orientations and available space.
The important takeaway is that the barrier is not simply there to make the installation look organized. It provides a physical means of maintaining separation between the different circuit conductors.
Using an InDrive isolation plate
The InDrive is a good example of how circuit separation can be incorporated directly into an LED lighting product.
During installation, the isolation barrier plate is installed inside the wall box to create separate areas for the line-voltage input and the low-voltage output. The plate can rotate to accommodate different wiring configurations, and it can be shortened for certain shallow-box installations.
This makes the installation more straightforward because the separation is built into the installation process rather than requiring the installer to figure out how to create a divider on their own.
Always follow the product's installation instructions along with the NEC and applicable local requirements.
What about a power supply with an integrated junction box?
Another way to simplify line and low-voltage separation is to use a power supply enclosure that is designed with separate wiring areas.
For example, VersaDrive power supplies are available in different configurations, including Class 2 models (VersaDrive 96 Watt Power Supply and VersaDrive 288 Watt Power Supply) and higher-output Class 1 models (VersaDrive 300 Watt Power Supply). The classification matters because the wiring and installation requirements can change depending on the power supply and circuit.
An enclosure designed specifically for an LED power supply can provide dedicated areas for making input and output connections. We also offer power supply junction box enclosures with sections on opposite ends for connections on the input and output sides of the power supply.
This type of design helps keep the wiring organized and reduces the chance of line-voltage and low-voltage conductors being mixed together.
What should you look for during an installation?
Before putting everything into a junction box, take a moment to identify what each conductor is carrying and how the circuit is classified. Don't rely solely on the fact that the wire is connected to an LED light.
Check the following:
- The power supply's output classification
- The wiring method being used
- The requirements for the specific enclosure
- The installation instructions
If different circuit types share an enclosure, verify whether a barrier, spacing, raceway, or another permitted wiring method is required.
For DIY projects, this is also a good place to know when to call an electrician. Working with line voltage is not the same as simply connecting an LED strip, and local electrical codes may have additional requirements.
Keep the two sides separate
Whether you are installing an LED driver behind a wall switch, wiring an under-cabinet lighting system, or connecting a larger commercial LED installation, keeping line voltage and low voltage properly separated is an important part of a safe, code-compliant installation.
Products such as the InDrive isolation plate and properly designed power supply enclosures can make that separation much easier to achieve. The key is to understand the circuit classification, use an appropriate wiring method, and follow both the NEC and local code requirements.
When in doubt, separate the circuits and check the code before energizing the system.
