How Many T8 Lights on a 20 Amp Circuit? Things You Should Know

When it comes to lighting up space efficiently, T8 lights have become a popular choice due to their energy-saving capabilities and long lifespan. However, it’s crucial to consider the electrical capacity of the circuit to ensure safety and optimal performance. In this article, we will explore the factors to consider when determining the number of T8 lights that can be installed on a 20 Amp circuit.

Calculating Wattage and Current Draw

Before diving into the specifics, let’s briefly understand the basics. Amps, short for amperes, measure the flow rate of electric current in a circuit. A 20 Amp circuit can handle a maximum current of 20 amperes before becoming overloaded. When planning the installation of T8 lights, it’s important to ensure that the total current draw remains within this limit to prevent circuit tripping or damage.

To determine the number of T8 lights that can be safely installed on a 20 Amp circuit, we need to consider their wattage and the corresponding current draw. T8 lights typically come in various wattages, with the most common being 32 watts.

Now, P=VI

Or, I=P/V

Or, I=32/120

Or, I=0.27 amp

To calculate the current draw of a T8 light, we divide its wattage by the voltage of the circuit. In the case of a standard 120-volt circuit, the current draw of a 32-watt T8 light would be 0.27 amps.

In addition to the wattage of the light bulbs, there are a few other things to keep in mind when calculating the number of T8 lights that can be placed on a 20 Amp circuit:

• Ballast type: The type of ballast used in the light fixture can also affect the amount of current that it draws. Electronic ballasts are more efficient than magnetic ballasts, so you can place more lights on a circuit if you are using electronic ballasts.
• Other loads on the circuit: If there are other loads on the circuit, such as outlets or appliances, you will need to factor those into the equation. It is generally recommended to keep the total load on a circuit below 80% of the circuit’s capacity.

Determining the Number of T8 Lights

With the knowledge of the current draw of a single T8 light, we can now determine the number of lights that can be safely installed on a 20 Amp circuit.

To ensure safety and optimal performance, it is recommended to leave a buffer to avoid overloading the circuit. Typically, electrical professionals recommend not exceeding 80% of the circuit’s capacity. Therefore, for a 20 Amp circuit, the safe threshold would be 16 amps (20 amps × 0.8).

Considering the current draw of a 32-watt T8 light (0.27 amps), we can calculate the maximum number of lights as follows:

Max T8 Lights = Safe Threshold / Current Draw per Light

Or, Max T8 Lights = 16 amps / 0.27 amps

Or, Max T8 Lights ≈ 59

Considering Other Devices on the Circuit

It’s crucial to consider other devices or appliances connected to the same circuit. If other electrical loads are sharing the circuit, subtract their amperage from the total available amps to determine the remaining capacity for the T8 lights. Overloading a circuit can lead to overheating, tripped circuit breakers, or even electrical fires.

Professional Installation and Safety

While these calculations provide a general guideline, it’s always advisable to consult with a qualified electrician for your specific installation needs. A professional electrician can assess the existing wiring, ensure the circuit is properly grounded, and install the T8 lights safely and efficiently. 

Frequently Asked Questions

Can I install T8 lights on the same circuit as other devices like computers and printers?

To install T8 lights on a circuit, consider the combined amperage of all devices and subtract it from the total circuit capacity to avoid overloads.

Do I need a professional electrician to install T8 lights on a 20 Amp circuit?

Hire a professional electrician for T8 light installation, as they can assess wiring, ensure proper grounding, ensure safety, reduce hazards, and comply with local regulations.

Can I use T8 LED retrofit tubes on a 20 Amp circuit?

T8 LED retrofit tubes are energy-efficient and can be safely installed on a 20 Amp circuit, consuming less power than traditional fluorescent tubes, and requiring a total wattage calculation.

To Conclude

Installing T8 lights on a 20 Amp circuit is an energy-efficient option for commercial and residential spaces. To determine safe T8 fixtures, calculate total wattage, convert it to amps, and consider other devices. Prioritize safety and consult a professional electrician for a secure and reliable lighting setup.