CL2 Vs CL3 Speaker Wire (Here’s The Difference!)

The main difference between CL2 and CL3 wires is that the former has a voltage limit of 150 volts while the latter has a limit of up to 300 volts. 

However, there is more to these speaker wires than their voltage limits. Compliance with laws is also a big consideration why these wires have very specific uses. 

This in-depth comparison of CL2 vs. CL3 speaker wire is all you need to understand and set up the ultimate sound system like a pro. 

CL2 Vs CL3 Speaker Wire – The Differences


For in-wall and in-ceiling speaker connections, the wire gauge is important. However, it is not as important as choosing the wires with the right rating. 

Note: The CL in both the wires is the fire safety rating set by the government and the regulatory body, NEC, to prevent electrocution, and is specifically for copper-based speaker wires. 

CL2 is short for Class 2 speaker wire, and the wire is rated specifically for low voltage connections. According to the National Electrical Code, for residential use, CL2 wires are also marked as CL2X. 

On the other hand, CL3 wires stand for Class 3 speaker wires and are also rated for low voltage connections. However, CL3-rated speaker wires have twice the voltage limit as their counterpart, and CL3 wires for residential use are also marked as CL3X.


Both CL2 and CL3 speaker wires are designated safe for in-ceiling and in-wall speaker wiring. 

So apart from powering a home sound system, these speaker wires are passed safe for running such appliances as remote controls, audio/video interconnects, HDMI cables, and Cat5/6. In addition, CL2 and CL3 wires are also used to power low-voltage appliances at home, such as a ceiling fan. 

To pass the Underwriters Laboratory testing, CL2 and CL3 must pass one of the two tests, usually chosen by the wire manufacturer. UL tests typically involve flame testing, thereafter evaluating the damage caused to the wire by the fire. 

Running speaker/audio wires that does not have the proper fire safety rating can cause the wire to burn out and result in fire, causing loss to property and lives. 

The designation of the speaker wires is paramount while wiring homes for a couple of reasons:

  • Construction inspectors check this designation on the wires to make sure it is safety compliant. 
  • Speaker wire that has a CL2/CL3 designation on the outer jacket also gives a clean look irrespective of how many appliances are installed. 
  • The CL2/CL3 designation also ensures fire safety requirements in the building. 

Voltage specification 

The voltage specification in CL2 and CL3 is the main difference between the two wires. Although both the speaker wires are rated for low voltage connections, CL2 has a voltage limit of 150 volts, which is typically the voltage limit in most residential homes.

CL3, on the other, has twice the voltage rating that of CL2 since it can handle up to 300 volts. 

Within the voltage range of 150 to 300, CL2 and CL3 speaker wires can be used safely without the risk of burning and causing a fire, even if there are sudden power fluctuations and surges. 

CL3 speaker wires can safely substitute CL2 for audio and other low voltage connections without any safety issues. 

However, CL2 speaker wires cannot be used for wiring in place of CL3. 

CL2 speaker wires offer a low level of protection from electric shock and electrocution, according to NEC 725.2. However, between the two wires, CL3 has more level of protection from electric shock since it is rated to handle more voltage. 


Using proper cables is critical for safety, performance, and compliance factors. Whether it is for an outdoor speaker system or an indoor setup, CL2 or CL3, is not only safe and complies with the safety standards. They usually are in the standard voltage range of most homes and amplifiers. 

CL2 and CL3 audio wires have similar functions and features since they both are designated for low voltage wirings. However, the voltage capacity of CL3 is higher, and it can be used in the place of CL2 but not the other way round as it will be unsafe. 

Therefore, taking the rating of the CL2 and CL3 speaker wires is the most important thing to keep in mind while selecting your wiring system. 

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