How Are CL2 And CL3 Speaker Wires Different? – Noisylabs

The “CL’s” is an abbreviation for classification.

So it’s natural to think CL3 speaker wires are rated higher than CL2 wires.

But the question is, what are these specific wires used for?

These wires are specifically used for running wires through walls and ceilings.

But there’s more to this then where they go, there’s also a compliance issue which is another reason why these speaker wires are used.

For a quick summary, let’s explain what each speaker wire does.

CL2 Speaker Wire

In full, CL2 means “Class 2”. Their application is meant for low-voltage stuff.

CL2 speaker wires

Examples of low-voltage are simple fans, compressors, and conveyor belts.

The voltage limit for a CL2 speaker wire is 150 volts. Most homes have a voltage limit of 150, and there’s a reason for this.

The government doesn’t want people in residential homes dying due to electrocution mistakes.

Somebody who isn’t familiar with electricity are prone to electrical shocks and electrical hazards.

Aside from being able to withstand 150 volts, CL2 cables are also classified as “Riser Rated” (CL2R) and “Plenum Rated” (CL2P).

Riser Rated

Riser rated cable is used between floors.

Imagine if you have a 3 story house; in between those floors is space for the wire to run through, this is where riser rated cables come in.

If you have a multi-channel speaker set-up at your house, CL2 cables can help you connect multiple speakers on different floors.

It’s perfect for setting up indoor speakers all over your house.

One major downside to both CL2 and CL3 cable wires is their potential for being human carcinogens.

This means the material in the cables can cause humans cancer.

Riser rated cables are also found in general purpose areas.

Examples of this are office floors and storage rooms.

If you wanted speaker wires more versatile, then consider plenum cables.


To understand plenum cables, we need to first understand what plenum means.

Plenum spaces are spaces below a floor or above a ceiling that work as air ducts.

Plenum Cables

To elaborate, they’re spaces which have a lot of air circulation (good), but when there is a fire, the plenum space will make the fire bigger because fire grows from oxygen (bad), which a plenum space has a lot of.

The reason why plenum cables work in air ducts comes from being a flame retardant and special plastic.

This plastic doesn’t smoke as much which helps stop fires.

If we come back and look at the full picture on CL2 speaker wires, we know 2 elements make it up:

  1. Riser-rated
  2. Works well in plenum space

CL3 Speaker Wire

CL3 Speaker wires are the exact same EXCEPT they can handle 300 volts.

CL3 speaker wires

Final Words

Speaker wires are a big part for both outdoor speakers and indoor speakers because both need them.

If you’re going to install wires in your house, backyard, or patio, they need to go through a wall/floor.

Both CL2 and CL3 wires run through both.

The only difference between them is CL3 speaker wires can take 300 volts, compared to 150 volts of CL2 speaker wires.

Take this in mind when selecting your indoor/outdoor speakers.

You don’t want the amplifier of a speaker to be stronger than a CL2/CL3 speaker wire or else it will blow out.



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