If you’ve spent any time shopping around for fiber optic cable you’ve probably seen some of them be labeled as OFNP, OFCR, or something of the sort. You’re probably wondering what these acronyms mean and whether or not they’re important to your project. Today I hope that we can clear up any confusion you might have about these different cable types and help you find the cable that’s right for you.
How to Define Fiber Cable Jacket Ratings
For starters, let’s break down the acronym to its most basic level and define each part so that we can look at any cable jacket and be able to tell what kind of application it can be used for. We’ve also included this helpful infographic.
Let’s start with the OF, which stands for optical fiber or optic fiber. This may seem pretty self explanatory but this part of the acronym simply lets us know that we’re dealing with a fiber cable and not a category cable or coax cable. Whenever the acronym begins with OF it will always be a fiber optic cable. The next part of the acronym is NC which stands for either Non-Conductive or Conductive. This lets us know whether the cable we’re working with is going to contain a conductive material. This might be helpful to know if your project requires your fiber cable to be in close proximity with materials that might give off some electromagnetic signal such as category cable. Finally, the GRP of the acronym stands for General-Purpose, Riser, or Plenum. Arguably the most important part of the acronym, this part lets us know what the cable’s jacket fire rating is. General-Purpose is the cheapest of the cable jacket lineup, but it’s also the least practical. This cable can catch fire and produce a ton of smoke if used in an area where fires can be common. The next cable rating is Riser, which is a bit more flame resistant than general-purpose but can still catch fire and produce smoke. The most flame resistant cable jacket by far is the Plenum rated cable. Plenum is the most versatile of the bunch and can resist flame and smoke for the longest.
So now that we’ve seen what each of the letters in the acronym mean, when we put them together, we can tell a lot about a cable just by reading it’s jacket. If it’s labeled as OFNR we know that it’s a non-conductive, riser-rated fiber optic cable. If the label says OFCP, we know that it’s a conductive, plenum-rated fiber cable.
Where to Use Fire Rated Cable Types
Now that we can properly identify which cable is which, we need to know where our cables can be used. We’ve also included another infographic to help clarify this for our visual learners.
Starting from the bottom, General-Purpose cable has the lowest fire rated jacket, and thus can’t be used in the same ways that riser or plenum rated cables can be. General-Purpose cable can still be used in areas that don’t have a strict fire code or areas where the cable can be visibly inspected. If you look at the graphic above, the general-purpose cable is in the same room as the workers and visible to ensure that it’s safe and protected from fire. The next cable application is Riser cable, which is mainly used in the walls of a building. Because riser jackets are more fire resistant, they can be tucked away and used in more areas than general-purpose. As stated in the previous section, Plenum is the most versatile because it has the highest resistance to flame and smoke. Because of this, plenum cable is used in the plenum areas of ceilings, air ducts, and areas where the risk of an unseen fire is more common.
Another important thing to note is that higher rated cable jackets can be used in lower rated settings but lower rated cable jackets can’t be used in higher rated areas. For example, plenum cable can be used for general-purpose cable application but general-purpose cannot be used for riser or plenum applications. For this reason, in most modern buildings installers will even use plenum rated cable for riser or general-purpose application.
Which Cable is Best for Me? Cable Jacket Scenarios
At this point you probably have a good idea about what each cable can be used for but maybe you’re still not sure what kind of cable you need for your project. Well the short answer is it depends. Don’t just think about what you’re going to be using the cable for, think about where you’re going to keep it. If you’re going to be using the cable for indoor application, what part of the building will it be in? Is it a high risk area for fire? Not only that, but maybe you might also have other types of cabling near the fiber. Consider the non-conductive varieties for those types of applications. In general, your safest bet for any job is always going to be plenum. Its high resistance to fire makes it the ideal candidate for any job. For a great selection of Plenum Rated Micro-Distribution or Plenum Rated Distribution Fiber, check out what we have in stock. What if you’re going to be using the cable outside? Well now we have a few things to consider. Nature has a way of messing up certain material by way of corrosion, animals, insects, etc. In that case you might want to go with an armored fiber which is usually a type of OFC. That was a test. Did you pass? OFC would be a conductive fiber cable. Our armored fiber cables are protected by an aluminum shell that hides under the jacket. Armored fiber cables are great for the outdoors or indoors where rats might try to chew through wires. This extra layer of protection will ensure that your fiber network will last a good few years. Top that off with a plenum rated jacket and now you have twice the protection from the elements. Check out our collection of Plenum Armored Fiber to see which cable is right for you.
If you're looking to start up your fiber network on a budget, you could always settle for the riser variety as it's a cheaper alternative and can still be used in a variety of different settings. If you're interested in those, check out our riser cable options in Distribution Fiber and Armored Fiber as well.
If you still have more questions about the practical application of any of these cable jacket ratings, here’s a helpful video.