Where is plenum required?

Plenum rated cable has a special insulation that has smoke and low flame characteristics. It is mandated to be installed in any “air handling” space. For instance, most large office buildings use the ceiling to return air to the AC unit.

When should I use plenum cable?

If you have a large wall or ceiling return air grate; remove and see if there the air is channeled through sheet metal ducting. If there is no sheet metal duct; just the open ceiling or wall space, then you are required by law to use Plenum Rated cable.

What is plenum rated conduit?

Plenum-rated cable gets its name from an HVAC term—plenum spaces. When no conduit is used, plenum cable is often required since the cable is considered to be freely installed. Plenum spaces allow fire and smoke to travel quickly.

Under what conditions should you use a plenum grade network cable?

Plenum cable is mandated to be installed in any “air handling” space. For example, most large office buildings use the ceiling to return air to the AC unit. This qualifies this ceiling as a plenum ceiling, and all the cables that go through that ceiling must be plenum rated.

Can plenum cable be used outside?

Plenum cable is rated for the “plenum spaces” in buildings, which are simply the parts of the building that facilitate air circulation in heating and air conditioning systems. This designation simply means that the cable has been engineered to be buried without any kind of outside protection.

What is the purpose of a plenum?

Plenum boxes are usually situated on either side of the fan or heat exchanger and have the important function of bringing in, distributing, and removing air. They are the air’s first stop after being heated or cooled and its last stop before going back into your AC, heat pump, or furnace.

What is the difference between plenum and PVC cable?

PVC (Polyvinyl Chloride) is what your standard Category 5e and Category 6 cable jacket is constructed of. Plenum cable is made of Teflon or FEP which gives off much less poisonous gas than PVC when it burns.

Is it OK to run Ethernet cable outside?

Ethernet cable can go outside. Exterior-grade ethernet cable which is weatherproof can safely be used outside without the need for a protective conduit. Other types of ethernet cable that are not exterior-grade may still have a UV protective jacket to protect it from exposure to sunlight.

Is plenum cable waterproof?

Standard plenum or riser rated cables can’t be used in these situations since water will have a catastrophic effect on both their electrical performance and physical properties. The typical solution has been to use outdoor cable in the conduit and then transition to the appropriately rated cable type once indoors.

What is the difference between a plenum and a duct?

A plenum is an air distribution box designed for forced-air systems on residential homes and commercial businesses. It is part of the ductwork, but far different than an air duct as these important boxes handle air as it enters the ducts and helps to recirculate it within a system.

What is plenum in duct?

A plenum is an air-distribution box attached directly to the supply outlet of the HVAC equipment that heats or cools the air to make the house comfortable. The ductwork that distributes the heated or cooled air to individual rooms of the house connects to the plenum.

Is plenum a PVC cable?

Do I need to use plenum rated conduit?

If you’re using plenum-rated conduit, you don’t need to use plenum-rated cable. This is true even if the conduit is in a plenum space. The most common types of plenum conduit are innerduct (often used for fiber runs) and metal. PVC pipes are generally not plenum-rated.

Can you use plenum cable in a non plenum space?

Most building codes mandate that only plenum-rated (CMP) cable be used in “plenum spaces” and air ducts. For large public spaces like hospitals, schools, and airports, building codes in some cities and towns mandate plenum cable even for non-plenum spaces.

Do I need a plenum cable in a false ceiling?

No a plenum cable is only required in a plenum the space above a false ceiling. In a conduit you can use almost anything. This is because a conduit stops most fires and prevents smoke from a burning cable from getting out.

Does your building inspector require plenum cable?

Q: As cabling contractors, we run into requests for proposals that require plenum or polyvinyl chloride (pvc)-jacketed cable. Most building inspectors are consistent in what they require, but fire inspectors seem to vary with their moods.