Where Do I Install Riser and Plenum Cable?
Posted on August 28 2019
This is a reasonably common question that we get asked often, as both cables look physically identical. However, it is important to adhere to the fire codes and use the proper cable for your installation. Here is a simple breakdown of where to run riser and plenum cable.
Plenum Cable (CMP)
Plenum cable is used for plenum areas. Yes, that sounds simple doesn't it, but what is a plenum area? Plenum is a space that facilitates air flow for air conditioning and heating systems by providing a pathway for the air to flow in and out of. The most common spaces are between drop ceilings or under a raised floor. Now why would you need plenum cable for these areas? Plenum cable has a more fire resistant jacket than other cables. The jacket burns at a slower rate and most importantly releases less hazardous smoke. With plenum areas circulating air throughout the building, it's important to reduce hazardous smoke should the cables catch on fire. The reason for the substantial cost difference is the material cost. Plenum cable is made of Fluorinated Ethylene Propylene (FEP) material, which is nearly double the cost of riser cable material Polyolefin (PO).
Riser Cable (CMR)
Also referred to as PVC. Riser cable is most commonly ran through walls and any other non plenum areas. Plenum cable can always replace riser cable, but riser cable cannot replace plenum cable in plenum areas.