Yates Engineering Services continues to review and assemble its knowledge base on Fiber to the Home deployments across the nation. One of the newer trends that we have been studying and deploying is the use of multi-duct. Multi-duct is simply when 2 or more small ducts are combined in a plastic over sheath. Two popular versions of multi-duct are a four micro-duct and a seven micro-duct. The micro duct itself comes in a number of sizes with a 10 mm to 13 mm inside diameter most frequently used. Both of these sizes can be placed with the same 2” bore or trench that places a single, traditional 1 ¼” duct. Dielectric micro-fiber is then used to populate one of the micro-ducts, leaving many spare paths. The four-way is a new choice for long haul or trunk backbones, and the seven-way is a good choice for placement in denser areas, where the extra micro-duct can be used for drop paths along the road.
When used in this way, fewer access points, or hand holes can be placed along the path. When assigned to a premise, the multi-duct can be intercepted at a convenient place along the duct, and a coupler used to connect a drop duct that goes back to the customers Network Interface location to the mainline duct. Then a micro drop is blown or rodded into the empty tube from the nearest access point, and no boring under driveways is required. There is also no need to trespass in any yard except the yard of the customer that is being connected to the network. The only inconvenience – that of having to dig up and intercept the multi-duct, is offset somewhat by the fact that the duct would likely need to be dug into a hand hole at depth in any case.
When making a financial comparison of multi-duct to a more traditional deployment of one or two 1 ¼ ducts with access points placed on every other lot line, or conduit placed to feed drops across the street though a road bore, the price of running multi duct on both sides of the road is actually at par or less than the traditional layout. Multi-duct is becoming a more popular selection and offers a good deal of flexibility in an area where boring future drops may not be an option. Feel free to call or email Yates Engineering Services to determine if multi duct is a great option for your fiber deployment!