EFLEX Square Duct Aids Underground Cable Installation

# Energy # Sustainability

Throughout Japan, cables are being buried underground to help prevent disasters and to realize more attractive scenery. In the past, utility poles have primarily been removed (underground cable installation) along major roads, but with the upcoming 2020 Tokyo Olympic and Paralympic Games, the target has been expanded to sidewalks. Given the limited space under city sidewalks in which cables can be buried and the high construction costs, however, underground cable installation has stagnated.


Kawasaki Avenue after underground cable installation (Takahata, Hino City) (right)

Scenery and sidewalk clearance have been improved (Tokyo Metropolitan Government Bureau of Construction website)

Large-diameter EFLEX Square Duct is key to reducing costs

EFLEX Square Duct underground cable-protecting pipe
is available in five sizes

In June 2017, Furukawa Electric Co. Ltd. began selling “EFLEX Square Duct”as a new member of our “EFLEX”(note) series of underground cable-protecting pipes. In February 2018, we added two large-diameter sizes for a total of five sizes.


Excavation area is small. Flexibly conforms to curved sections

Conventional multiple pipe stacked conduit.
This type of conduit is assembled by using pipe pillow to
secure the round PVC pipes in place.

Various approaches for reducing costs have been investigated, but the most common approach today is the pipe conduit method, in which several pipes are buried underground and the cables laid by passing them through these pipes.


EFLEX Square Duct has a square cross-section.
EFLEX Square Duct does not require pipe pillow
and can be directly stacked.

Meanwhile, EFLEX Square Duct with its rectangular cross-section does not require pipe pillow and can be directly stacked. This allows the pipes to be laid in a more compact manner and reduces excavation and other construction costs.
Moreover, EFLEX Square Duct can be easily bent by hand, so there is no need for curved pipes. EFLEX Square Duct can also be directly stacked, so there is no need for pipe pillow, which enables compact pipe laying and reduces excavation and other construction costs.


Satoshi Kozawa of the Furukawa Electric AT & Functional Plastics Division, Functional Plastics Products Department, states the following about the advantages of EFLEX Square Duct.
“Roads with high traffic volumes limit the distance over which pipes can be laid in a single night, so in general short five meter long pipes are used in these cases. These shorter pipes require more joints, so the workability and reliability of jointing EFLEX Square Duct become extremely important. For example, after cutting EFLEX Square Duct, the joint is made using an AQUA-Square supplied as an accessory of this system. In this case, jointing only requires about 30 seconds, or roughly one-tenth the time required when using rubber seal and screws. EFLEX Square Duct jointing also does not require any tools, so our customers are very pleased.”

(note) EFLEX underground cable-protecting pipe

Underground cable-protecting pipes are used to protect buried cables. As the first underground cable-protecting pipe developed in Japan, Furukawa Electric’s EFLEX is a round plastic corrugated pipe which has the strength to withstand underground burial while being light, easy to bend, and easy to work with. Over the 50 years since EFLEX was first sold in 1967, EFLEX has been used broadly from small-scale electrical work to large-scale public works projects.

50 years of EFLEX thanks to your support.