Legrand FD User Manual

GENERAL:

1. Review and become familiar with all flushduct components. Be careful of sharp edges or burrs when handling any sheet metal

parts. All interior surfaces that can be touched by a wire shall be smooth.

2. Compare and coordinate the architectural and electrical drawings with the Wiremold/ Legrand installation drawings. Contact
your local Wiremold field sales representative immediately if any dimensions or details are incorrect.

3. On arrival, check the shipment for shortages or damage. Contact your local Wiremold field sales representative immediately if
there are any problems. File a freight claim for any damage directly with the carrier. Keep material and cartons dry.

4. Install duct and related components in accordance with Article 354 of the latest issue of the National Electrical Code.

5. Wiremold/ Legrand recommends a vapor barrier be provided when duct is installed directly on grade. This barrier

prevents ground moisture from reaching the underside of the concrete slab through capillary action. This barrier would be
placed below any infloor distribution system.

Flushduct®Duct &
Junction Boxes

INSTALLATION INSTRUCTIONS

Installation Instruction No.: IBO169R1 – Updated May 2006

Wiremold/ Legrand electrical systems conform to and should be
properly grounded in compliance with requirements of the current
National Electrical Code or codes administered by local authorities.

All electrical products may present a possible shock or fire
hazard if improperly installed or used. Wiremold/ Legrand electrical
products may bear the mark as UL Listed and/or Classified and
should be installed in conformance with current local and/or the
National Electrical Code.

IMPORTANT: Please read all instructions

before beginning.

DUCT:

1. Flushduct is manufactured in three sizes:

a. Single – 3 1/8" [79mm] wide and 1 1/4" [32mm] deep.
b. Double – 2 single ducts welded side by side 6 1/4" [159mm] wide and 1 1/4" [32mm] deep.
c. Triple – 3 single ducts welded side by side 9 3/8" [238mm] wide and 1 1/4" [32mm] deep.

2. The largest conductor to be installed in either duct shall be 1/0.

Approx. Area Allowable Number of

Sq. In. Wires/Cables*

#2 Duct

Tele/Data Cables

2 pr. phone, Area = .0154 86
4 pr. phone, Area = .0380 35

Type 1 shielded twisted pr., Area = .1194 11
Coaxial, Area = .0460 29
25 pr. phone, Area = .1320 10

Power Conductors

#12 THHN, Area = .0133 100
#10 THHN, Area = .0211 63

# 8 THHN, Area = .0366 36
1/0 Cable, Area = .1855 7

WIRE FILL CAPACITY CHART

* Capacities based on 40% wire fill allowed by the National Electrical Code. At the 40% fill,

duct will be crowded and wire pulling may be difficult. When transiting through junction
boxes, around turns, and through inserts, wires will take up more space. A 20% wire fill at
these locations will allow easier fishing and pulling of cables.

3. Factory punched openings are threaded 1 5/8-18. For installation of screw plugs only. Only 455F Series can be installed in
this opening, or also in 1 5/8 straight through holes cut in the field..

2

FLUSHDUCT JUNCTION BOX:

1. Single Flushduct — Cat. No. 12FB

This box accommodates a single Flushduct on each side. The box has corner conduit openings.
Where the plans indicate a conduit feed coming into the corner of a junction box, use a box corner adapter Cat. No.
255-3/4, -1, -1 1/4, -1 1/2 to connect the conduit. Each junction box opening is to be connected to the duct so as to
form a continuous raceway for wire circuits.

2. Double Flushduct — Cat. No. 222FB

a. This junction box accommodates a double duct Flushduct raceway on each side. Partitions within the box isolate each

duct run and create a continuous raceway through the box in both directions. When a double Flushduct box is located
with the arrow pointing up, the two conduit corner entrances on the left can be used for home runs or for branch conduit
feeds from the left hand vertical duct run and/or the bottom horizontal duct run. Both conduit corner entrances on the
right side of the box can be used to feed the upper horizontal duct run and the right hand vertical duct run.

b. Where the plans indicate a conduit feed coming into the corner of a junction box, use a corner adapter Cat. No. 255-3/4,

-1, -1 1/4, -1 1/2 to connect the conduit.

c. Each junction box opening is to be connected to duct so as to form a continuous raceway for wire circuits.

NOTE: If a multiple duct junction box is given a quarter turn, the direction of the duct passages within the box is completely changed.

3. Triple Flushduct — Cat. No. 3222FB

a. This junction box accommodates a triple duct Flushduct raceway on each side. Partitions within the box isolate each

duct run and create a continuous raceway through the box in both directions.

b. The box corner entrances will feed the ducts in exactly the same manner as they do in a double Flushduct box. The

center duct cannot be fed from any of the box corners. They may be fed through the center duct openings in any side of
the junction box.

c. Where the plans indicate a conduit feed coming into the corner of a junction box, use a box corner adapter Cat. No. 255-

3/4-1, -1 1/4, -1 1/2 to connect the conduit.

d. Each junction box opening is to be connected to duct so as to form a continuous raceway for wire circuits.

NOTE: If a multiple duct junction box is given a quarter turn, the direction of the duct passages within the box is completely changed.

JUNCTION BOX & WALKERDUCT INSTALLATION:

1. Layout

a. Secure bench marks at convenient locations on walls or columns wherever the underfloor duct system is to be installed.

This will help establish the level of the finished concrete floor.

b. Obtain the location of the first duct run from the plans. Stretch a base line, at finished floor level, to correspond with the

center of the duct run. In the middle of and at right angles to this line, stretch another line. These two lines should be used
as measuring points for laying out the horizontal and vertical lines of duct.

c. If the project is a renovation and existing floors will be cut, the cut-out must be accurate. Cut-outs should be a minimum

of 2" [51mm] wider than the couplings/supports. Example: A triple duct system is 9 3/8" [238mm] wide and would require
a 13 3/4" [349mm] cut-out to clear the 11 3/4" [299mm] wide coupling support. Since concrete or grout must flow
beneath the duct system, the width of the cut-out may need to be increased. If couplings/supports are not being used,
the cut-out should be a minimum of 4" [102mm] wider than the duct system. The bottom of the duct system must rest
on a solid surface.

2. Locate Junction Boxes

a. Junction boxes are used at the intersections of duct runs.
b. Locate along the horizontal base line the points where junction boxes are to be centered.
c. Junction boxes must be positioned correctly so that the duct arrangement will conform to electrical drawings. After the

correct position is established and power and telephone service have been assigned to specific duct runs, the arrow on
the junction box side must be noted. All junction boxes in any one interconnecting area must be placed with the
arrow pointing in the same direction. This establishes a consistent pattern for all interconnecting duct runs. When
Wiremold/ Legrand layout drawings are provided, the arrows on the installed box must match the drawings.

d. Proceed with other rows of boxes, making sure that centers are lined up vertically and horizontally with the first row of

boxes. See chart below for dimension to allow or duct length between boxes.