Specifications - State of Delaware

SECTION 260533 - RACEWAYS: continued
below 10 feet-0 inch height, and for 480V feeder circuits to switchboards, and
panelboards.
2. Use steel zinc-coated EMT where routed higher than 10 feet above the floor in the hangar
aircraft bay, for interior 480V branch circuits, interior concealed 120V power, lighting,
alarms, controls, and communications in offices, corridors, toilets, break rooms, ceiling
plenum areas, and in the aircraft hangar bay above 10 feet-0 inch height.
3. Use flexible steel conduit only in movable partitions and from outlet boxes to interior
recessed lighting fixtures (Maximum of 6 feet long and a minimum of 4 feet long) in
nonenvironmental air plenums. Maximum length in environmental air plenums shall be
4 feet long), and final 24 inches of connection to motors, VFDs, transformers, and control
items. Provide where subject to movement and vibration where connections are in dry,
nonhazardous, interior locations. Provide in cells of precast concrete panels. Provide a
"green" insulated equipment ground wire suitably sized per NEC 250.122 unless
indicated otherwise in all flexible steel conduit. Except equipment ground wire is not
required on control circuits rated 20 amperes or less where flexible steel conduit 6 feet or
less in length is used only for vibration elimination purposes and not for purposes of
providing flexibility for movement.
4. Use liquid-tight flexible conduit in nonhazardous locations (length shall not exceed
6 feet, unless indicated otherwise) where subjected to movement and vibration where
connections are subjected to one or more of the following conditions:
a. Exterior location.
b. Moist or humid atmosphere where condensation can be expected to accumulate.
c. Corrosive atmosphere.
d. Subjected to water spray or dripping oil, water or grease.
e. Connected to a motor driving a nonsubmerged pump.
f. Provide a "green" insulated equipment ground wire suitably sized per NEC 250.122
unless indicated otherwise in all liquid-tight flexible conduit. (Except equipment
ground wire is not required on control circuits rated 20 amperes or less where
liquid-tight flexible conduit 6 feet or less in length and conduit is sized 1-1/4 inches
or less is used only for vibration elimination purposes and not for purposes of
providing flexibility for movement.)
5. Cut conduits straight, properly ream, and cut threads for threaded conduit deep and clean.
6. Field-bend conduit with benders designed for purpose so as not to distort nor vary
internal diameter.
7. Size conduits as indicated, unless no size is indicated then size per NEC, except no
conduit smaller than 3/4 inch shall be embedded in concrete or masonry.
8. Fasten indoor, dry location threaded conduit terminations in sheet metal enclosures by
2 locknuts, and terminate with bushing. Install locknuts inside and outside enclosure.
9. Conduits shall not cross pipe shafts, access openings or ductwork openings.
10. Keep conduits a minimum distance of 6 inches from parallel runs of flues, hot water
pipes or other sources of heat. Wherever possible, install horizontal raceway runs above
water and steam piping.
11. Support riser conduit at each floor level with clamp hangers.
12. Use of running threads at conduit joints and terminations is prohibited. Where required,
use 3-piece union or split coupling.
13. Complete installation of electrical raceways before starting installation of cables/wires
within raceways.
14. Use externally PVC coated galvanized rigid steel conduit for all below grade conduit that
is direct buried without concrete encasement.
260533-6 DEAN260533.DOC