QA/QC Questionnaires CONDUIT/CABLE TRAY/ENCLOSURES

 

CONDUIT

a. What is the minimum size of conduit for instrumentation and its support distance

b. A conduit outlet box shall be installed within 18 inches of the field device, and the cable to

the Instrument shall be looped one or more times within this fitting.

c. Flexible conduit shall be used at the instrument end of the conduit to provide isolation from

vibration and protection against thermal expansion of the rigid conduit.

d. Conduit above ground in severe corrosive environments shall be PVC coated min. thickness is

40 mils per NEMA RN 1.

e. Conduit fittings for outdoor rigid steel conduit and liquid tight flexible metal conduit shall be

cast or forged steel, cast iron or malleable iron, either hot‐dip galvanized or zinc electroplated

( no aluminum fittings or fittings accessories shall be used in outdoor installation )

f. Conduit and cable entries to field junction boxes shall be through the bottom. Top entries are

allowable and provide a drain seal installed on the conduit within 18 inches away from the

enclosure.

CABLE TRAY

a. The maximum spacing between expansions joints shall be based on a temperature differential

of 55 deg. C an expansion gap settings shall be in accordance with the recommendations of

NEMA VE 2 based on the temperature of 0 deg. C and a maximum temperature of 55 deg. C.

b. All fasteners used to connect and assemble the cable tray system shall be 316 SS.

c. Cable tray shall be grounded as required in SAES‐P‐111.

d. Cable tray fill shall comply with NEC Article 392.

ENCLOSURES

a. Enclosures’ for Instrument in outdoor plant areas shall be NEMA Type 4 in accordance with

NEMA ICS 6 and NEMA 250 or IEC 60529 Type IP 65.Enclousure in severe corrosive

environments shall be NEMA Type 4X or IEC 60529 Type IP 66.

b. The Junction Box in a class 1 Zone 2 location and d in Hazardous areas shall be a single door

NEMA Type 4X or IEC 60529 Type IP 66 box. The box construction shall meet the following

requirements.