Wire harness conduit fitting

01

Match conduit size, enclosure thread and bore

WISKA's datasheet for its EMBMFS-C-16-20 metal conduit fitting (nickel-plated brass, PA sealing gasket) pairs conduit nominal size NW 16 with an M20 × 1.5 connection thread of 9 mm screw-in length, a 15.5 mm inside diameter, 27 and 29 mm key widths and 33.5 mm overall length, for corrugated conduit. It specifies 5 N·m tightening torque for both the nozzle and the cap nut. [1]

Its EMBFS-48-63-BK fitting pairs NW 48 conduit with an M63 × 1.5 thread of 14 mm screw-in length and a 42.5 mm inside diameter. [2] Editorial note: the conduit nominal size and the enclosure thread are separate choices; check the fitting's bore against the harness, the thread against the enclosure hole, and the screw-in length against the wall and locknut.

Editorial calculation: a 15.5 mm bore has a cross-section of about 189 mm²; if you limit wires to 40% of it (an assumption, not a value from the datasheet), about 75 mm² of cable cross-section can pass. Check your harness against the bore of every fitting on the run. [1]

Give the supplier the conduit type and nominal size, enclosure thread and wall thickness, fitting shape (straight, 90°, swivel), harness diameter, IP rating, temperature range, material, fire and railway or UL requirements, quantity, and tightening instructions.

02

Choose sealing, material and approvals for the environment

WISKA rates the nickel-plated brass EMBMFS-C fitting IP67 for −45 to +145 °C, for railway technology. [1] Its EMBFS-48-63-BK has a UL94-V0 polyamide body, nickel-plated brass connection thread and TPU sealing gasket, is rated IP68 and IP66 for −40 to +100 °C, is listed for EN 45545 railway use, and carries UL 1696 approval only in conjunction with UL-approved corrugated conduits. [2]

Editorial note: the two datasheets show the trade-off: the all-metal fitting has the wider temperature range, the plastic-bodied one the higher IP rating. An IP or UL rating applies to the tested fitting-and-conduit combination, so order fittings and conduit from one system or ask for test evidence of the pair. [1] [2]

For metal conduit, connectors are made in other styles: one supplier lists electro-galvanised steel raintight compression connectors for EMT in 1/2 to 4 inch sizes. [3]

03

Read the sealing test behind an IP68 claim

HUMMEL's product page for its SNAPCLIC Duo-PA M20 fitting (article 1542201250), a polyamide part that works as both a cable gland and a conduit fitting for HUMMEL polyamide hose 1510110114, lists an NBR seal and protection classes of IP54 as supplied, IP68 with an additional O-ring tested at 10 bar for 30 minutes, and IP69K. It is rated for −40 to +100 °C and has an M20 metric external thread of 10 mm length, a cable clamping range of 6–12 mm, an outside diameter of 25 mm, a height of 44 mm and a 24 mm wrench size, in black RAL 9005, and it can be taken apart without tools. [4]

Editorial calculation: 10 bar is 1.0 MPa, so the IP68 claim here rests on a stated test pressure and time, while the IP rating without the O-ring is IP54; a quotation that lists IP68 should name the test depth or pressure, duration and the parts fitted during the test. A 12 mm cable or harness bundle has a cross-section of about 113 mm², and the 10 mm thread length compares with the 9 mm screw-in length WISKA gives for its M20 metal fitting, so check wall thickness and locknut space for both. [4] [1]

04

EMT and rigid conduit connectors, PVC fittings and flexible-conduit connectors

Listings include steel compression connectors and couplings for EMT and rigid conduit, PVC conduit fittings, and connectors for flexible conduit alongside cable glands.

05

Body, connection thread, cap nut, sealing gasket, locknut and bore

The cap nut and gasket carry the sealing claim and the bore limits the harness: WISKA's NW16/M20 brass fitting closes at 5 N·m and leaves a 15.5 mm bore. [1]

06

Conduit size, enclosure thread, IP rating, material and temperature for a conduit fitting order

An IP rating belongs to the tested combination: HUMMEL's polyamide M20 fitting reaches IP68 at 10 bar for 30 minutes only with an extra O-ring and is IP54 without it. [4]

07

Send the conduit, enclosure and environment data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Conduit: [type; nominal size; maker]
Enclosure: [thread; wall thickness]
Fitting: [straight; 90°; swivel; bore]
Environment: [IP; temperature; oil; UV]
Approvals: [UL; railway; fire]
Supply: [quantity; locknuts; torque]

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