Views: 0 Author: Site Editor Publish Time: 2026-10-12 Origin: Site
Conduit selection — the right size, material, and type for the job — is only the starting point. How it's bent, connected, and grounded in the field determines whether the finished installation actually protects the cables inside it and meets code. A conduit run with an over-tight bend radius, a loosely made connection, or a missing bonding path can undermine an otherwise correctly specified system. This guide covers the installation fundamentals that keep a conduit run performing the way it was designed to.
Every conduit type has a minimum bend radius, and bending tighter than that radius can kink the conduit wall, reduce its internal diameter at the bend, and make it difficult or impossible to pull cable through afterward. The correct bend radius depends on both the conduit's own wall thickness and type (thin-wall types like EMT/JDG bend differently than thick-wall threaded types like RMC/SC) and the cable fill requirements for that section.
Use a bender sized specifically for the conduit diameter being installed, rather than approximating with a larger or smaller tool
Avoid stacking multiple bends too close together on a single run, since this compounds fill reduction and makes cable pulling significantly harder
Check for kinking or flattening at the bend immediately after bending, before the run is fixed in place and harder to correct
Plan bend locations during layout rather than improvising them on site, so bend radius and fill requirements can be confirmed in advance
Conduit connection methods aren't interchangeable between types — threaded systems (like SC or RMC) need the correct thread engagement to maintain both mechanical strength and grounding continuity, while non-threaded systems (like JDG or EMT) rely on set-screw or compression fittings that need to be fully seated and tightened to spec. Mixing connection methods between incompatible conduit types is one of the most common field errors.
Confirm thread standard compatibility before connecting threaded conduit to fittings or enclosures sourced from a different standard (for example, Chinese GB/T thread vs. NPT) — outer diameters can coincidentally match even when threads don't
Fully seat and tighten set-screw or compression fittings on non-threaded conduit — an under-tightened connection is a common source of both mechanical looseness and broken grounding continuity
Avoid mixing conduit types within a single connected run unless using a fitting specifically designed for that transition
Conduit needs to be supported at intervals that prevent sagging and keep connections from bearing unintended mechanical stress — an unsupported or under-supported run puts continuous strain on every fitting along its length, which can loosen connections over time even if they were correctly tightened at installation.
Support conduit at the intervals specified for its type and size, rather than spacing supports by convenience
Add support near every fitting, box, or direction change, since these points concentrate mechanical stress more than a straight run does
Avoid letting conduit rest on cable tray, piping, or other services not intended to bear its weight
Metallic conduit systems typically function as part of the grounding path in addition to physically protecting the cables inside, which makes connection quality a safety issue as much as a mechanical one. A loose set-screw fitting or an under-torqued threaded joint can break grounding continuity even when the conduit still looks physically intact.
Don't assume mechanical connection automatically means electrical continuity — verify grounding continuity after installation, particularly on longer runs with multiple fittings in series
Use bonding jumpers at transitions to non-metallic conduit sections or to equipment enclosures, since continuity through the conduit itself ends at that transition point
Re-check connections for looseness during final inspection, since vibration or thermal cycling during and after installation can loosen a fitting that was correctly made initially
Bending tighter than the conduit's minimum bend radius, which can kink the wall and make cable pulling difficult or impossible afterward.
Connecting threaded conduit to a fitting from a different thread standard based on matching outer diameter alone, without confirming thread compatibility.
Under-tightening set-screw or compression fittings on non-threaded conduit types, compromising both mechanical strength and grounding continuity.
Spacing supports by convenience rather than specification, leaving fittings to bear mechanical stress they weren't designed for.
Assuming grounding continuity without testing it, especially across runs with several connections in series.
Choosing the right conduit type and size is the first step — the installation itself is what determines whether that specification actually protects the cables inside and maintains code-required grounding continuity. Bending within the conduit's rated radius, matching connection methods correctly between compatible systems, supporting runs at proper intervals, and verifying grounding continuity rather than assuming it are the installation practices that keep a conduit system performing as designed over its service life.
No. While JDG and EMT are functionally similar — both thin-wall, set-screw-type conduit — their fitting dimensions aren't interchangeable between the two standards. Using mismatched fittings can result in a connection that looks seated but doesn't achieve full mechanical or electrical continuity.
Visually check for kinking, flattening, or wrinkling of the conduit wall at the bend immediately after bending — any of these reduces the internal diameter and can make cable pulling difficult. If a test pull through the bent section meets unusual resistance, the bend radius is likely tighter than the cable fill requirements allow.
Not necessarily. A fitting can appear mechanically secure while still providing poor electrical continuity, particularly with coated or painted surfaces that interfere with metal-to-metal contact. Testing continuity directly after installation is the only reliable way to confirm the grounding path, rather than relying on visual or mechanical inspection alone.
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