Sealing Devices · Size 4 inch (100 mm)
4" Conduit Plug (100 mm)
A 4" conduit plug is a snap-in LDPE seal for open 4" (100 mm) conduit and duct — the size that closes the large primary electrical conduit and 4" duct on most underground jobs.
Innovative Plastics molds the 4" plug (part 2250-040) in low-density polyethylene with tapered, scalloped ridges that grip the inside of the duct for a secure snap-in seal, and a flanged lip at the base that gives crews a clean grip for tool-free removal.
Four-inch conduit is where a lot of water and debris can get in, so a reliable seal matters: the plug holds through the months a run may sit dormant, keeping silt, gravel, insects, rodents, and standing water out of empty raceway. The built-in rope-tie keeps a pull-line anchored for the eventual pull.
The 4" plug is one of twelve trade sizes from 1" to 8" on the temporary plugs page. Not sure which to order? The conduit plug sizing guide maps every size to a part number.
Specifications
4 inch (100 mm) sizes & part numbers
Price: $1.77 each, effective 2026-06-30. Minimum order one case; volume & distributor pricing available.
| Product image | Product Number | Trade Size (in) | Trade Size (mm) | Case Qty | Price (USD) | Order (cases) |
|---|---|---|---|---|---|---|
 | 2250-040 | 4.00 | 100 | 50 | $1.77 | |
Made in Texas, USA · ships across the US. Looking for other sizes? See the full Temporary Plugs range.
FAQ
Frequently asked questions
- What conduit does the 4" plug fit?
- Standard 4" (100 mm) conduit and duct. Order to the trade size of the duct you are sealing; for innerduct inside a host conduit, order the innerduct size.
- Can the 4" plug be reused?
- Often, yes. It installs and removes by hand without tools, so a plug in good condition can be pulled, set aside, and reused on the next job.
- Is the 4" plug suitable for outdoor and underground use?
- Yes. LDPE resists UV, ozone, and wide temperature swings, so the plug stays flexible and sealing on exposed risers and in buried duct alike.
Full product family
This page covers the 4 inch (100 mm) size. See every size, spec, and part number on the Temporary Plugs page or browse the full Sealing Devices range.
Guides & resources
- How to Size a Temporary Conduit Plug How to choose the right size temporary plug for conduit and innerduct — match the plug to the duct's trade size so it seals the opening before cable is pulled.
- Temporary vs. Permanent Conduit Plugs: Which Do You Need? The difference between a temporary conduit plug and a permanent duct seal — when a reusable snap-in plug is right, and when a job calls for a permanent sealing method instead.