SEPCO 539M Steel Conduit Penny...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$12.39
SEPCO 539M Steel Conduit Penny, 4-Inch Knockout Closure

SEPCO 539M Steel Conduit Penny, 4-Inch Knockout Closure

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Model: 539M

In Stock (leaves warehouse same day if ordered before 3pm ET)

$12.39
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SEPCO 539M Steel Conduit Penny, 4-Inch Knockout Closure

The SEPCO 539M Steel Conduit Penny is a 4-Inch steel disc engineered to close off and seal unused conduit knockout openings in electrical boxes, panels, cabinets, and other enclosures. Formed from solid steel, this conduit penny drops into a matching 4-Inch knockout and provides a flush, finished closure once a knockout will not be put into service. Electricians rely on conduit pennies like the SEPCO 539M to keep an installation neat, keep unused openings covered, and avoid leaving open holes in a box or enclosure wall after layout changes. It is a straightforward, purpose-built piece of hardware for finishing out electrical boxes and panels, and a small accessory worth keeping on hand on any electrical truck or in any panel shop for change orders, layout revisions, and box or enclosure modifications.

Key Features

  • Trade Size: Sized for a 4-Inch conduit knockout, matching standard 4-Inch knockout openings in boxes and enclosures.
  • Durable Steel Construction: Made from solid steel for a rigid, long-lasting closure that resists everyday job-site handling.
  • Knockout Sealing Function: Serves as a penny/plug that permanently closes an unused conduit knockout opening.
  • Flush, Finished Fit: Delivers a clean, finished appearance on the box or enclosure surface where a knockout is not being used.
  • Simple, Fast Installation: Seats directly into the knockout opening for quick closure without specialized tools.
  • Job-Ready Hardware: A practical accessory for electricians finishing out panels, boxes, and enclosures on commercial and industrial jobs.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Sealing Unused Conduit Knockouts
  • Electrical Box and Panel Finishing
  • Commercial and Industrial Electrical Installations
  • Panelboard and Enclosure Modifications
  • Renovation and New Construction Wiring
  • General Electrical Maintenance and Cleanup

Why SEPCO?

SEPCO builds practical electrical hardware like the 539M Conduit Penny from solid steel for dependable, long-lasting performance in the field. This straightforward steel closure gives electricians and contractors a durable way to finish out unused 4-Inch knockouts cleanly and securely, keeping boxes and enclosures neat and properly closed. Choose SEPCO for well-made, job-ready electrical accessories built to hold up to everyday installation work, from small closures like the 539M Conduit Penny to the rest of the SEPCO electrical product line.

Manufacturer Resources

SEPCO Product Catalog

Product Specs

list_batch:
SEP-20260911
Product Type:
Conduit Plug
Department:
Electrical
Product Group:
Conduit & Raceway
Product Subgroup:
Conduit Fittings
Product Material:
Steel
Product Size:
4-Inch

SEPCO 539M – Frequently Asked Questions

1) What size knockout does the SEPCO 539M conduit penny close?
The 539M is a 4-inch steel disc, made to drop into a matching 4-inch conduit knockout in a box, panel, cabinet, or enclosure. It will not close a smaller opening, so for 3-inch or 2-inch knockouts you need the penny in that trade size rather than this one.
2) Can I use a conduit penny to cover an open hole left after removing a 4-inch fitting from a panel?
That is exactly the use case. The 539M closes a 4-inch knockout that was opened but never put into service, or one left open after a fitting comes out during a panelboard or enclosure modification. It gives a flush, finished face on the box wall instead of an open hole. The opening has to be a standard 4-inch knockout; an irregular or cut hole will not seat the disc properly.
3) Is a conduit penny the right way to close an unused knockout, or should I use a knockout seal?
A penny like the SEPCO 539M is a flat steel disc that seats into the knockout for a permanent, flush closure once you know the opening will never be used. It is the quick finish-out choice after a layout change or change order. A snap-in or threaded knockout seal is the better pick when you want a mechanically retained closure you can remove later, or when the enclosure needs a rated seal.
4) What is the SEPCO 539M made of, and will it hold up in an industrial panel?
Solid steel. That gives a rigid closure that takes job-site handling and stays put in panelboards, cabinets, and enclosures on commercial and industrial work. Steel also means it matches the enclosure wall material on most metal boxes rather than leaving a plastic plug in the run of sheet steel.
5) Do I need any tools or extra hardware to install a 4-inch conduit penny?
No specialized tools. The 539M seats directly into the 4-inch knockout opening for a fast closure, and nothing else is supplied or required with it. Order it on its own as a finish-out item, the way electricians keep pennies on the truck for layout revisions.
6) What part number do I order for the SEPCO 4-inch steel conduit penny?
Order SEPCO 539M. That is the manufacturer part number for the 4-inch steel penny, and it is the only model on the item, so there is no finish or material option to specify.
How fast can I get the SEPCO 539M delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the SEPCO 539M come with a warranty?
Absolutely. The SEPCO 539M is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the SEPCO 539M?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the SEPCO 539M from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
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