Orbit FA-4S Deep 4" Square Wel...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$6.65
Orbit FA-4S Deep 4" Square Welded Fire Alarm Box with MKO

Orbit FA-4S Deep 4" Square Welded Fire Alarm Box with MKO

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Model: FA-4SDB-MKO

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

$6.65
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Orbit FA-4S Deep 4" Square Welded Fire Alarm Box with MKO

The Orbit FA-4S is a deep, 4" square fire alarm box built with fully welded construction and a machine-knockout (MKO) design, engineered to provide a rugged, secure enclosure for fire alarm system components in commercial and industrial electrical installations. This family is available in two deep-body depth options, 2-1/8" and 3-1/2", giving installers a choice of interior volume within the same compact 4" square footprint depending on the wiring, splice, and device-mounting room required for the job. Welded seams deliver a solid, one-piece enclosure that resists flexing and separation across both depth options, while the MKO feature allows for clean, controlled conduit entry points to be made in the field as needed for the specific installation layout.

Key Features

  • 4" Square Footprint: Sized to the standard 4" square format for compatibility with common fire alarm system layouts and mounting hardware.
  • Deep Body Profile, 2-1/8" or 3-1/2": Choose the depth that best fits the installation, with extra interior room for wiring, device mounting, and splice management versus a standard shallow box.
  • Welded Construction: Fully welded seams create a durable, one-piece enclosure that resists separation and adds structural rigidity for long-term reliability across both depth options.
  • MKO (Machine Knockout) Design: Knockout points are engineered for clean conduit entry, allowing installers to open only the entries required for the job.
  • Fire Alarm System Application: Purpose-built as a fire alarm box, suited for housing fire alarm devices, pull stations, or associated wiring within a code-driven electrical layout.
  • Consistent Family Design: Both the 2-1/8" and 3-1/2" deep versions share the same 4" square welded body and MKO conduit-entry design, so installers can standardize on the FA-4S family and select depth per application.

Technical Specifications

  • Size: 4" Square
  • Depth Options: 2-1/8" and 3-1/2"
  • Construction: Welded
  • Knockout Type: MKO (Machine Knockout)

Typical Applications

  • Fire Alarm System Installations
  • Commercial and Industrial Electrical Enclosures
  • Conduit and Raceway Systems
  • New Construction and Retrofit Fire Alarm Wiring
  • Device and Pull Station Housing

Why Orbit?

Orbit's FA-4S family delivers the welded, deep-body construction and MKO conduit entry design that installers rely on for dependable fire alarm box performance, whether the job calls for the 2-1/8" or 3-1/2" depth option. The one-piece welded body and generous interior depth across both sizes make this family a practical choice for professional electrical work where durability, flexibility in interior volume, and clean conduit routing matter.

Manufacturer Resources

Product Specs

list_batch:
ORB-20260924
Product Type:
Outlet Box
Configuration:
Welded MKO Knockout
Department:
Electrical
Product Subgroup:
Electrical Boxes
Product Group:
Boxes & Enclosures

Orbit FA-4SDB-MKO – Frequently Asked Questions

1) What depths does the Orbit FA-4S 4 inch square fire alarm box come in?
Two deep-body depths within the same 4 inch square footprint: 2-1/8 inch (part FA-4SDB-MKO) and 3-1/2 inch (part FA-4SEDB-CKO). Pick the 2-1/8 inch when you just need splice and conduit room behind a device, and the 3-1/2 inch when a pull station body, end-of-line resistor, or a heavy bundle of circuit conductors has to live inside the box.
2) Will a standard 4 inch square cover or device ring fit the Orbit FA-4S?
The FA-4S uses the standard 4 inch square format, so it works with common 4 inch square mounting hardware and fire alarm layouts. Depth does not change the opening, both the 2-1/8 inch and 3-1/2 inch bodies share the same 4 inch square face and welded body design.
3) What does MKO mean on the Orbit FA-4S fire alarm box?
MKO is machine knockout. The conduit entry points are pre-formed into the welded body so the installer opens only the entries the layout actually needs and leaves the rest closed. That keeps the enclosure sealed where you do not want penetrations, which matters on a fire alarm circuit run.
4) Is the Orbit FA-4S a one-piece box or is it riveted together?
Fully welded. The seams are welded rather than crimped or riveted, giving a one-piece body that resists flexing and separation when conduit is torqued into the knockouts or the box is pulled during rough-in. Same construction on both the 2-1/8 inch and 3-1/2 inch versions.
5) Can I use the FA-4S box for a manual pull station?
Yes, housing fire alarm devices, pull stations, and associated wiring is exactly what the FA-4S is built for. If the pull station body projects into the box, go with the 3-1/2 inch deep version so the device and the circuit conductors are not fighting for the same space.
6) Can I standardize on one fire alarm box across a whole building and just change depth per location?
That is how the FA-4S family is set up. Both depths use the same 4 inch square welded body and the same MKO conduit entry pattern, so a facility or MRO buyer can spec one box family and order the 2-1/8 inch for shallow device locations and the 3-1/2 inch where junction and splice volume is needed, without changing covers or mounting approach.
7) Is the FA-4S suitable for retrofit fire alarm wiring, or only new construction?
Both. Orbit lists the FA-4S for new construction and retrofit fire alarm wiring, as well as general commercial and industrial enclosure and conduit or raceway work. On a retrofit, the machine knockouts let you open only the entries that match the existing conduit runs.
How fast can I get the Orbit FA-4SDB-MKO 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 Orbit FA-4SDB-MKO come with a warranty?
Absolutely. The Orbit FA-4SDB-MKO 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 Orbit FA-4SDB-MKO?
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 Orbit FA-4SDB-MKO from ZenSupply?
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