STI Protective Cabinets – Type...
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$145.26
STI Protective Cabinets – Type 4X Polycarbonate Lockable Enclosures

STI Protective Cabinets – Type 4X Polycarbonate Lockable Enclosures

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Model: STI-7520

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

$145.26
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STI Protective Cabinets – Type 4X Polycarbonate Lockable Enclosures

STI Protective Cabinets are rugged, lockable enclosures designed to safeguard critical devices such as fire alarm panels, control equipment, and annunciators from damage, vandalism, and the environment. Constructed of UV-stabilized polycarbonate—the same tough material used in football helmets—these multipurpose cabinets offer a high level of visibility and durability. Available in a wide range of configurations, they include key or thumb lock options and models with siren or siren/strobe alarms. External mounting tabs and included hardware ensure easy wall installation. Many models are UL and Type 4X certified for industrial and commercial applications.

Key Features

  • Constructed from UV-stabilized polycarbonate (Type 4X rated)
  • Protects electronics from physical damage, dirt, and grime
  • Internal steel mounting plate included (most models)
  • Clear or white finish options depending on the model
  • Mounts externally to walls with included hardware and gasket
  • Alarm options: siren only, or siren with strobe
  • Available with key lock or thumb lock
  • Secondary eyelet for safety seal or padlock
  • UL/cUL S7255 Listed, UL38, UL50, UL2017 certified (select models)
  • Temperature range: -40°F to 250°F (-40°C to 121°C)
  • 3-year guarantee on polycarbonate, 1-year on electronic components

Model Height (in) Width (in) Depth (in)
STI-7520 19" 16.5" 6.44"
STI-7520OB 19" 16.5" 6.44"
STI-7520-OW 19" 16.5" 6.44"
STI-7521 19" 16.5" 6.44"
STI-7521OB 19" 16.5" 6.44
STI-7521-OW 19" 16.5" 6.44"
STI-7522 19" 16.5" 6.44"
STI-7523 19" 16.5" 6.44"
STI-7524 19" 16.5" 6.44"
STI-7525 19" 16.5" 6.44"
STI-7530 23" 19.46 8.875"
STI-7531 23" 19.46" 8.875"
STI-7532 23" 19.46" 8.875"
STI-7533 23" 19.46" 8.875"
STI-7534 23" 19.46" 8.875"
STI-7535 23" 19.46" 8.875"

 

Manufacturer Resources

VIEW SPEC SHEET

Product Specs

Product Line:
STI Protective Cabinets
Alarm Options:
None, Siren, or Siren + Strobe
Ingress Rating:
Type 4X (STI-7520 & STI-7530 Series)
Warranty:
3 Years (Polycarbonate), 1 Year (Electronic Components)
Accessories:
Mounting Hardware, Gasket, Optional Wire Shelf, Siren Replacement Kits
Back Box Option:
Frosted, Clear, Open, or White
Flame Rating:
94V-2
Lock Option:
Key Lock or Thumb Lock
Certifications:
UL/cUL S7255, UL38, UL50, UL2017 (select models)
Operating Temperature:
-40°F to 250°F (-40°C to 121°C)
Product Group:
Safety
Product Subgroup:
Cabinets & Enclosures
Product Type:
Protective Cabinets – Type 4X Polycarbonate Lockable Enclosures
Department:
Safety
Installation Options:
External Surface Mount (Includes Hardware and Gasket)
Product Material:
UV-Stabilized Polycarbonate with Steel Mounting Plate

Parts & Accessories

    Safety Technology International STI-7520 – Frequently Asked Questions

    1) Will an STI protective cabinet hold a fire alarm panel outdoors without water getting in?
    The STI-7520 and STI-7530 series carry a Type 4X ingress rating, which is the wash-down and corrosion-resistant class, so those two series are the ones to use where the enclosure sees weather, hose-down, or corrosive air. The cabinet mounts externally to the wall with the supplied hardware and a gasket that seals the housing to the surface. Operating range is -40F to 250F, so unheated garages, loading docks, and parking structures are all inside spec.
    2) What size fire alarm panel or annunciator fits inside an STI-7520 versus an STI-7530 cabinet?
    Two footprints cover the STI protective cabinet range. The 7520 series (STI-7520, 7520OB, 7520-OW, 7521, 7521OB, 7521-OW, 7522, 7523, 7524, 7525) measures 19 in high by 16.5 in wide by 6.44 in deep. The 7530 series (STI-7530 through STI-7535) is the larger box at 23 in high by 19.46 in wide by 8.875 in deep. Measure your panel's backbox and its conduit entries against those numbers, and remember the depth has to clear the panel door swing inside the cabinet.
    3) Key lock or thumb lock on a protective cabinet, which should I order?
    Both are offered across the STI protective cabinet range. A key lock keeps the box out of the hands of tenants and the public, which is what you want on a fire alarm panel or control equipment in a corridor or common area. A thumb lock opens with no key, so it suits back-of-house and maintenance-only rooms where the cabinet is there to keep dirt and knocks off the device rather than to keep people out. Either way there is a secondary eyelet on the cabinet for a safety seal or a padlock, so you can tamper-seal a thumb lock model or add a second layer to a keyed one.
    4) Do I need the siren version of the STI cabinet, or is a plain locking enclosure enough?
    Alarm is a per-model choice: none, siren, or siren plus strobe. Pick a plain enclosure when the problem is accidental damage, dust, or weather. Go to a siren model when the problem is people, since opening the cabinet sounds locally and turns a quiet tamper into an obvious one. Siren plus strobe adds the visual signal for noisy plant rooms, shops, and loading areas where a horn alone gets lost. On the STI protective cabinets, the alarm versions are offered with the frosted and clear back box only.
    5) What is the difference between the clear, frosted, white and open back box on an STI cabinet?
    The back box is the rear half of the enclosure and it decides what you can see and what you can mount to. Clear leaves the device fully visible, which is what inspectors want on an annunciator or a panel that has to be read without unlocking. Frosted softens the view while still passing indicator light. White is opaque, so it hides the equipment and blends into a finished wall. Open has no rear at all, which is the one to specify when the device is already surface mounted to the wall or has conduit entering from behind and you are adding the cabinet over the top of it. Clear, frosted, white and open are all available with either lock type.
    6) Is an STI protective cabinet UL listed for use over a fire alarm panel?
    UL/cUL S7255 Listed, with UL38, UL50 and UL2017 certification on select models. UL50 is the enclosure standard and UL38 covers manually actuated signaling boxes, which is what an inspector or an AHJ will look for on a cabinet going over life safety equipment. The certifications apply to select models in the range, so match the certification to the specific model number you are ordering rather than to the series as a whole.
    7) Will a polycarbonate cabinet crack or yellow if it is mounted where it gets sun or gets hit?
    The shell is UV-stabilized polycarbonate, the same material class used in football helmets, so it takes impact without shattering and the UV package is what keeps it from going brittle and yellow in a sunlit stairwell or an exterior wall. Flame rating is 94V-2. Most models include an internal steel mounting plate, so the device itself is bolted to steel rather than hanging on plastic.
    8) Can I standardize one STI cabinet across a whole property with mixed indoor and outdoor locations?
    Yes, and the way to do it is to pick the footprint first, then vary the options. Both cabinet sizes, 19 x 16.5 x 6.44 in and 23 x 19.46 x 8.875 in, run the same -40F to 250F range and the same Type 4X rated construction on the 7520 and 7530 series, so one model family covers a heated lobby, an unconditioned garage, and an exterior wall. Then spec lock type per location (key in public areas, thumb where only staff go) and alarm only where tamper is a real risk. That keeps one spare part list, one mounting detail, and one set of keys across the portfolio.
    9) How does an STI protective cabinet mount to a block or drywall wall?
    External mounting tabs on the outside of the housing take the fasteners, so you are not drilling through the sealed interior to hang it. Hardware and a gasket are included. Because the tabs sit outside the box, the enclosure seal is not broken by the mounting screws, which is what preserves the Type 4X rating on the 7520 and 7530 series. Plan your anchors for the substrate: the included hardware is what fixes into the tabs, and masonry or hollow-wall anchors are chosen to suit the wall.
    10) Can I tamper-seal an STI cabinet so I can tell if maintenance opened it between inspections?
    There is a secondary eyelet on the cabinet for a safety seal or a padlock, which is the usual way to run a break-away seal on life safety equipment so an inspection round can tell at a glance whether the box has been opened. Pair it with the thumb lock version where authorized staff need quick access without carrying a key, and the seal, not the lock, becomes your audit trail. Add a siren model where you want the opening announced at the time rather than discovered later.
    How fast can I get the Safety Technology International STI-7520 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 Safety Technology International STI-7520 come with a warranty?
    Absolutely. The Safety Technology International STI-7520 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 Safety Technology International STI-7520?
    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 Safety Technology International STI-7520 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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