STI Series EP Power Shield Electrical Box Inserts

Protect Your Home or Business From Fires Started in Electrical Boxes

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What's special about this electrical box insert pad?

  • Intumescent insert designed to fit against the back wall and expand in a fire for safety
  • Can be used in electrical boxes, receptacles or switches to prevent the spread of fire or smoke
  • Adhesive strip on the back ensures proper bonding for a tight seal
  • Click for More Features

Protect your home or office from electrical fires with Power Shield electrical box inserts. Designed to attach to the back of the box and expand 24X upon exposure to high heat, they're perferct for maintaining the fire-resistance ratings of wall assemblies.


L x W x THICKNESS (inches)
STI-EP44 Electrical Box Insert Pad 3.75" x 3.75" x .125" 20 Red
STI-EP45 Electrical Box Insert Pad 4.25" x 4.25" x .125" 20 Red
  • Can easily be retrofitted for existing construction
  • Easy to install in the field, shop or office because no tools are required
  • Water resistant: will not disintegrate from moisture or condensation
  • Non-conductive: will not cause damage to your electrical wiring
  • UL263 (ASTM E119, NFPA 251)


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Weight EP-44 - 0.08 lb (0.036 kg)
EP-45 - 0.10 lb (0.045kg)
Volume EP-44 - 1.75 cu in (28.8 cu cm)
EP-45 - 2.50 cu in (41.0 cu cm)
Expansion Begin 350° F (177° C)
Expansion Range 350° F to >1000° (177° C - 537° C)
Volume Expansion 16 to 24X (free expansion)
In-Service Temp <130° F (54° C)
Oven Aging No Change (60° C)
Humidity Exposure No Change (60° C, 98% R.H.)
Shelf Life No Limit
STC Rating 65

This product has starred in our Product Showcase Blog! Click here to check it out.







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SSP PuttySTI SpecSeal® SSP Putty
An excellent product for retrofit jobs and cabling that call for a firestopping sealant. It is easy to apply and meets the highest quality standards. This 36 cubic inch bar is all you need for metallic conduits, telephone, data or electrical power cable penetrations as well as a variety of sleeved and non-sleeved applications.


Intumescent SealantSTI SpecSeal® Triple S® Intumescent Sealant Tube
This sealant is ideal for construction gaps and blank openings in walls or floors. Tested and approved for use with metallic penetrants up to 30", SSS can be safely combined with other SpecSeal products.

Firestop Sleeve KitsSTI Split Firestop Sleeve Kits
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