Product Summary

Longze Electrical Box Extension Rings provide the perfect solution for extending junction boxes that are recessed too deep into walls or ceilings during renovation. Manufactured in Yongnian,

China, our extenders allow for a flush finish with new drywall, tile, or wood paneling without removing the existing box.

• ✔ Safety Certified: Fully UL Listed for electrical safety and code compliance.

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• ✔ Multi-Material Options: Choose between heavy-duty Pre-Galvanized Steel or fire-resistant PVC.

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• ✔ Universal Fit: Compatible with all standard 4" square and octagonal junction boxes.

• Standards: UL 514A (Steel), UL 514C (Non-Metallic), NEMA OS-1.

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• Box Compatibility: 4-Inch Square, 4-Inch Octagon, 2-Gang, and Round boxes.

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• Extension Depths: 1/2", 5/8", 3/4", 1", 1-1/4", 1-1/2", 2".

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• Material: Pre-Galvanized Steel (G60/G90) or High-Impact PVC.

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Material Performance & Fire Rating Standards

• Ensuring electrical enclosure integrity and fire safety compliance.

Material Type	Wall Thickness	Tahan Korosi	Fire Rating (UL)	Best Applications
Pre-Galvanized Steel	1.6 mm (16 Ga)	High (G90 Zinc)	Non-Combustible	Commercial & Industrial
High-Impact PVC	3.2 mm	Excellent (Chemical)	UL 94 V-0	Residential & Humid Areas
Stainless Steel 304	1.5 mm	Maximum	Non-Combustible	Food Grade / Marine

Extension Ring Dimensions & Knockout Configurations

• Precise sizing for a perfect flush-mount with common wall thicknesses.

Model Size	Depth (Inches)	Volume (cu. in.)	Knockout Sizes	Weight (oz)
4" Square	1/2"	7.5 cu. in.	(8) 1/2" & (4) 3/4"	5.2 oz
4" Square	1-1/2"	21.0 cu. in.	(12) 1/2" & (8) 3/4"	11.5 oz
4" Octagon	1-1/2"	15.5 cu. in.	(4) 1/2" Side KOs	8.8 oz
2-Gang Rect.	1"	12.0 cu. in.	(4) 1/2" & (2) 3/4"	7.0 oz

Installation Selection Guide for Different Wall Types 

• Matching the correct extender depth to your finished wall material.

Avoid Pitfalls:

• Sharp Edge Prevention: Many cheap steel rings have burrs that can damage wire insulation. Longze rings undergo a smooth-edge deburring process to ensure 100% wire safety during pulling.

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• Screw Hole Alignment: We use high-precision stamping dies to ensure mounting holes align perfectly with all major box brands (Raco, Steel City, Hubbell), preventing cross-threading.

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• Galvanization Integrity: For our steel rings, we use G90 pre-galvanized sheets to ensure no rusting at the cut edges, maintaining ground continuity for the life of the building.

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Perfect Fit Assembly:

• Flush Mount Perfection: Designed to bring the front edge of the box flush with the finished wall surface, satisfying NEC requirements for combustible wall materials.

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• Included Hardware: Every extension ring comes with high-quality, long-reach mounting screws to handle deep recess scenarios.

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Quality Control & Logistics:

• UL Listed Verification: 100% compliance with UL testing for structural strength and electrical grounding.

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• Sea-Worthy Packaging: Reinforced carton boxes with internal dividers to prevent denting, shipped on Fumigation-Free Pallets from our Yongnian hub.

• Q: Can I stack two extension rings if the wall is very deep? A: Yes, our steel rings are designed to be stackable, though we recommend a single deep ring for maximum structural integrity if available.

• Q: Are the PVC extenders suitable for outdoor use? A: Our PVC extenders are UL listed for indoor use; for outdoor "wet" locations, we recommend our gasketed cast-aluminum weather-proof extension rings.

• Email:eric@lzfastener.com  What'sApp:+86 15350500528 WeChat:+86 18830006928 or 15350500528