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Model # 20511

Internet # 100133208

Store SKU # 839647

3/8 in. Non-Metallic (NM) Twin-Screw Cable Clamp Connectors (5-Pack)

This item has been discontinued.
The Home Depot no longer carries this specific product.

$1.61 /bag




Model # 20511

Internet # 100133208

Store SKU # 839647

Turn to the Halex 3/8 in. Twin Screw Non-Metallic Cable Clamp Connectors (5-Pack) to join non-metallic sheathed cable and flexible cord to steel outlet boxes or other metal enclosures. A reversible locknut cuts through protective coatings on boxes and enclosures to preserve grounding.

  • Connect non-metallic sheathed cable and flexible cord to steel outlet boxes or other metal enclosures
  • Body and locknut are die-cast of high-strength zinc alloy
  • Zinc-plated steel clamp and screws
  • Reversible locknut cuts through protective coatings on boxes and enclosures to assure ground continuity
  • Fits 1/2 in. knockout
  • For indoor use only
  • Screws compatible with Phillips, slotted and square screwdrivers
  • Resists corrosion
  • UL and CSA safety listings


Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Trade Size (in.) 
Application type 
Compatible conduit type 
Electrical Product Type 
Standard Fitting 
Fitting type 
Galvanized Steel 
Package Quantity 
Product Weight (lb.) 
0.2333 lb 
Warranty / Certifications
Certifications and Listings 
1-UL Listed,CSA Listed 
Manufacturer Warranty 


Rated 4.3 out of 5 by 3 reviewers.
Rated 5.0 out of 5.0 by Excellent, easier to retrofit later These are excellent clamps. I'm in the process of retrofitting a house that has old metal boxes and 2 piece clamp connectors. The advantage with these is that you can loosen the wire from within the box, while 2 piece clamps can only be removed from outside... That means I have to destroy the box, the wire, or open the wall to get the clamps out. If these clamps were in the box, I could have removed the ring, extracted the box and save both the wire and box. I strongly recommend these to anyone using metal boxes. I would note the they have contractor 100 packs in store sometimes, but I haven't seen them online. Big cost savings in bulk as you can imagine. Otherwise this 5-pack is a better deal than individual at least. November 26, 2013
Rated 3.0 out of 5.0 by My Bad, Trade Size, Who Knew? Yesterday I submitted a negative review about this product. Then it came to me after waking from a good sleep. THE DARN LABLING INDICATED "TRADE SIZE". I had found an old, but unused light fixture with 1/2" knockouts. These were 'real world' measurements, with 1/2" measuring 1/2" true. I've been doing electrical wiring for 60+ years, but not as an 'electrician'. I've always been on the smart side of the electrical world, . . ELECTRONICS and Communications. I didn't know that electricians had stupid secrets for craft protection. Sorry about the negative review. Ray November 9, 2014
Rated 5.0 out of 5.0 by Excellent Clamps! These work great, for new work and for retrofitting. Attach easily to junction boxes and screw on tight. they keep romex cable very tight and secure. I would recommend anyone needing to run romex into junction boxes. March 25, 2014
  • 2015-10-02T14:02:01.959-05:00
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