I have a pre-existing #6-3 armored cable (without a separate ground conductor), as shown here:
I am replacing the range this was connected to, and would like to provide a 4-wire connection via a 14-50R by using the steel armor cladding as ground (as discussed in Can I use the metal cladding of a cable as ground for this range installation?).
For easy installation of the receptacle, I am hoping to use this product, which has a metal back with a 1 3/8" punchout. The receptacle product comes with a strain relief clamp, but I'm unsure whether it's appropriate for making a ground connection to armored cable. Is this clamp OK to use? If not, what is the right sort of clamp to use in this situation? I've included some photos of the clamp:
Best Answer
That is not the right clamp
The clamp/fitting you have is a two-screw type clamp designed solely for use with nonmetallic-sheathed cables (NM, UF, and perhaps SEU/SER). Instead, you need an armored-cable fitting that fits a ¾" KO and is of the right size to accept the outside diameter of your cable; there are several styles available, but the one you're most likely to find at a hardware or big-box store looks like the Arlington Industries 8402 depicted below: