OT - Pigtail Ground to Metal Box

Do I have to pigtail a ground to the metal boxes? I see that the outlet ground makes a metal to metal contact with the metal box.

If I should run a pigtail ground, what the heck size screw should I use on the box. This type of box does not come with a ground screw and I just don"t see a bag of "ground screws" at the big box store electric aisle.

Thanks in advance.

Home Depot carries the grounding screws, just look for a package of green hex-head self-tapping screws. Although you can use bare wire, I like to use green just to reduce the chance of a short in the box.

I also run a separate green ground wire between all of my boxes. That way I still have a good ground even if a conduit connecter comes loose.

Like you (if I understood your post as you intended) I liked the grounding pigtail screwed into the box serving as its own dedicated equipment ground plus, of course, the receptacles ground screw for its equipment ground terminal. The receptacle, if properly and well secured mounted into the box, is grounded by its own ground wire PLUS gets another bond in contact with the box metal, but even if its pulled out for service, the box remains gronded by that pigatil mentioned above

I figure thats a WIN WIN situation to comply with the code and stay as safe as possible.....

John T Longgggg retired sparky EE

YES those metallic handy boxes/switch n receptacle outlet boxes MUST BE GROUNDED/BONDED to the equipment grounding conductor.

The receptacle has its own grounding screw/terminal but the metallic box needs also to be grounded cuz what it the receptacle was loose or was not bonded to the box?????

Another method Ive seen used for grounding is the lil greenie wire twist nuts that are hollow open in the tip end so an extra long length of an equipment grounding conductor can pass through and then be attached elsewhere.

John T (Long retired and a tad code rusty EE)

Equipment grounding screws must be green and hex headed (250.126)

If these are surface mounted metal boxes, NEC 250.146(A) says that a bonding jumper is not needed from the receptacle to the box, so long as you remove at least one of the insulating washer/screw retainers on the yoke of the receptacle, and of course, attach a ground conductor wire to the ground screw on the receptacle.

Charles