So every time I go to do something simple in the house like replace this outlet, I always find something new lol. This outlet pictured below is installed in a metal box. The white neutral wires and the black hot wires are wired just fine to the silver and gold screws on the outlet respectively. But the two bare ground wires are coupled together and then go out the hole in the back of the box and are wrapped around the aft end of the screw on the back of the box. It's the screw for the metal clamp that holds the cables in place that are coming into the box. Except in this case, this particular "clamp" isn't being used because the wires are coming in the other side of the box.
So my question is if this is ok to leave the outlet grounded this way? Or should I run a wire from the outlet's green/ground screw to the other ground wires, and then ground them to a "new" screw on the box (instead of the back of the box).
What should be done is the two ground wires should be brought back into the box. The spare clamp should be removed and the screw put back in. Add a piece of ground wire to the splice, wrap it around the screw and bring it out to the receptacle.
The do have green ground screws that will go in the screw hole instead of the clamp screw.
Those can be used but are not imperative.
In particular, wrapping the loose ends of wires around the aft end of a screw sticking through the box is not a good or sufficient connection (bonding).
OT: Also, just twisting the ground wire ends together is no longer good or sufficient; a wire nut or crimp ring is needed. A (wood) screw that relies on wood behind the box to screw into is not good or sufficient for connecting wires to the back of a metal box
In particular, wrapping the loose ends of wires around the aft end of a screw sticking through the box is not a good or sufficient connection (bonding).
OT: Also, just twisting the ground wire ends together is no longer good or sufficient; a wire nut or crimp ring is needed. A (wood) screw that relies on wood behind the box to screw into is not good or sufficient for connecting wires to the back of a metal box
Thanks. I've seen AC cable into a metal box on one end. Then someone spliced Romex and then bonded the ground of the Romex to the metal box. I'm guessing this isn't permitted.
My understanding is that AC cable doesn't have a dedicated ground wire and relies on a bonding strip and the armor as a ground path. If my understanding is correct, how does one add a branch circuit without directly connecting to the ground?
For metal spiral flexible armor cable and metal outlet boxes, the bonding strip required for grounding does not have to extend into outlet boxes let alone be wire nutted to other ground wires. When metal conduit including spiral armored cable is properly attached to metal outlet boxes and to properly grounded panel boxes the various outlet boxes are considered grounded and Romex cable continuing downstream from those boxes may have ground wires attached to the box (not just wrapped around an unnutted screw shank) as described higher up in this thread.
Yes, I didn't pay attention to the picture that shows the grounds just wrapped around that screw and not clamped down with a nut.
But thank you for answer a question that has been bugging me. I always verified the continuity between the ground on branch romex and the cable/box but thought it might be against the code because it was a continuous wire back to the panel
The first time I saw armored cable I was so confused. I thought everything was ungrounded and the ground on the receptacles were just attached to the metal outlet box for show.
The metal spiral armor does not count as a ground wire if there is no bonding strip or wire running the full length inside, outside of any paper lining.
Hmm. I can't find any ground wire (inside or outside) or bonding strips. All I see are 2 wires and a metal clamp that connects the AC to the metal box. There is continuity between the nearby subpanel and the receptacle box but is the impedence possibly too high if there is a fault?
This is pretty much what I see if I were to remove the AC from the box (without the clamp):
Check if bonding wire has been cut or broken. It is pretty thin bare wire. Your cable doesn't look old enough to not have bonding wire.
If it doesn't have bonding wire, you may not get a good ground connection and even if you do have good ground connection now, once some corrosion takes place, it will have high resistance in ground, which is not good.
Bad ground path can be worse than no ground path. If you have hot wire shorted to bad ground, breaker may not trip since you would get less than breaker's rated load and this will overheat the wire and cause fire.
Don’t want to nitpick or go off on a tangent, and maybe this was just done somehow for the picture, or maybe you are already aware of it, but that bottom neutral on the receptacle in the picture isn’t connected properly.
Please feel free to nitpick, it’s what helps me learn and keeps us safe 👍
I can see in the picture it looks like the wire isn’t wrapped around the screw properly, is that what you’re referring to? I think it’s just the angle of the picture because it is in fact wrapped around the screw. Let me know if you’re talking about something else.
Yep, it looked to me (and my eyes are not great –lol) that the wire is hardly wrapped at all around the screw. I believe they are supposed to be wrapped 3/4 around the screw – and that’s the way the top neutral looks to me.
But now looking more carefully at the picture I can see where it’s just an illusion and it fooled me.
I need to run 3 dedicated 20 amp circuits to a new sauna from the breaker panel. Is it OK to use one 3 gang outlet box or I have to use each separate outlet box for each circuit? Thank you in advance for your help.
Previous owner upgraded the main panel to 200A about 13 years ago. It was permitted. From the main panel, there is a 50A double pole breaker that leads to a Federal Pacific Stab-Lok sub-panel in the garage about 100' away (pictures attached). There are about 10 circuits connected to this sub-panel such as a 1kW Microwave, Refrigerator, Dishwasher, Clothes washer, etc. All the heating and cooking is gas.
I believe the entire house was rewired 13 years ago when the main panel was upgraded. I haven't seen any cloth wiring, all outlets are properly grounded and every receptacle and switch in this ~1940s house has been updated. I believe this 100A sub-panel was the original main panel. I've confirmed that the unbonded neutral and ground separately return to the main panel and that the voltage between L1 and L2 is 240V. All the breakers are firmly attached and can be manually tripped.
However, I've recently learned the history of these ubiquitous panels (it seems like every house in my area that hasn't been remodeled has them). I've read [url=https://scotthomeinspection.com/federal-pacific-stab-lok-electrical-panels/]this article[/url] and some others and am convinced that I should upgrade it very soon. Although everything [i]appears[/i] fine and I've yet to trip a breaker, I believe that's the potential problem with the FPE panels and their bogus fault testing.
I'm comfortable installing receptacles and lighting fixtures, but I don't think this is a DIY project. I'd like to get an idea of how involved this upgrade will be. One main issue is: The existing sub-panel is 8"x10" and I haven't seen any 100A panels that small that can handle 10 breakers. If the new sub-panel is bigger, could re-connecting the wires be very difficult? I don't think there is any rigid conduit in the wall but I can't get a good look.
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I can easily provide more pictures if that will help.
I'd appreciate to hear your thoughts.
01-01-21, 06:25 PM
