EL question- neutral & ground connected
I noticed something (actually two things) in a box today that made me question the skill of the electrician who did this.
First, note that the copper grounding conductor to the screw on the switch has been cut. Was this done so that if an inspector looked at the ground screw he would see a ground wire attached, hoping that he wouldn’t notice it didn’t go to anything? Or am I jumping to conclusions in thinking that this was a shortcut?
Secondly, the matter that made me more concerned is the fact that the neutrals are connected to the grounds. I thought that the main panel was the ONLY place they are to be connected, even subpanels are supposed to have isolated grounds.
This box has three NM cables comin in. Two 14-2 and one 14-3. The 14-3 is using a white insulated conductor as a switch leg, that’s not confusing me (at least I don’t think so). But the neutrals from the two 14-2 cables are tied with a wirenut to all three ground conductors.
Am I correct that this is a big problem?
Replies
Man, that is soooo wrong...
I think the sparkie is on meth.
I have seen this many times, especially in old houses, in fact in my own house the neutrals and grounds ar in the same neutral bar in the panel. now the mess in that box doesn't speak well of the electrician that did it. As for the ground, what was it accomplishing attached to that screw in a non metallic box?
EGC, equipment grounding conductor. It is a system ground, it does not have to be grounded to a metal box. Its sole purpose is to redirect fault current away from the device. Any color wire can be used as a current carrying conductor (except green) as long as it is re-colored, or "phased". Most electricians use the appropriate colored electrical tape for this.
Yes, it is a code violation, see NEC 250. It has no equipment ground, and grounded conductors cannot be substituted with grounded conductors.
A main is bonded once at the first means of disconnect, at the service side, this means that the neutrals and grounds can share a bar and a jumper must be installed between the neutral and ground bars, and the ground bars are to be bonded to the can.
Like a previous poster, I see a potential electrocution hazard as well. Luck will determine whether or not the breaker trips in time.
Here's a dumb question. You can have problems if you have 14 gauge wire on a 30 amp breaker, because you may overload the current capacity of the wire before the breaker trips to protect from failure. I would assume this applies to both "hot" and "neutral" conductors, right? What I mean by that is, if you were to use one 14 gauge neutral wire to complete the circuit for two 14 ga. hot wires (on different breakers), you're not going to trip the breaker since the neutrals all go to the neutral bus, but you still have a dangerous situation with the amount of current the one 14 ga. wire could potentially be asked to carry.Am I thinking correctly?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
You are right. Amps are amps, whether flowing in the neutral or 2 hot wires. You could exceed the safe current in the one neutral and not trip the shared current source breakers.
Yes and no. Yes on the 30A breaker/14 AWG wire question. #14 is rated for 15A (I think, I hardly ever install anything that small). Firstly, the size of wire you use is dictated by its overcurrent protection, not the other way around. A wire that is that overloaded burns off its insulation and a massive fault ensues. I've never seen one like that, but I could imagine that it would be horrible. The breaker wouldn't trip, and the current would have no where to go. Basically, it would happen like: explosion, fire, death.....not necessarily in that order.
For the second question, the answer is no. You would be sharing a neutral on two circuits which is perfectly acceptable as long as you don't do it on an arc fault circuit (neutral on an AFCI is monitered by the breaker), and you land both overcurrent devices (breakers) on different phases in the panel, and the wire is sized for the overcurrent device. The situation you are describing can and might eventually happen if you share phases (I think that this applies less to a single phase system and more so to a three phase system.....but it is still good practice to balance both systems). I think with shared phases you have more potential current for the neutral to carry, and a better chance to ruin the insulation.
It gets quite technical, and it has been explained to me several times, but trying to muddle through a detailed explination (I've tried at Breaktime before) wont help either one of us. Basically, let me get back to you on that, I'll try to remember to ask my journeyman tommorrow. Good question.
I could tell you where it is legal to have 14ga wire on a 40a breaker but it would start a flame war.
Think "motor".
Edited 12/8/2008 9:27 pm ET by gfretwell
To clarify, I'm strictly speaking about single phase 240v residential service.For the sake of discussion, let's say you have two receptacle circuits with 15a breakers on the same hot bus bar. If I plug two 1,800 watt irons in, one on each circuit, would the neutral not be carrying twice is rated current?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
"one on each circuit, would the neutral not be carrying twice is rated current?"
Yes I believe because it is an inappropriately wired situation. If different legs the ckts cancel out each other on the neutral. Same phase they are additive.
You are describing a multiwire circuit and to be a "correct" multiwire circuit they would need to be on different legs/phases/buss bars, etc. A common trip breaker is best (/recommended/required?) IIRC to make sure all stays safe and no power is resident on the shared neutral if breaker on one leg is off.
Not an electrician but believe this is/was correct last time I looked.
Supplied with more than a grain of salt (;-0For those who have fought for it Freedom has a flavor the protected will never know.
Yes, correct, affirmative.......
JimNever underestimate the value of a sharp pencil or good light.
"What I mean by that is, if you were to use one 14 gauge neutral wire to complete the circuit for two 14 ga. hot wires (on different breakers), you're not going to trip the breaker since the neutrals all go to the neutral bus, but you still have a dangerous situation with the amount of current the one 14 ga. wire could potentially be asked to carry."Three wire circuits are connected with one neutral and two hots but the hots are connected to breakers on opposite phases at the panel. Since they are 180° out of phase with one another, when one is at +120V the other is at -120V. When both hots are in use with equal loads, they cancel one another out and the neutral actually carries no current. When the two hots carry unequal loads, the neutral current is only the difference between the two hots.BruceT
You are quoting the book and a great explanation, but I have seen some really strange goings on in panels over the years, and in boxes as well. the proper way would have been to nut the neutrals together and the grounds together, but separate of each other. I have found places where ALL the wires in the boxes are black ( circuit wire in conduit ) guess no one ever heard of phasing tape, but it surely happens.
Yes, you are correct there are clearly code violations here. For one, as you mention, ground wires (EGC, bare copper in this case) are not suppose to carry current in normal conditions. They only carry current during a ground fault. The white wires and the grounds need to be separated. I notice you say there are three cables, but I only see two ground wires.
The black wire attached to the switch ground ????????? I can't imagine why in the world you would do this. If it truely is being used as a ground wire then it would have to be re-identified with green tape on both ends of the cable.
Neutrals and grounds get connected in the main panel, but not downsteam (as they are in your case).
"I notice you say there are three cables, but I only see two ground wires."
One of the copper grounds is connected to the other two with a crimped sleeve. See pic, you can sort make it out.View Image
"The black wire attached to the switch ground ?????????"
The picture angle is deceiving, see the edited pic below. The switch is wired correctly, other than the lack of a ground.View Image
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Regarding the ground/black wire on the switch. Thanks, I'll look closer next time.
Cell phone photos are not allowed on Breaktime!
Not a cell phone, it's blown up (resized).Below is the full res. photo, since you asked so nicely.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Thanks. I've seen some sparkies get pretty messy in the box but none that violated the rules. Lots of problems with too many switches controlling one or two lights in the ceiling, then to top it off, they thrown in the Lutron rockers just to make three way/four way circuit a real nightmare to figure out.Actually, sparkies on crack would explain a lot of questions.Thanks again for the clear photo! Edited 12/8/2008 11:05 pm by woodway
Edited 12/8/2008 11:06 pm by woodway
>> The black wire attached to the switch ground ????????? I can't imagine why in the world you would do this. <<
Look closer, the black is connected to the common terminal of a 3 way switch - not to the switch ground screw.
Switch ground screw has a small bare copper wire butt under it.
JimNever underestimate the value of a sharp pencil or good light.
That yellow wirenut pushed in to the left - why's a black and a white wire going into that?
"That yellow wirenut pushed in to the left - why's a black and a white wire going into that?"I don't *think* that's a problem (other than the fact that it was not identified as "hot" with tape or a sharpie).That's using all three conductors in a piece of 14-3 cable to get power to another box. The red and black are the two legs on a 3-way switch configuration, and the white is what I have heard called a "white-hot feed" (I'm not sure if that's right, but I've heard the term used).
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Edited 12/8/2008 8:25 pm ET by JonBlakemore
Neutrals + grounds nutted together?
Not zactly code but it worked when the hack ran out of wire nuts.
:-)
Jim
Good news is it's not a fire hazard.
Bad news is that's a connection that will kill you dead, if you touch the wrong thing.
I can't believe a 'real' electrician did that...
that looks like homeownermess to me.
I agree the homey who did this was confused about where the ground went in a plastic box so he hooked to the neutral. When I see a white and a black under a wirenut is says "switch leg" but in this mess I would want to verify that.
First I thought maybe the ground and neutral were both being used for 3 way switch legs...
I see the situation of the ground and neutrals tied together as a potential shock issue.
As far as breaker tripping goes, it should trip at least as well (and very slightly faster)when the nuetrals and ground are tied together then without the ground and neutrals tied together. This is so because the resistance back to the panel is less, think of it as higher fault current.
As previous posts said, no matter how you look at it, its a code violation.