Originally Posted By: jpeck This post was automatically imported from our archived forum.
I thought Joe T.'s diagram on floating neutrals was very good and self explanatory.
Very aptly demonstrates what can happen when the service loses the neutral (or the neutral has a poor connection).
The service to my house lost its neutral and all kinds of things began happening. FPL (Florida Power & Light, our electric power utility) came out and said there was a bad neutral conductor underground. They immediately disconnect our service from the bad neutral and ran a neutral from our neighbors house to our house.
Then they put in it their schedule to replace the underground service lateral in two weeks.
I saw the neutral after it had been dug up. A rock in the back fill had been laying on the service lateral for 25 years, worn through the insulation, and the aluminum conductor had turned to aluminum oxide at that point. Once failure reached a certain point, strange things began to happen, and just got worse with time and rain (soaking the ground, really causing problems).
Accounts for the 160 volts I was reading on one phase leg and the 80 volts I was reading on the other phase leg.
Originally Posted By: Guest This post was automatically imported from our archived forum.
Joe,
I wasn't thinking that at all, and in fact, I inspected a house where all the neutrals were tied together in every box. It was a conduit set up and who ever wired it must have been thinking since the neutrals were all tied together at the panel, they must be OK to tie together everywhere.
The situation could create a potential shock hazard to a worker thinking the circuit that was being attended to...like a light at the end of a line was dead, when in fact the neutral wire could conceivably be carrying current.
I admit the chance of a fault occurring to cause this is remote, and it's unlikely that more than a tickle would be there, the possibility exists just the same.
Originally Posted By: Mike Parks This post was automatically imported from our archived forum.
Chad
"I will also surmise that there are very low odds of this happening."
If we are talking about the same thing, this was common practice here in Ohio because installers (under a licensed electrician) not electricians were performing the work.
Since I know that my above statement was not clear, let me give it again.
Two different circuits enter a box, the neutrals (grounded conductors) are all connected together. This is a code and safety violation and 'can' be a health hazard (you must understand EMF to argue this either way).
Originally Posted By: Guest This post was automatically imported from our archived forum.
Mike,
I agree w/ your statement, and that's why I said odds are it wouldn't be a problem but certainly could be. The potential for a hazard exists, but the circumstances that could create the hazard, while possible, are unlikely. It's not a desirable method just the same, and I called it as a defect in the home where I observed the condition.
Originally Posted By: dbozek This post was automatically imported from our archived forum.
I posted a rather comprehensive list of safety precautions on this message board some time ago regarding panel safety. It might be back a ways but for those interested, some good stuff there and a lot of interesting replies as well.
Originally Posted By: dbozek This post was automatically imported from our archived forum.
In the case of a “edison” circuit, there would be 2 different circuits with a common neutral for both circuits. In other words, the phase A leg (120volts) and phase B leg (120volts) coming into a junction box from a piece of 12-3 romex, would normally feed two different circuits but the neutrals for both of those circuits would be common to each other. A very common wiring practice. In two gfi protected circuits though, of different or the same phase, a separate neutral must be provided for each circuit.
If in fact the scenario that Mike presents are two circuits of the same phase, then tying the neutrals all together would not be the proper wiring technique. It is very possible to overload the single neutral conductor returning to the panel by doing such.
Originally Posted By: dbozek This post was automatically imported from our archived forum.
2 different phases or the same? I think there isn’t enough info in that post to make a solid determination. Nevertheless, each circuit is provided it’s own return except in the case of a edison circuit where one return could be used for both phases. Anything is possible in wiring depending on who is wiring it . The proper termination in this case though would be to tie the neutrals separately for each circuit.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Mike and Chad,
For one Mike you stated that there were four wires in the j box, not four cables. While one could logically assume you meant four cables because you connected the four black wires together in sets of two.
The second problem with this scenario is that you could not tell this j box had multiple feeds simply by looking at it. It would take some advanced diagnostic skills to locate the two feeds, like by tracing two of the cables back to the panel, or turning off one circuit which would still leave two of the four cables hot. That of course would require the use of something along the line of a voltage tester.
Now with that said, it is common to find four cables running into a j box, especially in an older home, or home with rewire work which are fed by one of those cables. In this installation the scenario you described would be a standard installation. I do however agree that neutrals for separate circuits should be kept separated but you should make your point more clearly as not to confuse every inspector on this board into calling four wires running into a j box as a defect. 
Originally Posted By: dbozek This post was automatically imported from our archived forum.
Good point Joe. Often, when rewiring a house, it is not practical to tie all the outlets together in a single branch circuit by opening up the walls to do such. Therefore, the wires for each individual outlet for that specific branch circuit are run to a junction box, either to the attic or basement, where they are all tied to the home run coming from the panel. Things to look for in junction boxes though are how many wires are being tied and what size wirenuts are being utilized. Generally 4 #12 gauge wires on a red wirenut is acceptable. Five under a red wirenut is pushing it. More than 5 should be under a blue or gray wirenut…ummm maybe I shouldn’t get into this depth but just giving some general info.
Originally Posted By: Guest This post was automatically imported from our archived forum.
Joe,
You're right. One can't assume that four cables running into a box are two circuits. Good point.
I'm still all revved up about the issue since I observed this at a home and I had it on my mind. Conduit installation, no covers on any j boxes in the basment. There was a perimeter loop around the basement so that the whole home could be fed. A good way to retrofit and an old home. What I saw was EVERY neutral tied together, in every box. I was looking at more than one circuit.
I'm again unsure of what Mike intended the question to be, but it was a good question in the regard that it had people coming at it from every direction.
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
Question:
Please supply an image or identify the actual information printed or engraved on the outer jacket of the cable you described.
In addition please see:
Quote:
334.17 Through or Parallel to Framing Members.
Types NM, NMC, or NMS cable shall be protected in accordance with 300.4 where installed through or parallel to framing members. Grommets used as required in 300.4(B)(1) shall remain in place and be listed for the purpose of cable protection.
Commentary: In accordance with 300.4(B)(1), where cable passes through factory- or field-punched holes in metal studs or similar members, it is required to be protected by listed bushings or listed grommets covering all metal edges and securely fastened in the opening before being installed.
See the commentary following 300.4(B)(1) for further information regarding physical protection of NM cables.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Chad,
While I do not doubt your wisdom, I just doubt that anyone could tell that the neutrals of several circuits were tied together just by looking at them.
The last time that I looked, neutrals should be tied together and I would expect to see them tied together everywhere I looked. It would take some advanced diagnostic skills and a large amount of time to determine you had the neutrals of several circuits tied together.
I would certainly be interested in seeing pictures of this also.
Originally Posted By: Guest This post was automatically imported from our archived forum.
Joe,
It's a good thing to tie all the neutrals from a single circuit together. When two circuits' neutrals are tied and an electrician is working on a circuit that he's shut off, there still remains (keyword coming up) the potential
for electrocution.
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
Quote:
In multiwire branch circuits, the continuity of a grounded conductor cannot depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.
Grounded conductors (neutrals) of multiwire branch circuits supplying receptacles, lampholders, or other such devices are not permitted to depend on terminal connections for continuity between devices.
For such installations (3- or 4-wire circuits), a splice is made and a jumper is connected to the terminal, unless the neutral is looped; that is, a receptacle or lampholder could be replaced without interrupting the continuity of energized downstream line-to-neutral loads .
Opening the neutral could cause unbalanced voltages, and a considerably higher voltage would be impressed on one part of a multiwire branch circuit, especially if the downstream line-to-neutral loads were appreciably unbalanced.
Quote:
This requirement does not apply to individual 2-wire circuits or other circuits that do not contain a grounded (neutral) conductor.
Originally Posted By: jfarsetta This post was automatically imported from our archived forum.
Joe,
Not busting balls here, so please dont take it this way.
How about a plain-language answer, instead of referring to a section of the electrical code? We are not code inspectors. We do not reference code when examining j-bozes, for the most part.
Help us out here...
Right or wrong, in your opinion... and, of course WHY.
-- Joe Farsetta
Illigitimi Non Carborundum
"Dont let the bastards grind you down..."
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Quote:
po?ten?tial ( P ) Pronunciation Key (p-tnshl)
adj.
Capable of being but not yet in existence; latent: a potential problem.
Having possibility, capability, or power.
Grammar. Of, relating to, or being a verbal construction with auxiliaries such as may or can; for example, it may snow.
n.
The inherent ability or capacity for growth, development, or coming into being.
Something possessing the capacity for growth or development.
Grammar. A potential verb form.
Physics. The work required to move a unit of positive charge, a magnetic pole, or an amount of mass from a reference point to a designated point in a static electric, magnetic, or gravitational field; potential energy.
See potential difference.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
BTW…the severity of the shock would be more dependent on the current being drawn at the time it was touched. When there is no load on the circuit(s) I would not doubt it would be nothing more than a slight tingle. Place a full load on it and you are going to get whacked.
Originally Posted By: Guest This post was automatically imported from our archived forum.
I’m not an electrician Joe, but yes I have more than a little installation experience and enough theory to make decisions about what not to touch.
Potential isn’t a big word and if we agree that the situation 's a problem, then our points were made. What I don’t understand is why you were playing dumb, I don’t get it.
The circuits I looked at were in the supply loop around the perimeter of the basement... there were 12 hots that I could observe enter the conduit from the panel. There were six neutrals, I could actually see the wires, it took no special equipment. By the time the wiring made it to the 4th j box, the four neutrals that were left were all nutted together. None of the j box covers were there, so it was a visual observation. I'll look for the photos tonight or tomorrow night.
Originally Posted By: Guest This post was automatically imported from our archived forum.
jmyers wrote:
BTW....the severity of the shock would be more dependent on the current being drawn at the time it was touched. When there is no load on the circuit(s) I would not doubt it would be nothing more than a slight tingle. Place a full load on it and you are going to get whacked.
Joe Myers
We agree again here, assuming all the neutrals lost their path. What I'd envisioned was a pigtailed neutral to a receptacle. Changing the receptacle likely wouldn't give much more than a tickle because the electrician wouldn't be as good a path as the ganged neutrals.
So that's twice in a day we agree. I don't know about you, but I'm feeling all warm n fuzzy.
. The proper termination in this case though would be to tie the neutrals separately for each circuit.