NEUTRAL?? OR GROUND??
NEUTRAL?? OR GROUND??
I think I know the difference between neutral and ground in my house, but what is the difference in industrial applications when dealing with high voltage and three phase? How come some systems are grounded and some are not? The "ground" on an automobile is basically the return side of the electrical loop. (conventional theory). How does this compare to the ground in a high voltage, three phase AC system? Or would that be closer related to the neutral wire?
-
Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
Neutral and ground are the same.
In the floating system like a car when there is no actual ground path, a body, chassis, or wire path is used for that Neg.
In AC systems where there is the possibility of a ground acting as a negative or neutral, they use the actual ground/earth as that source.
So when its not possible, a return path called negative is used, when it is, the actual earth can be used as a primary or secondary source, or both.
In the floating system like a car when there is no actual ground path, a body, chassis, or wire path is used for that Neg.
In AC systems where there is the possibility of a ground acting as a negative or neutral, they use the actual ground/earth as that source.
So when its not possible, a return path called negative is used, when it is, the actual earth can be used as a primary or secondary source, or both.
-
Robert Reed
- Posts: 2277
- Joined: Wed Nov 24, 2004 1:01 am
- Location: ASHTABULA,OHIO
- Contact:
Neutral and ground are not the same.
The neutral wire if used is a common return path for conducted current only. The "ground" is a safety path for fault currents and to protect operators. There seems to be a common misconception that the earth is a conducting path for AC currents, probably due to the safety wire and neutral referred as "ground". No power company in the world uses earth ground as a conducting element. No electrical engineer in the world would even consider using earth for the same. The eath ground is used for one purpose only and that is to establish a reference. In this case we call it zero volts and is the reference to which all other voltages in the system, be they positive or negative are measured.Why earth reference? - probably because thats what everything is standing on and assumes that potential more or less. In three phase systems in which there is perfect balance,no current would flow through the neutral wire(also true for local240V systems). If imbalance is present, some current would flow here. In the real world there is always some imbalance so a neutral wire may or may not be included in the system depending on the design engineers choice. Generally in delta systems, there will be no ground. More commonly seen in star or'Y' systems.
The neutral wire if used is a common return path for conducted current only. The "ground" is a safety path for fault currents and to protect operators. There seems to be a common misconception that the earth is a conducting path for AC currents, probably due to the safety wire and neutral referred as "ground". No power company in the world uses earth ground as a conducting element. No electrical engineer in the world would even consider using earth for the same. The eath ground is used for one purpose only and that is to establish a reference. In this case we call it zero volts and is the reference to which all other voltages in the system, be they positive or negative are measured.Why earth reference? - probably because thats what everything is standing on and assumes that potential more or less. In three phase systems in which there is perfect balance,no current would flow through the neutral wire(also true for local240V systems). If imbalance is present, some current would flow here. In the real world there is always some imbalance so a neutral wire may or may not be included in the system depending on the design engineers choice. Generally in delta systems, there will be no ground. More commonly seen in star or'Y' systems.
In delta systems, there is no need for a neutral. However 3 phase wiring is normally supplied inside metal conduit, which is grounded for safety. I think Robert just made a typo in the above quote because everything else he said is correct. "Y" systems always have a neutral. If a "Y" system doesn't have a neutral, then it's a delta; not a "Y".Robert Reed wrote:Neutral and ground are not the same.
Generally in delta systems, there will be no ground. More commonly seen in star or'Y' systems.
It's like having an ape with a tail. If its got a tail, then it's a monkey, not an ape.
The ground in your house is not designed to conduct any current whatsoever. The neutral may carry current. The ground is only there for safety. But in your car, ground is a conductor.
Chris, however, continues to be wrong yet again about averything, over and over. Not even lucid, just rambles on and on....
Bob
-
Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
The fact that neutral and ground are the same doesn’t mean we use them as such.
The fact that often they are tried together says volumes.
Using them as a secondary ground is the only way to ensure its safety, however the earth does carry this current back like the neutral wire should.
It also stops stray grounding loops.
It also protects the user.
I use the ground wire all the time to ensure the safety of the neutral simply because there is no guarantee of it [neutral] operation as being perfect. Most often it is not.
To ground my work shop on a old house it was necessary to use the steel pipes in the house to the nutral wire and plugs on the wall simply because the neutral wire like most situations was completely ineffective and lost over 17 volts to ground way before it ever reached the power company’s dedicated neutral lead, or panel.
That or completely rewire the house, and most others?
The assumption that these wires are in good shape or that they all work properly will get you injured way before the regulation book assures you of your safety.
There are many myths surrounding the ground and neutral wires.... [Im sure we can hear them all here, from the lack of understanding]
According to the terminology in the CEC and NEC......
The word "neutral" is reserved for the white when you have a circuit with more than one "hot" wire.
Since the white wire is connected to neutral and the grounding conductor inside the panel, the proper term is "grounded conductor".
The fact that often they are tried together says volumes.
Using them as a secondary ground is the only way to ensure its safety, however the earth does carry this current back like the neutral wire should.
It also stops stray grounding loops.
It also protects the user.
I use the ground wire all the time to ensure the safety of the neutral simply because there is no guarantee of it [neutral] operation as being perfect. Most often it is not.
To ground my work shop on a old house it was necessary to use the steel pipes in the house to the nutral wire and plugs on the wall simply because the neutral wire like most situations was completely ineffective and lost over 17 volts to ground way before it ever reached the power company’s dedicated neutral lead, or panel.
That or completely rewire the house, and most others?
The assumption that these wires are in good shape or that they all work properly will get you injured way before the regulation book assures you of your safety.
There are many myths surrounding the ground and neutral wires.... [Im sure we can hear them all here, from the lack of understanding]
According to the terminology in the CEC and NEC......
The word "neutral" is reserved for the white when you have a circuit with more than one "hot" wire.
Since the white wire is connected to neutral and the grounding conductor inside the panel, the proper term is "grounded conductor".
-
dyarker
- Posts: 1918
- Joined: Fri Aug 22, 2003 1:01 am
- Location: Izmir, Turkiye; from Rochester, NY
- Contact:
True. However, since power is delivered to the panel as 2 phase (220) or 3 phase, there is more than one hot wire. From the panel to the load (outlet or light switch and light) is a branch, the white is still the neutral.The word "neutral" is reserved for the white when you have a circuit with more than one "hot" wire. ".
True. However, the proper term for the "green" wire (in some cable types "bare") is "non-current carrying grounded conductor".Since the white wire is connected to neutral and the grounding conductor inside the panel, the proper term is "grounded conductor".
Almost. But from the other things you've said you do use them as if they were the same.The fact that neutral and ground are the same doesn’t mean we use them as such.
False. It defeats the safety reasons for having a green wire. The earth does carry current, but don't. All the current is supposed to return on the neutral. The earth is very low resistance, but not zero; the ground rods at power company transformer and the one at your panel have resistance to earth. Dumping current into earth increases the voltage between those ground points, and more importantly, between those points and the location where the electricity is used; increasing the shock hazard. Using green to carry current can interfere with the operation of ground fault interupters. Causing the interupter not to trip while someone is being shocked, or more commonly false trips (depending on arrangement of white/green cross-connects).Using them as a secondary ground is the only way to ensure its safety, however the earth does carry this current back like the neutral wire should.
False. It causes ground loops.It also stops stray grounding loops.
Nonsense.It also protects the user.
I'm sure you do. You must be the luckiest SOB in the world not to have burned your house down or electrocuted yourself yet!I use the ground wire all the time to ensure the safety of the neutral simply because there is no guarantee of it [neutral] operation as being perfect. Most often it is not.
Possibly putting 17V (or more) on the faucets while drains, heating pipes/ducts and other conductive objects are at ground. You REALLY are a lucky SOB. At 17V it should have been repaired/replaced. Either there is a bad connection in the neutral run, or the current is too much for the wire gauge (in which case the black is still carrying too much current).To ground my work shop on a old house it was necessary to use the steel pipes in the house to the nutral wire and plugs on the wall simply because the neutral wire like most situations was completely ineffective and lost over 17 volts to ground way before it ever reached the power company’s dedicated neutral lead, or panel.
That or completely rewire the house, and most others?
True. However, your "cures" are the opposite of what should be done.The assumption that these wires are in good shape or that they all work properly will get you injured way before the regulation book assures you of your safety.
Yes, and you're the one spreading them. I haven't responded to your posts for months, but this is too dangerous to let it pass; so yes, you (the king of misunderstanding) are hearing from me and will hear from others.There are many myths surrounding the ground and neutral wires.... [Im sure we can hear them all here, from the lack of understanding]
Dale Y
-
Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
Sounds like a non working, no experience "load" to me.
Neither am I lucky, while the ground’s separate loop stops stray feed back, as mentioned.
To make a large single loop out of both can induce feed back or ringing.
The ground and neutral are separate to provide safety, however then why use the same point of ground as a reference, again still for safety.
Two is always better than one, while two negative wires are better than one even if they go to the same place, earth ground connection at the box.
The fact that they share the same ground at the box again says volumes, and the myths of the non working stiffs continues.
You can ground any point of receptacle to a dedicated ground pole, including the neutral contact and there is no fear of electrocution, period.
Neither am I lucky, while the ground’s separate loop stops stray feed back, as mentioned.
To make a large single loop out of both can induce feed back or ringing.
The ground and neutral are separate to provide safety, however then why use the same point of ground as a reference, again still for safety.
Two is always better than one, while two negative wires are better than one even if they go to the same place, earth ground connection at the box.
The fact that they share the same ground at the box again says volumes, and the myths of the non working stiffs continues.
You can ground any point of receptacle to a dedicated ground pole, including the neutral contact and there is no fear of electrocution, period.
I agree with the "let sleeping dogs lie" (interesting dual interpretations here) except in the case where life/safety is at risk.
NEC is pretty clear on this. Ground must carry less than a certain (low) limit of current - 5 mA sticks in my mind but I could be wrong on the specifics. Your GFCIs will pop like crazy if this is violated. Note that it's about the current not voltage.
I think neutral should have been named "return" to be more obvious. Though the current will really flow both ways.
as an aside, ground is a poor choice of terms in electronics as well when it really means 0 V as pointed out above. At least in one interpretation of the term. RF ground adds to the confusion (as well as the term "ground plane", heh heh). I've seen a good discussion of this somewhere but will leave it to others to find.
NEC is pretty clear on this. Ground must carry less than a certain (low) limit of current - 5 mA sticks in my mind but I could be wrong on the specifics. Your GFCIs will pop like crazy if this is violated. Note that it's about the current not voltage.
I think neutral should have been named "return" to be more obvious. Though the current will really flow both ways.
as an aside, ground is a poor choice of terms in electronics as well when it really means 0 V as pointed out above. At least in one interpretation of the term. RF ground adds to the confusion (as well as the term "ground plane", heh heh). I've seen a good discussion of this somewhere but will leave it to others to find.
Chris,
I have to concur with others on this subject. Using water pipes and such for neutral conduction is bad practice, a safety hazard and violates every electrical code internationally. It may have been your solution to avoid rewiring your hause but that just means your house needed the rewiring.
Having current running through your pipes and such will certainly cause galvanic corrosion which will make the problem worse instead of better. Eventually there will be a hot spot which could easily lead to a fire or arcing which could lead to an explosion. I don't know where you came up with these ideas but please speak to an electrician before too much longer.
I have to concur with others on this subject. Using water pipes and such for neutral conduction is bad practice, a safety hazard and violates every electrical code internationally. It may have been your solution to avoid rewiring your hause but that just means your house needed the rewiring.
Having current running through your pipes and such will certainly cause galvanic corrosion which will make the problem worse instead of better. Eventually there will be a hot spot which could easily lead to a fire or arcing which could lead to an explosion. I don't know where you came up with these ideas but please speak to an electrician before too much longer.
-
Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
Safety is the reason for splitting up and dedicating the two wires into two groups.
The use of GFI circuits, ground return problems, emergency back up, load bearing wires etc comes to mind.
Having two wires to do the same thing allows one as the back up.
In the old days only two wires were used, and again a ground was used for one of these.
There are many logical reasons for the split, however both can and do the same thing returning the power to a local ground, but separate and for safety reasons.
One wire is for carrying the return load to GROUND at the box, the other is a back up.
Sharing them on occasion doesn’t lessen the safety factors as electricity follows the path of least resistance.
Im not advocating simply placing all of your wires together as this negates some of its benefit from the safety precaution of having two back ups, two returns in a emergency, two means to assure your safety and ground loop faults.
However, returning electricity to Earth as close as possible follows the rule of electricity as it always finds its easiest path, and having to return all the way up the wiring to the box only to find the same ground pole or potential VS a short hop to another dedicated ground pole,.... in the ground nearby,... is also safe.
Unless your wiring is complex, a dedicated ground is always safe, safer than no ground at all or a ground neutral wire still going to the ground pole a long way away. No such thing as too many grounds unless it interferes with other goals.
As far as sleeping dogs, well they never learn any way because all they do is sleep on the job.
Argument and discussion is the only true way here for learning, ....fighting over it on the other hand is reserved for when you lose it.
The use of GFI circuits, ground return problems, emergency back up, load bearing wires etc comes to mind.
Having two wires to do the same thing allows one as the back up.
In the old days only two wires were used, and again a ground was used for one of these.
There are many logical reasons for the split, however both can and do the same thing returning the power to a local ground, but separate and for safety reasons.
One wire is for carrying the return load to GROUND at the box, the other is a back up.
Sharing them on occasion doesn’t lessen the safety factors as electricity follows the path of least resistance.
Im not advocating simply placing all of your wires together as this negates some of its benefit from the safety precaution of having two back ups, two returns in a emergency, two means to assure your safety and ground loop faults.
However, returning electricity to Earth as close as possible follows the rule of electricity as it always finds its easiest path, and having to return all the way up the wiring to the box only to find the same ground pole or potential VS a short hop to another dedicated ground pole,.... in the ground nearby,... is also safe.
Unless your wiring is complex, a dedicated ground is always safe, safer than no ground at all or a ground neutral wire still going to the ground pole a long way away. No such thing as too many grounds unless it interferes with other goals.
As far as sleeping dogs, well they never learn any way because all they do is sleep on the job.
Argument and discussion is the only true way here for learning, ....fighting over it on the other hand is reserved for when you lose it.
The proper name for ground in an AC house system is "Safety Return Ground" its main purpose (at the load end) is to provide an alternate return path to the neutral node should the equipment become damaged in such a way that a short occurs to the case.
It is normally connected to equipment with metallic chassis and is not required on equipment with plastic cases or double insulated construction. In plastic cased equipment, you need a polarized plug to prevent (any component case connected to neutral) from being biased to hot.
Bonding Neutral to safety ground at your breaker box accomplished the task above. Grounding that node to earth, provides protection from other faults that may occur including lightning (at your location and nearby in the transmission system)and wire faults downstream in the transmission system and open circuits or miswires in various locations within your house.
Grounding in an AC house system does not have anything to do with noise reduction though it may serve that purpose occasionally. When nothing goes wrong, the ground is redundant and unnessary, when something does go wrong, it could save your life
(Addendum in Edit): Running the safety ground in the same conduit or shieth as the neutral and hot is now required by NEC (older homes you will see 2 wire cable plus a seperate ground) One reason is apparenlly for EMI suppression. If current from the hot and return (wether that be neutral or ground) were to flow in two seperate paths, the electric and magnetic fields would not cancel and you would create a significant source or noise. The other reason has to do with maintianing the integrity of the grounding system and the NEC requirement for all splices to be located within accessible J boxes. In a seperately run ground (which I just ripped out of my kitchen) the conductor is often haphazardly connected using crimp splices anywhere convenient and almost never in a J box.
In conclusion, the safety ground conductor and interconnects should be thought of as a safety component rather than part of the interconnect wiring of your house.
It is normally connected to equipment with metallic chassis and is not required on equipment with plastic cases or double insulated construction. In plastic cased equipment, you need a polarized plug to prevent (any component case connected to neutral) from being biased to hot.
Bonding Neutral to safety ground at your breaker box accomplished the task above. Grounding that node to earth, provides protection from other faults that may occur including lightning (at your location and nearby in the transmission system)and wire faults downstream in the transmission system and open circuits or miswires in various locations within your house.
Grounding in an AC house system does not have anything to do with noise reduction though it may serve that purpose occasionally. When nothing goes wrong, the ground is redundant and unnessary, when something does go wrong, it could save your life
(Addendum in Edit): Running the safety ground in the same conduit or shieth as the neutral and hot is now required by NEC (older homes you will see 2 wire cable plus a seperate ground) One reason is apparenlly for EMI suppression. If current from the hot and return (wether that be neutral or ground) were to flow in two seperate paths, the electric and magnetic fields would not cancel and you would create a significant source or noise. The other reason has to do with maintianing the integrity of the grounding system and the NEC requirement for all splices to be located within accessible J boxes. In a seperately run ground (which I just ripped out of my kitchen) the conductor is often haphazardly connected using crimp splices anywhere convenient and almost never in a J box.
In conclusion, the safety ground conductor and interconnects should be thought of as a safety component rather than part of the interconnect wiring of your house.
Industrial plants often receive power as three phase power using three conductors. This will normally be at several thousand volts. Either a three phase transformer, or three single phase transformers will be used to convert this to a lower voltage. Since no return (neutral) is available, the primaries of these transformers will probably be delta connected.
The secondaries will probably be star connected. The center of the star will be grounded. This is done to minimize the voltage to ground of the power leads and to keep them balanced. Without a ground connection, the voltages on the secondaries with respect to ground would depend on load balance between the three phases.
Three phase loads (such as induction motors) can be connected without using a neutral connection if they are delta connected. If a neutral is used, then the load could also be star connected, with three hot leads and a neutral being connected back to the power transformers. With a three phase load, the neutral wire will only carry a current due to unbalance between the three phases.
If the phase to phase voltage is 208 volts, then the voltage from any phase to the neutral wire is about 120 volts. Single phase loads can be connected from one or more of the hot leads to the neutral wire. Differences in the loads connected to the three phases will result in current in the neutral wire.
The grounding wires are separate from the power distribution wires. Ordinarily, they do not conduct current. The purpose of the grounding system is to insure that all conductive material that can be contacted by a person is at the same potential.This includes the metal cases of equipment as well as plumbing pipes.
The electrical codes specify that the power distribution wiring and the grounding system shall be connected together at one, and only one, point. This is usually at the point where power is brought into the building. In the event of a failure in the insulation between the electrical system and the case of a piece of equipment, this will provide a current path with low impedance. If the grounds were separated, there would be some impedance between them, and a high current due to insulation failure might cause large voltage differences that would represent a safety hazard.
The secondaries will probably be star connected. The center of the star will be grounded. This is done to minimize the voltage to ground of the power leads and to keep them balanced. Without a ground connection, the voltages on the secondaries with respect to ground would depend on load balance between the three phases.
Three phase loads (such as induction motors) can be connected without using a neutral connection if they are delta connected. If a neutral is used, then the load could also be star connected, with three hot leads and a neutral being connected back to the power transformers. With a three phase load, the neutral wire will only carry a current due to unbalance between the three phases.
If the phase to phase voltage is 208 volts, then the voltage from any phase to the neutral wire is about 120 volts. Single phase loads can be connected from one or more of the hot leads to the neutral wire. Differences in the loads connected to the three phases will result in current in the neutral wire.
The grounding wires are separate from the power distribution wires. Ordinarily, they do not conduct current. The purpose of the grounding system is to insure that all conductive material that can be contacted by a person is at the same potential.This includes the metal cases of equipment as well as plumbing pipes.
The electrical codes specify that the power distribution wiring and the grounding system shall be connected together at one, and only one, point. This is usually at the point where power is brought into the building. In the event of a failure in the insulation between the electrical system and the case of a piece of equipment, this will provide a current path with low impedance. If the grounds were separated, there would be some impedance between them, and a high current due to insulation failure might cause large voltage differences that would represent a safety hazard.
-
Chris Smith
- Posts: 4325
- Joined: Tue Dec 04, 2001 1:01 am
- Location: Bieber Ca.
Bottom line, same as before. [applies to houses and dual 120 v inputs]
If your three wire system is working, leave it alone.
If your two wire system isn’t working, add in an dedicated ground as necessary.
If your three wire system is losing power and your not prepared to replace all the wires, then add in a second dedicated ground to neutral wire nearest to the fault.
One wire at the box to ground, or a second wire to absolute ground at the source of failure is well intentioned, and perfectly safe.
Keep in mind any GFI units,... as they need to sense these losses to fault properly. The better your grounds are tied into the neutral, the less the loss, thus they cant sense these failures.
If your three wire system is working, leave it alone.
If your two wire system isn’t working, add in an dedicated ground as necessary.
If your three wire system is losing power and your not prepared to replace all the wires, then add in a second dedicated ground to neutral wire nearest to the fault.
One wire at the box to ground, or a second wire to absolute ground at the source of failure is well intentioned, and perfectly safe.
Keep in mind any GFI units,... as they need to sense these losses to fault properly. The better your grounds are tied into the neutral, the less the loss, thus they cant sense these failures.
-
Dean Huster
- Posts: 1263
- Joined: Wed Dec 05, 2001 1:01 am
- Location: Harviell, MO (Poplar Bluff area)
- Contact:
The NEC is very confusing because it never refers to "ground" and "neutral" in wiring. It always calls them the "grounding conductor" and the "grounded conductor", respectively. I hate them for doing that because it IS so danged confusing with such closely-worded terms.
The ground wire is to never carry anything but fault currents while the neutral is the return current path for the hot wire in electrical systems. Even though it is not a current-carrying conductor, the NEC states that the ground wire is to always be of a gauge equal to that of the hot wire so that it can safely shunt fault currents to ground.
Delta systems can have a neutral, often used for 120V lighting circuits, and is developed using a center tap on a 240V three-phase secondary.
If a neutral is exhibiting a voltage with respect to ground, it does mean that there's an unhealthy IR drop somewhere on the neutral run, usually because of loose connection screws or bad splices somewhere. These should be sought out and repaired rather than being "worked around" using the ground.
The power company typically bonds ground to neutral at the transformer and again at the meter base. After that, they're always kept separate by Code. The telephone and cable companies like to use cold water pipes for their grounds, but these are signal grounds or lightning protection measures, not current-carrying circuits. The power company never uses plumbing for ground as they can't risk someone rerouting plumbing or swapping out a section of iron or copper with PVC. Yikes!!!
GFCIs will still operate properly even with poorly-operating neutrals, as the hot and neutral wires will still carry the same current on a non-fault load even with a high IR drop on the neutral. As a side note for some readers, a GFCI DOES NOT require a ground for proper operation and replacement of standard 2-wire outlets in bathrooms and kitchens with GFCI receptacles is a fantastic safety improvement. Non-grounded 3-wire GFCI receptacles and slave receptacles should have the included blue "NO EQUIPMENT GROUND" sticker applied to meet Code. Code otherwise forbids the use of non-grounded 3-wire receptacles.
Another "nasty" is the substitution of the required #10 or #8 wiring for heavy loads with parallel runs of #12. Should one of those parallel runs have a faulty connection or open up, you'd have a severely underwired circuit that could burn your house down. Our first house had the electric furnace wired that way because it was located in an area were Code and inspections were not required.
Dean
The ground wire is to never carry anything but fault currents while the neutral is the return current path for the hot wire in electrical systems. Even though it is not a current-carrying conductor, the NEC states that the ground wire is to always be of a gauge equal to that of the hot wire so that it can safely shunt fault currents to ground.
Delta systems can have a neutral, often used for 120V lighting circuits, and is developed using a center tap on a 240V three-phase secondary.
If a neutral is exhibiting a voltage with respect to ground, it does mean that there's an unhealthy IR drop somewhere on the neutral run, usually because of loose connection screws or bad splices somewhere. These should be sought out and repaired rather than being "worked around" using the ground.
The power company typically bonds ground to neutral at the transformer and again at the meter base. After that, they're always kept separate by Code. The telephone and cable companies like to use cold water pipes for their grounds, but these are signal grounds or lightning protection measures, not current-carrying circuits. The power company never uses plumbing for ground as they can't risk someone rerouting plumbing or swapping out a section of iron or copper with PVC. Yikes!!!
GFCIs will still operate properly even with poorly-operating neutrals, as the hot and neutral wires will still carry the same current on a non-fault load even with a high IR drop on the neutral. As a side note for some readers, a GFCI DOES NOT require a ground for proper operation and replacement of standard 2-wire outlets in bathrooms and kitchens with GFCI receptacles is a fantastic safety improvement. Non-grounded 3-wire GFCI receptacles and slave receptacles should have the included blue "NO EQUIPMENT GROUND" sticker applied to meet Code. Code otherwise forbids the use of non-grounded 3-wire receptacles.
Another "nasty" is the substitution of the required #10 or #8 wiring for heavy loads with parallel runs of #12. Should one of those parallel runs have a faulty connection or open up, you'd have a severely underwired circuit that could burn your house down. Our first house had the electric furnace wired that way because it was located in an area were Code and inspections were not required.
Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).
R.I.P.
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).
R.I.P.
-
Robert Reed
- Posts: 2277
- Joined: Wed Nov 24, 2004 1:01 am
- Location: ASHTABULA,OHIO
- Contact:
Good post Dean
But just a few afterthoughts here. It is not uncommon to measure the neutal lead voltage to ground at the outlet and see a 2-3 volt potential here, when under a moderately heavy load. In fact this is almost mandatory with long runs (>50 ft.) and can be easily verified with Ohms law. Delta Systems can and sometimes do have a neutral wire. All points of their vector triangle are referenced to neutral and this is smack dead center of the triangle when load is perfectly balanced. "Y" or star systems operate many times without using a neutral. Almost all power company distribution systems prior to the '60s used 5 KV Delta running down residential neighborhoods. Almost all dist. systems that are post '60s run "Y" 13.2 KV on their poles for the same residential service. Neither system is carrying a neutral as they both operate phase to phase. You as an individual will normally see only two of these phase conductors running by your house. Please don't think I am nitpicking here - just thought I would throw this in as a bit of trivia.
But just a few afterthoughts here. It is not uncommon to measure the neutal lead voltage to ground at the outlet and see a 2-3 volt potential here, when under a moderately heavy load. In fact this is almost mandatory with long runs (>50 ft.) and can be easily verified with Ohms law. Delta Systems can and sometimes do have a neutral wire. All points of their vector triangle are referenced to neutral and this is smack dead center of the triangle when load is perfectly balanced. "Y" or star systems operate many times without using a neutral. Almost all power company distribution systems prior to the '60s used 5 KV Delta running down residential neighborhoods. Almost all dist. systems that are post '60s run "Y" 13.2 KV on their poles for the same residential service. Neither system is carrying a neutral as they both operate phase to phase. You as an individual will normally see only two of these phase conductors running by your house. Please don't think I am nitpicking here - just thought I would throw this in as a bit of trivia.
Who is online
Users browsing this forum: No registered users and 65 guests