i have a situation where my panel is on one side of my electrical room and the lighting contactor is on the other side of the room. i have raceways established for the hots to travel from the gutter to the contactor then back to the original gutter and out to the field installed lighting fixture. is there any reason to or not to include the neutrals in these runs across the room? they (the neutrals in question) arent needed in the lighting contactor, so is there any other reason to include them in the run? thank you in advance for any and all replies!
neutrals and lighting contactors
- Thread starter cjole
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- Status
- Location
- Massachusetts
Re: neutrals and lighting contactors
As long as the hots go to and from the contactors back to the panel in the same raceway it is fine. 300.20
As long as the hots go to and from the contactors back to the panel in the same raceway it is fine. 300.20
Re: neutrals and lighting contactors
Could you explain that a little more Iwire? Somewhere in there he has to get to the lighting fixtures.I can see where when the wiring leaves the load side of the contactors the circuits could go through several different conduits to the lighting fixtures.
[ September 29, 2004, 09:13 AM: Message edited by: jap2525 ]
Could you explain that a little more Iwire? Somewhere in there he has to get to the lighting fixtures.I can see where when the wiring leaves the load side of the contactors the circuits could go through several different conduits to the lighting fixtures.
[ September 29, 2004, 09:13 AM: Message edited by: jap2525 ]
jcross
Member
- Location
- Piney Flats, TN
Re: neutrals and lighting contactors
300.3 Conductors.
(A) Single Conductors. Single conductors specified in Table 310.13 shall only be installed where part of a recognized wiring method of Chapter 3.
(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
300.20 Induced Currents in Metal Enclosures or Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in metal enclosures or metal raceways, they shall be arranged so as to avoid heating the surrounding metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
Doesn't this mean the neutrals have to be included?
300.3 Conductors.
(A) Single Conductors. Single conductors specified in Table 310.13 shall only be installed where part of a recognized wiring method of Chapter 3.
(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
300.20 Induced Currents in Metal Enclosures or Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in metal enclosures or metal raceways, they shall be arranged so as to avoid heating the surrounding metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
Doesn't this mean the neutrals have to be included?
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: neutrals and lighting contactors
If you run a circuit in the ceiling above the dining room, and there is a ceiling light that is controlled by a wall switch, how do you run wires to the switch? I think you run a hot from the ceiling area, down the wall to the switch, then back up the wall to the ceiling area, and finally go to the light. I don?t think you run the neutral with the wires going down and up the wall to the switch. Am I right about this? And is this not the same thing as cjole?s question?
As to having a single phase conductor (and no neutral) causing heating in a metal raceway, that would not be a problem (at least from the physics point of new). The current goes one way to the contactor and the other way back to the gutter. The magnetic fields of the two paths would essentially cancel each other out.
If you run a circuit in the ceiling above the dining room, and there is a ceiling light that is controlled by a wall switch, how do you run wires to the switch? I think you run a hot from the ceiling area, down the wall to the switch, then back up the wall to the ceiling area, and finally go to the light. I don?t think you run the neutral with the wires going down and up the wall to the switch. Am I right about this? And is this not the same thing as cjole?s question?
As to having a single phase conductor (and no neutral) causing heating in a metal raceway, that would not be a problem (at least from the physics point of new). The current goes one way to the contactor and the other way back to the gutter. The magnetic fields of the two paths would essentially cancel each other out.
Re: neutrals and lighting contactors
That's what raised my question to iwire's response.There is a good chance that the lighting contactor would have multiple conduits stubbed up into the gutter (for kicks lets say (2) 3/4's).Is he saying that the line and load conductors of the same circuit to the contactor enclosure would all have to be installed in the same conduit? is it a code violation to install the line conductors in one conduit and the switchlegs in the other?
That's what raised my question to iwire's response.There is a good chance that the lighting contactor would have multiple conduits stubbed up into the gutter (for kicks lets say (2) 3/4's).Is he saying that the line and load conductors of the same circuit to the contactor enclosure would all have to be installed in the same conduit? is it a code violation to install the line conductors in one conduit and the switchlegs in the other?
Re: neutrals and lighting contactors
Jcross,(where used) the neutrals are not used in the lighting contactors for the lighting only for the coil (if 120v).the contactor is only for switching the phase conductors not the neutral.by the code statement you would think we'd need to bring the neutrals with them,but where do we land them if we do? wire nut them in the lighting contactor enclosure? that gets messy. I've had guys wanting to pull a larger neutral to the lighting contactors from the panel and land it on a neutral bar located in the lighting contactor just for this purpose.On the other hand most generally the circuits to the lighting fixtures are piped directly to the lighting contactor,therefor containing the neutrals with them to the fixtures and there is no choice but to pull neutrals along with the circuits feeding the line side of the contactors from the panel and join the neutrals in the lighting contactor enclosure.(it all depends on how the installation is piped).I would like to know the proper way to do this and clear up some of the confusion.
[ September 29, 2004, 01:50 PM: Message edited by: jap2525 ]
Jcross,(where used) the neutrals are not used in the lighting contactors for the lighting only for the coil (if 120v).the contactor is only for switching the phase conductors not the neutral.by the code statement you would think we'd need to bring the neutrals with them,but where do we land them if we do? wire nut them in the lighting contactor enclosure? that gets messy. I've had guys wanting to pull a larger neutral to the lighting contactors from the panel and land it on a neutral bar located in the lighting contactor just for this purpose.On the other hand most generally the circuits to the lighting fixtures are piped directly to the lighting contactor,therefor containing the neutrals with them to the fixtures and there is no choice but to pull neutrals along with the circuits feeding the line side of the contactors from the panel and join the neutrals in the lighting contactor enclosure.(it all depends on how the installation is piped).I would like to know the proper way to do this and clear up some of the confusion.
[ September 29, 2004, 01:50 PM: Message edited by: jap2525 ]
Re: neutrals and lighting contactors
Anytime you have a conductor carrying current, you want another conductor carrying the same current going the opposite direction. This other conductor is usually the neutral wire. But it can also be the same hot wire (going to a switch or contactor and back to the point where it left the neutral).
Mathmatically, a current produces an EMF proportional to the current and the area the current encloses. By always keeping a pair of wires (line and neutral, or line and same line returning) together, the area is kept to almost zero, and the EMF is minimized.
A diagram would be very helpful here, but I don't know how to post one.
Steve
Anytime you have a conductor carrying current, you want another conductor carrying the same current going the opposite direction. This other conductor is usually the neutral wire. But it can also be the same hot wire (going to a switch or contactor and back to the point where it left the neutral).
Mathmatically, a current produces an EMF proportional to the current and the area the current encloses. By always keeping a pair of wires (line and neutral, or line and same line returning) together, the area is kept to almost zero, and the EMF is minimized.
A diagram would be very helpful here, but I don't know how to post one.
Steve
Re: neutrals and lighting contactors
It's critically important that conduits that carry a hot to your switch (contactor) carry it's switchleg(s) back in the same conduit.
When you do so, all of the following requirements are met.
(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
300.20 Induced Currents in Metal Enclosures or Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in metal enclosures or metal raceways, they shall be arranged so as to avoid heating the surrounding metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
The hot and the switchleg are the only conductors in the circuit in a branched off conduit to a switch. Draw the circuit on a piece of paper and it's clear that the neutral is not a part of the circuit when it branches off to the switch.
[ September 29, 2004, 03:35 PM: Message edited by: sdbob ]
It's critically important that conduits that carry a hot to your switch (contactor) carry it's switchleg(s) back in the same conduit.
When you do so, all of the following requirements are met.
(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
300.20 Induced Currents in Metal Enclosures or Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in metal enclosures or metal raceways, they shall be arranged so as to avoid heating the surrounding metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
The hot and the switchleg are the only conductors in the circuit in a branched off conduit to a switch. Draw the circuit on a piece of paper and it's clear that the neutral is not a part of the circuit when it branches off to the switch.
[ September 29, 2004, 03:35 PM: Message edited by: sdbob ]
Re: neutrals and lighting contactors
Originally posted by sdbob:
Draw the circuit on a piece of paper and it's clear that the neutral is not a part of the circuit when it branches off to the switch.
The neutral is always a part of a 120v or 277v circuit it just so happens it is not extended to the switch as per the exception for a switchloop.
Originally posted by sdbob:
Draw the circuit on a piece of paper and it's clear that the neutral is not a part of the circuit when it branches off to the switch.
The neutral is always a part of a 120v or 277v circuit it just so happens it is not extended to the switch as per the exception for a switchloop.
- Location
- Massachusetts
Re: neutrals and lighting contactors
That is the reason for these words.
"where used, the grounded conductor"
The grounded conductor is not used in a switch leg.
If we say the neutral is always used in a 120 or 277 volt circuit you would have to bring it down to a switch and cap it off unused.
I do not understand, there is no exception for a 'switch loop' we do not need an exception.
That is the reason for these words.
"where used, the grounded conductor"
The grounded conductor is not used in a switch leg.
If we say the neutral is always used in a 120 or 277 volt circuit you would have to bring it down to a switch and cap it off unused.
Re: neutrals and lighting contactors
404.2 exception states switch loops shall not require a grounded conductor,as someone stated previously,they feel like a lighting contactor is part of a switch loop,which in a sense it is.All I'm saying is try running 120 volt or 277 volt lighting without the neutral terminated in the panel,will the lights come on? no,so yes the neutral is always a part of the circuit but it is not a conductor that needs to be extended to the switch.
404.2 exception states switch loops shall not require a grounded conductor,as someone stated previously,they feel like a lighting contactor is part of a switch loop,which in a sense it is.All I'm saying is try running 120 volt or 277 volt lighting without the neutral terminated in the panel,will the lights come on? no,so yes the neutral is always a part of the circuit but it is not a conductor that needs to be extended to the switch.
- Location
- Massachusetts
Re: neutrals and lighting contactors
You can not use the exception of one section and apply it to another section.
Wish I could sometimes.
You can not use the exception of one section and apply it to another section.
Wish I could sometimes.
Re: neutrals and lighting contactors
404.2 refers us to 300.20 a stating conductors shall be arranged so as to avoid heating the surrounding material by induction.To accomplish this,all phase conductors and,where used ,the grounded conductor and all equipment grounding conductors shall be grouped together.
You can say the grounded conductor is not used in the wiring directed to the switch,but,you cannot say that the neutral is not part of the circuit.Even though the neutral is not required to be brought to the switch it is still part of the circuit.
404.2 refers us to 300.20 a stating conductors shall be arranged so as to avoid heating the surrounding material by induction.To accomplish this,all phase conductors and,where used ,the grounded conductor and all equipment grounding conductors shall be grouped together.
You can say the grounded conductor is not used in the wiring directed to the switch,but,you cannot say that the neutral is not part of the circuit.Even though the neutral is not required to be brought to the switch it is still part of the circuit.
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