will there be any inductive heating in the following installation of a transfer switch. Stand by generator, Ferrous metal conduit, 1 phase 120/240 volt. Entering the MTS 1 conduit with a 4 wire generator feed and a second conduit containing 2 phase conductors (feeder) from the service & 2 phase conductors returning back to the load center, 1 neutral from the generator and 1 egc. If no is this allowed by the NEC?
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neutral required in a transfer switch
- Thread starter fladale
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crossman
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I made a little diagram of what I think you are doing, and took a superficial look at it. I don't see any magnetic field issues from my drawing. Can you draw and post a diagram of exactly what you have? Especially of what is happening at the panel/service. How is the service neutral getting to the panel yet the service hots are going to the transfer switch?
215.4 Feeders with Common Neutral Conductor.
(B) In Metal Raceway or Enclosure. Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral conductor shall be enclosed within the same raceway or other enclosure as required in 300.20.
(B) In Metal Raceway or Enclosure. Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral conductor shall be enclosed within the same raceway or other enclosure as required in 300.20.
crossman
Senior Member
- Location
- Southeast Texas
I don't think 215.4 applies to this one. There may be other code issues though.
crossman said:I don't think 215.4 applies to this one. There may be other code issues though.
The op is asking about feeder conductors and maybe service conductors. Feeder conductors are covered in article 215. If there are also service conductors ( i hope not) then that would be another violation.
230.7 Other Conductors in Raceway or Cable.
Conductors other than service conductors shall not be installed in the same service raceway or service cable.
crossman
Senior Member
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- Southeast Texas
230.7 is probably going to be an issue as you mention. 215.4 is for multiple feeders with a common neutral. it doesn't appear that this is that. Still, we need a diagram from the OP. I am still interested in what is happening at the panel.
crossman
Senior Member
- Location
- Southeast Texas
Fladale, have you come up with a diagram of the wiring arrangements yet? I noticed you started a new thread asking this same question this morning.
Most all forum members review all of the various forum categories here at MH. You will get plenty of help right here on this thread if you can give us more info and a drawing.
Most all forum members review all of the various forum categories here at MH. You will get plenty of help right here on this thread if you can give us more info and a drawing.
crossman said:215.4 is for multiple feeders with a common neutral.
Where do you see multiple?
(B) In Metal Raceway or Enclosure. Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral conductor shall be enclosed within the same raceway or other enclosure as required in 300.20.
If the sentence had said conductor and feeder, it would not make sense.
I am not sure how to draw a picture and send it. This installation includes adding a generator to an existing dwelling. The existing feeder phase conductors were removed from the line terminals of the existing panel and buged onto 2 new wires that go to 1 of the inputs on a MTS. The existing neutral was not extended to the MTS. The other input in the MTS was connected to the 2 phase conductors from the generator, the neutral from the generator was run to the neutral bar in the existing panel. 2 new phase conductors were run from the common of the MTS to the existing panel line terminals. All egc were run as neededcrossman said:I made a little diagram of what I think you are doing, and took a superficial look at it. I don't see any magnetic field issues from my drawing. Can you draw and post a diagram of exactly what you have? Especially of what is happening at the panel/service. How is the service neutral getting to the panel yet the service hots are going to the transfer switch?
hope this helps thanks Don
RUWired said:The op is asking about feeder conductors and maybe service conductors. Feeder conductors are covered in article 215. If there are also service conductors ( i hope not) then that would be another violation.
230.7 Other Conductors in Raceway or Cable.
Conductors other than service conductors shall not be installed in the same service raceway or service cable.
There are no service conductros involved with this installation only feeder conductors. If inductive heating is not going to take place why would the code not allow this?
Thanks fladale
It sounds like your making a switch leg out of the feeder conductors. If you break down the referenced 300.20 article, you should be ok with the install.(Where used),
300.20 Induced Currents in Ferrous Metal Enclosures or Ferrous Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in ferrous metal enclosures or ferrous metal raceways, they shall be arranged so as to avoid heating the surrounding ferrous metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
Where are the feeder conductors coming from that you are splicing in the panel?
Rick
300.20 Induced Currents in Ferrous Metal Enclosures or Ferrous Metal Raceways.
(A) Conductors Grouped Together. Where conductors carrying alternating current are installed in ferrous metal enclosures or ferrous metal raceways, they shall be arranged so as to avoid heating the surrounding ferrous metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be grouped together.
Where are the feeder conductors coming from that you are splicing in the panel?
Rick
Rick,
I have to disagree with you on this one. The grounded conductor is being
used and IMO should be run with the feeder. Agian, JMO, I think they put in
the "where used" to make it clear that on a 3ph 4wire system where the
feeder was only used for 3ph loads, that the grounded conductor need not be
required to be run, ( or any similar situation )
I'm more concerned on how the OP grounded/bonded this set-up, mostly at
the generator N/Gd.
I have to disagree with you on this one. The grounded conductor is being
used and IMO should be run with the feeder. Agian, JMO, I think they put in
the "where used" to make it clear that on a 3ph 4wire system where the
feeder was only used for 3ph loads, that the grounded conductor need not be
required to be run, ( or any similar situation )
I'm more concerned on how the OP grounded/bonded this set-up, mostly at
the generator N/Gd.
crossman
Senior Member
- Location
- Southeast Texas
RUWired said:Where do you see multiple?
Look at the title of 215.4 and look at 215.4(A) and you will understand that this section is referring to a specialized installation where more than one feeder (multiple) share a common neutral. This section is concerning installations of, say, three seperate feeders, each with A, B, and C conductors, and all three feeders sharing a common neutral, so: ABC, ABC, ABC, and one neutral.
crossman
Senior Member
- Location
- Southeast Texas
RUWired said:It sounds like your making a switch leg out of the feeder conductors. If you break down the referenced 300.20 article, you should be ok with the install.(Where used),
Exactly. That is the way I envision it. I would still like to see a diagram. The OP said the service wires were mixed with the feed back from the xfer switch. Then he said they weren't.
benaround said:Rick,
I have to disagree with you on this one. The grounded conductor is being
used and IMO should be run with the feeder. Agian, JMO, I think they put in
the "where used" to make it clear that on a 3ph 4wire system where the
feeder was only used for 3ph loads, that the grounded conductor need not be
required to be run, ( or any similar situation )
.
I think,,,The article means if your going to run the full boat, i has to run with the cable or raceway, not outside of it or as in the one post ,via messenger cable.We're able to run switch legs in branch wiring so i don't see this being much different. Both phase conductors in this case are being run in the same conduit.
what do you think?
crossman said:Look at the title of 215.4 and look at 215.4(A) and you will understand that this section is referring to a specialized installation where more than one feeder (multiple) share a common neutral. This section is concerning installations of, say, three seperate feeders, each with A, B, and C conductors, and all three feeders sharing a common neutral, so: ABC, ABC, ABC, and one neutral.
215.4 A and B are seperate paragraphs. If (B) was in or numbered under (A), i would agree.Of course i could be "not be understanding".I did'nt know you could run multiple feeders with a common neutral.
Rick
crossman
Senior Member
- Location
- Southeast Texas
RUWired said:215.4 A and B are seperate paragraphs. If (B) was in or numbered under (A), i would agree.Of course i could be "not be understanding".I did'nt know you could run multiple feeders with a common neutral.
Okay. Read the title of 215.4. That certainly narrows down (B) to discussing multiple feeders with a common neutral. Yes, I threw the "multiple" in there to enhance understanding. 215.4 is talking about multiple feeders with a common neutral. I am absolutely certain about this.
I am still in agreement with you on the switch-leg analogy, and that the magnetic fields would be okay.:smile:
RUWired said:I think,,,The article means if your going to run the full boat, i has to run with the cable or raceway, not outside of it or as in the one post ,via messenger cable.We're able to run switch legs in branch wiring so i don't see this being much different. Both phase conductors in this case are being run in the same conduit.
what do you think?
I think the switch leg thing makes perfect sense, but 300.3 and 300.5(I)
make me think that the NEC does not like it.
I'd still like to know the OP's grounding/bonding scheme.
crossman
Senior Member
- Location
- Southeast Texas
The key to both those sections is the words "where used" before "grounded conductor". What this means is that the grounded conductor doesn't have to be pulled where it isn't used, and this is most likely speaking of switch legs. The neutral doesn't have to be pulled to a switch if the switch doesn't require it, and we can meet the requirements of 300.20 for magnetic fields.
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