multiple circuit neutrals tied together

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Tying neutrals of different circuits together is effectively paralleling wire, which unless larger than 1/0 is also a violation of 310.4.

300.3 references 310.4, tho 300.3 says all conductors of a circuit must be in the same cable, raceway, etc unless allowed elsewhere. Even if you meet that condition, you still cannot tie 2 or more #12 neutrals together.

Nowadays you also have the fact that tying neutrals of different circuits together will mean tripped AFCI breakers and the time lost troubleshooting them.

eta: there appears to be 9 #14s under one wirenut. I do not know of any wirenut rated for that many #14s. It's also a badly done connection imo.

re: magnetic fields that are damaging, sounds like a bunch of claptrap scare tactics to oversell services.
 
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Coppersmith said:
....It says 300.3(B) is the article prohibiting it, but I don't see that in there. Can somebody educate me on this?
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(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 (B)(4).
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The point is you don't want hot coming in from one romex and going out on two romexes.

In the video it's rather obvious that there are multiple circuit neutrals under one wire nut. Other times it's not so easy to see and that can be a major safety issue..... You turn off a breaker, test for power and confirm power is off, start pulling apart splices and BAMMO, you get hit by a live neutral that is still powered up by a different circuit.

Don't ever bootleg neutrals.
 
JFletcher said:
... re: magnetic fields that are damaging, sounds like a bunch of claptrap ...
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I'm also curious to know how paralleling neutral wires increases the magnetic field strength. That same amount of current should create the same magnetic field, even if it's divided among several return paths. Ah, well, don't believe everything you see on the Internet.
 
drcampbell said:
I'm also curious to know how paralleling neutral wires increases the magnetic field strength. That same amount of current should create the same magnetic field, even if it's divided among several return paths. Ah, well, don't believe everything you see on the Internet.
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But those return paths are not in the same proximity. Two wires close together with equal yet opposite fields cancel out. Ie 5 amps L1 and 5amps N= 0. However, differing magnitudes do not result in a zero field. 5 amps on L1 and 2.5amps on N result in a 2.5amps without an opposing field to cancel out and in turn very high EMF. Its been shown that building wiring errors can produce magnetic fields exceeding power lines.

FWIW Just think how a GFCI works...
 
drcampbell said:
I'm also curious to know how paralleling neutral wires increases the magnetic field strength. That same amount of current should create the same magnetic field, even if it's divided among several return paths. Ah, well, don't believe everything you see on the Internet.
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There is a magnetic field between conductors of the same circuit but when you run conductors in the same conduit or same cable the magnetic field is basically canceled. Separate them and the field becomes as large as the distance between those wires. K&T wiring is a great example of how the field is increased.
 
I agree it is against code. If circuit #1 breaker is feeding certain outlets And neutral of circuit #2 is path of least resistance electrons from ckt#1 will flow on ckt#2. I find this problem all the time. They must not be teaching it in school. Never heard of it in any school I went to. Was taught on the job to tie all neutrals together. figured it out on my own.

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Tho a code violation and will play havoc with AFCI breaker, tying neutrals together of different circuits, especially if the hots are on different legs, *could* create a more reliable circuit. Example:

House with 120/240V (split phase) service has two branch circuits, one on each leg, that draw 10A each, on say #14 wire. Individually (wired correctly), each hot carries 10A, and each independent neutral carries 10A. Magnetic fields cancelled.

Now, tie the neutrals together. Each #14 hot still carries 10A, but the 2 #14 neutrals together carry 0A current. Even if one fails, the remaining neutral for the 2 circuits only carries the imbalance of current between the two hots. Magnetic fields ??? depending on wire pathing back to the panel. Not like you're going to get insta-cancer or have your head explode ala the movie "Scanners".

I disagree with 310.4 when paralleling is done for reliability rather than ampacity reasons. No one is going to run 2 #14s to each terminal of a 14-30R for a dryer, but using 2 #14s when one is called for shouldnt be a violation imho.
 
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Daniel malack said:
So now we have a circuit if on the same phase breakered at 15 amps potentially delivering 29 amps on a # 14awg and not tripping! ?

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Potentially delivering 50+ amps. A 15A breaker will not trip at 15A. A 15A breaker can carry 25A for quite a while before it trips. If two circuits on the same leg were sharing a neutral, that neutral could possibly melt before the OCPD of either circuit tripped.
 
Dennis Alwon said:
There is a magnetic field between conductors of the same circuit but when you run conductors in the same conduit or same cable the magnetic field is basically canceled. Separate them and the field becomes as large as the distance between those wires. K&T wiring is a great example of how the field is increased.
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CAREFUL! You will give away Tesla's big secret of how he was going to provide electricity to everyone without power lines! Gotta remember electricity maybe doesn't flow IN the wires but rather around them in the fields... Why everyone knows electron flow IN the wire is only about 30 inches per hour...
 
Daniel malack said:
Ah! So we can now see that the original question creates multiple problems. Their for the code is correct to establish that commandment!

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Looked at video again. Someone said that it was biologically damaging. How halerous. If he knows it is a violation, why say something so Stupid? Biological damaging!

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Daniel malack said:
Looked at video again. Someone said that it was biologically damaging. How halerous. If he knows it is a violation, why say something so Stupid? Biological damaging!

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Watched it again and cause of biological damage was from large magnetic fields. My thought is that the magnetic field would collapse traveling on a neutral of another circuit?

I think I'm talking to myself!

Any comments?

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Daniel malack said:
Watched it again and cause of biological damage was from large magnetic fields. My thought is that the magnetic field would collapse traveling on a neutral of another circuit?
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If the neutral was not in close proximity to a conductor to cancel current flow there would be an EMF issue along the path of the current flow. EMF is suspect in childhood leukemia although there are arguments on both sides of this. One thing for sure is it can cause issues with electronics.


Roger
 
I don't know about lucemia, but this issue should be taught in electrical classes. There is a lot of reasons to keep the circuit wires together on its own! It's a circuit. Not a circuit with an extension.

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Sometimes I find the concentric neutral on risers coming out of substations carrying 100-200 volts. Technically the insulation is supposed to prevent that, but after years of sitting in water it deteriorates.
I always wonder what temperature the conduit is, im gonna have to break out the infrared gun.

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Daniel malack said:
Looked at video again. Someone said that it was biologically damaging. How halerous. If he knows it is a violation, why say something so Stupid? Biological damaging!

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Click to expand...

Its debated and studies go both ways. His comment does technically hold some water based on what he stands on. But here is the easy part: when wired to code we don't have to debate that because the fields disappear.
 
Daniel malack said:
Watched it again and cause of biological damage was from large magnetic fields. My thought is that the magnetic field would collapse traveling on a neutral of another circuit?

I think I'm talking to myself!

Any comments?

Sent from my SM-T350 using Tapatalk
Click to expand...


Current going in must equal current going out. 10 amps on the hot and 10amps on the neutral in the same romex cable cancels out. Now if you tie neutrals together, that current splits because electricity takes all paths back to the source. Now instead of 10 and 10 amps you have 10 and 5 amps in the same jacket. The 10 amp filled will "over power" the 5 amp field and makes itself known in terms of high EMF.

Not to confuse, but think about how a GFCI operates... or why a clamp on amp meter will not work with multiple conductors underneath it.
 
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