# 200% neutral



## Dennis Alwon

Generally you see these in communication and computer builders wherte there are a lot of non linear loads


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## spark-ski

Harmonics maybe? Lots of computers, printers, servers? Nice panel trim out by the way


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## eddy current

Was two 42 cct panels. New tenant fit-up needed 25 more ccts but panels were full


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## Dennis Alwon

You get a sense for it here



> 310.15(B)(%)(c) On a 4-wire, 3-phase wye circuit where the major
> portion of the load consists of nonlinear loads, harmonic
> currents are present in the neutral conductor; the neutral
> conductor shall therefore be considered a current-carrying
> conductor.


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## eddy current

Yes denis and spark ski, most of that building is occupied by computer based companies


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## zac

Nice work.
Looks like the cover is going to be an issue getting on.


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## Southeast Power

Every PDU I have ever opened or wired was 200% neutral.


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## Southeast Power

eddy current said:


> Alot of the installs I do, the engineer asks for oversized neutral. Office buildings mainly. Anyone else seeing many of these?
> Here's a pic of a panel swap I did yesterday that had one.
> Swapped a 42 cct for a 66 cct.


I know its piped but, I find it interesting that they called for 200% neutral but, not a ground wire between the two panels.


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## Bad Electrician

I have said it before and I'll say it again, nice way to make extra money, good for the bottom line, also the Copper Council appreciates it. But I have done literally 1000's of site surveys and have only seen neutral current exceed the phase currents a few times and that was because the transformer was overloaded exceeding 100%.

In my experience sites were the neutral is sized at 200% the engineer also installs a distribution system loaded to a maximum of 30%.

Not saying I am against this practice, just have not seen the need in properly designed, properly installed and maintained electrical distribution systems.


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## eddy current

jrannis said:


> I know its piped but, I find it interesting that they called for 200% neutral but, not a ground wire between the two panels.


#6 Bond between panels installed after the first pic was taken. You can kinda see it on the left side of the big panel in second pic.


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## chicken steve

Most of our amp probes went true rms back when the nec learned how to play _harmonica_ when the copper cabal debuted the super noodle cable on us.....something near a dz nec references within a short time span iirc










So we all went out with the same sales shtick , looking to retrofit _harmonica_ 20 yrs ago , which sells about as good these days

The only prob being, a multitude of retros haven't proven it _necessary _since:no:.....that said, teach 'em young......:laughing:


https://www.youtube.com/watch?v=26c8B6rgSTY

~CS~


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## RIVETER

eddy current said:


> Alot of the installs I do, the engineer asks for oversized neutral. Office buildings mainly. Anyone else seeing many of these?
> Here's a pic of a panel swap I did yesterday that had one.
> Swapped a 42 cct for a 66 cct.


If they pay you extra to put more in...why not. Properly installed wiring systems don't need it.


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## Meadow

Can those be double lugged like that in Canada?


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## nrp3

Assuming it has the oval opening for two conductors?


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## cabletie

I don't think I have seen a 200% neutral on new installs in ten years. I think the engineers have finally caught on. Most specs call for separate neutrals for branch circuits. It has been like that since well before the handle tie code for multi-wire circuits was in effect.


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## Bad Electrician

cabletie said:


> I don't think I have seen a 200% neutral on new installs in ten years. I think the engineers have finally caught on. Most specs call for separate neutrals for branch circuits. It has been like that since well before the handle tie code for multi-wire circuits was in effect.


Mostly government jobs these days for all three phase, 3 wire loads, no neutrals AND YES I HAVE SEEN THAT.


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## RIVETER

Dennis Alwon said:


> Generally you see these in communication and computer builders wherte there are a lot of non linear loads


Do you believe that that compensation is necessary?


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## KDC

If you have a sufficient number of non linear loads, which are getting more and more common, there's going to triplens. 

And we're seeing more and more non linear loads as we go to LEDs on top of all the switchmode power supplies and electronics ballasts. 

Still takes a lot though.


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## Bad Electrician

KDC said:


> If you have a sufficient number of non linear loads, which are getting more and more common, there's going to triplens.
> 
> And we're seeing more and more non linear loads as we go to LEDs on top of all the switchmode power supplies and electronics ballasts.
> 
> Still takes a lot though.


Read my post regarding harmonics in 3 phase distribution systems, and the issue based on my experience over blown. I have been doing harmonic surveys since the late 70's. There were quite a few issues in the early days particularly with drives on transformers and with early generation electronic protective devices. Then as time went on issues with harmonics were either from overload distribution systems or systems that were operating on generator were equipped with old voltage regulators and governors that could not cope with the excessive voltage distortion.


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## RIVETER

Bad Electrician said:


> Read my post regarding harmonics in 3 phase distribution systems, and the issue based on my experience over blown. I have been doing harmonic surveys since the late 70's. There were quite a few issues in the early days particularly with drives on transformers and with early generation electronic protective devices. Then as time went on issues with harmonics were either from overload distribution systems or systems that were operating on generator were equipped with old voltage regulators and governors that could not cope with the excessive voltage distortion.


Are you saying that the weird currents from non linear loads are akin to Standing Wave Ratios in RF transmission?


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## Bad Electrician

Riv

What I am saying is With high I-THD, there is V-THD, the generator source is not as stiff as the utility so what could be 2-3% V-THD on utility can be much higher when the site transfers to generator. This high Voltage Distortion causes issues with older governors and voltage regulators.


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## RIVETER

Bad Electrician said:


> Riv
> 
> What I am saying is With high I-THD, there is V-THD, the generator source is not as stiff as the utility so what could be 2-3% V-THD on utility can be much higher when the site transfers to generator. This high Voltage Distortion causes issues with older governors and voltage regulators.


Then I am right...yes?


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## Spark Master

I've seen in once with electronic ballast. I wonder if LED's will led to more of this.


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## Bad Electrician

Spark Master said:


> I've seen in once with electronic ballast. I wonder if LED's will led to more of this.


Seen what?


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## Spark Master

Bad Electrician said:


> Seen what?


 A burned neutral.


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## cuba_pete

Spark Master said:


> A burned neutral.


Highly unlikely unless the NEC would allow down-sizing the neutrals for dedicated LED lighting circuits.

You would already be seeing this with the myriad of SMPS' used for computers et al.


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## adonkle

Spark Master said:


> A burned neutral.


A lot of modern SMPS's and LED's also have built-in PFC, so that reduces their harmonics and the need for 200% neutral.


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## Shockdoc

I still drop my neutrals one size after the main disco. Never had a neutral burn out.


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