[RE-wrenches] Full sized neutral - 240 V inverter

[Drake]

That was my first call. They said use a full size neutral. I'm not 
satisfied with that answer. The combined experience and knowledge on 
this list far exceeds that of any tech support person.

At 04:27 PM 6/19/2013, you wrote:
>Drake,
>Why not discuss this with Power One tech support?
>Allan
>
>Allan Sindelar
><mailto:Allan at positiveenergysolar.com>Allan at positiveenergysolar.com
>NABCEP Certified PV Installation Professional
>NABCEP Certified Technical Sales Professional
>New Mexico EE98J Journeyman Electrician
>Founder and Chief Technology Officer
>Positive Energy, Inc., a Certified B CorporationTM
>3209 Richards Lane
>Santa Fe, New Mexico 87507
>505 424-1112 office 780-2738 cell
><http://www.positiveenergysolar.com/>www.positiveenergysolar.com
>
>On 6/19/2013 1:55 PM, Drake wrote:
>>A very common cable for 100 A service conductors has 2 - #2 AL 
>>wires and 1 - #4 AL for the neutral;  200 A will have 2 - 4/0 AL 
>>wires and 1 - 2/0 for the neutral.   If I run # 2 to limit the VD 
>>on the run to the panel and reduce the neutral to #4, #12 copper 
>>phase and neutral will still connect to the inverters.  This would 
>>be code for a feeder to a separate structure.
>>
>>Does the Power One inverter actually have a major imbalance 
>>resulting in substantial neutral currents? If so, it is really a 
>>120 V inverter for VD calculations.
>>
>>
>>  03:37 PM 6/19/2013, you wrote:
>>>Content-Type: multipart/related;
>>>         boundary="----=_NextPart_000_00A6_01CE6CE9.D20EFB20"
>>>Content-Language: en-us
>>>
>>>Doug,
>>>705.95(B) allows you down size your neutral if it is used solely 
>>>for instrumentation and it must be sized equal to or larger than 
>>>the EGC but this is not the case. If Power One says a full size 
>>>neutral is needed than that means that it is not just a voltage 
>>>sensing conductor used for instrumentation and that it does carry current.
>>>
>>>I don't believe there are any exceptions in code for downsizing 
>>>your neutral in regards to upsizing the conductors to account for 
>>>voltage drop but I could be wrong.
>>>
>>>--
>>>John Stimac | Corvallis, OR
>>>Renewable Energy Associates LLC
>>>541-754-2001 Office/Fax
>>><mailto:john at renewableassociates.com>john at renewableassociates.com
>>>www.renewableassociates.com
>>>REAL_logo_black2
>>>
>>>
>>>
>>>
>>>From: 
>>><mailto:re-wrenches-bounces at lists.re-wrenches.org>re-wrenches-bounces at lists.re-wrenches.org 
>>>[ mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Drake
>>>Sent: Wednesday, June 19, 2013 6:42
>>>To: 
>>><mailto:re-wrenches at lists.re-wrenches.org>re-wrenches at lists.re-wrenches.org
>>>Subject: [RE-wrenches] Full sized neutral - 240 V inverter
>>>
>>>Hello Wrenches,
>>>
>>>Power One tech support said that full sized neutrals had to be run 
>>>to a pair of 240 V, PVI 3.6 inverters.  We have a 180 foot 
>>>underground run to the service panel.
>>>
>>>Why do we need to run a full sized neutral all the way back to the 
>>>panel?  The wiring to the panel is oversized for voltage 
>>>drop.  The code allows for reduction of neutral size where neutral 
>>>imbalance is less than the current of a phase, which is usually the case.
>>>
>>>Why does a neutral need to be installed that is the size of the 
>>>phase wiring where the imbalance should be negligible? Or is there 
>>>a lot of neutral current for some reason?  Am I missing something?
>>>
>>>Thanks
>>>
>>>Drake
>>>
>>>
>>>Drake Chamberlin
>>>Athens Electric LLC
>>>OH License 44810
>>>CO License 3773
>>>NABCEP Certified Solar PV Installer
>>>740-448-7328
>>><http://athens-electric.com/>http://athens-electric.com/
>>>
>>>
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