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

Thu Jun 20 20:20:45 PDT 2013

I am thinking of running a #4 AL neutral.

At 04:35 PM 6/20/2013, you wrote:
>Unfortunately, the benefits are somewhat limited since you still 
>have to size the neutral at the same size as your EGC, and you have 
>to upsize your EGC thanks to your voltage drop. So now instead of a 
>#6 neutral, you're running them as 8s? Hey, every bit helps...
>
>
>
>On 2013/6/20 16:18, Drake wrote:
>>Hi Wallace,
>>
>>For services, at least, in the 2011 NEC, the neutral is still sized per
>>Table 250.66 (250.24 (C) (1).
>>
>>I took Allan's suggestion and called Power One tech support back. The
>>neutral carries no current; it is strictly for sensing.
>>
>>Drake
>>
>>At 02:23 PM 6/20/2013, you wrote:
>>>Drake,
>>>
>>>Full sized neutrals are now required due to harmonics at least.
>>>
>>>The cost over your quote for neutral is fixed. What is the cost for
>>>unknown consequences if you disregard manufacturers specs?
>>>
>>>Wallace Stahle
>>>Future Electric Energy Co
>>>P O Box 236
>>>Willits, CA 95490
>>>future at pacific.net <mailto:future at pacific.net>
>>>CA Lic.# C10-762093
>>>707-459-0474
>>>
>>>
>>>On Jun 19, 2013, at 3:26 PM, Drake wrote:
>>>
>>>>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*
>>>>>_Allan at positiveenergysolar.com <mailto: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 Corporation^TM
>>>>>3209 Richards Lane
>>>>>Santa Fe, New Mexico 87507
>>>>>*505 424-1112 office 780-2738 cell*
>>>>>_www.positiveenergysolar.com <http://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
>>>>>>>john at renewableassociates.com <mailto:john at renewableassociates.com>
>>>>>>>www.renewableassociates.com <http://www.renewableassociates.com/>
>>>>>>><2221ada.jpg>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>*From:* re-wrenches-bounces at lists.re-wrenches.org
>>>>>>><mailto: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:* re-wrenches at lists.re-wrenches.org
>>>>>>><mailto: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/
>>>>>>>
>>>>>>>
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>>>>>>
>>>>>>
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