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

[Wallace Stahle]

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
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
>> 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
>> 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
>>>> www.renewableassociates.com
>>>> <2221ada.jpg>  
>>>>  
>>>>  
>>>>  
>>>> From: 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
>>>> 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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