[RE-wrenches] neutral sizing for sense

Tue Jan 25 09:24:00 EST 2022

Drake,
I believe that is for a single phase 2 wire output only. I am assuming one
hot and one neutral for the inverter output in this case. I would think
most *grid tied* inverters fall under 705.95B, where the neutral is only a
voltage sense and can be sized as small as the equipment ground.
Cheers,
Dave

On Tue, Jan 25, 2022, 8:37 AM <drake.chamberlin at redwoodalliance.org> wrote:

> "the maximum load connected between the neutral and any one ungrounded
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ungrounded> conductor
> plus the inverter
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/6/special-equipment#inverter> output
> rating shall not exceed the ampacity
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ampacity> of
> the neutral conductor
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#neutral_conductor>
> ."
>
>
> So the neutral conductor is supposed to be sized for the connected load
> plus the entire maximum output of the inverter?
> ---
>
>
>
> On 2022-01-24 12:10, Kirk Herander wrote:
>
> 705.95 Ampacity of Neutral Conductor
> National Electrical Code 2017 of New York State
> <https://up.codes/viewer/new_york/nfpa-70-2017> > 7 Special Conditions
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/7/special-conditions#7>
>  > 705 Interconnected Electric Power Production Sources
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/7/special-conditions#705>
>  > 705.95 Ampacity of Neutral Conductor
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/7/special-conditions#705.95>
> JUMP TO FULL CODE CHAPTER
>
> The ampacity
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ampacity> of
> the neutral conductors
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#neutral_conductor> shall
> comply with either (A) or (B).
>
>
> (A) Neutral Conductor for Single Phase, 2-Wire Inverter Output
> <#m_3695074346584270383_NOP>
>
> If a single-phase, 2-wire
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/8/communications-systems#wire>
>  inverter
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/6/special-equipment#inverter> output
> is connected to the neutral and one ungrounded
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ungrounded> conductor
> (only) of a 3-wire
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/8/communications-systems#wire> system
> or of a 3-phase, 4-wire
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/8/communications-systems#wire>,
> wye-connected system, the maximum load connected between the neutral and
> any one ungrounded
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ungrounded> conductor
> plus the inverter
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/6/special-equipment#inverter> output
> rating shall not exceed the ampacity
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ampacity> of
> the neutral conductor
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#neutral_conductor>
> .
>
>
> (B) Neutral Conductor for Instrumentation, Voltage, Detection or Phase
> Detection <#m_3695074346584270383_NOP>
>
> A conductor used solely for instrumentation, voltage
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#voltage_of_a_circuit> detection,
> or phase detection and connected to a single-phase or 3-phase interactive
> inverter
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#interactive_inverter>,
> shall be permitted to be sized at less than the ampacity
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#ampacity> of
> the other current-carrying conductors and shall be sized equal to or larger
> than the equipment grounding conductor
> <https://up.codes/viewer/new_york/nfpa-70-2017/chapter/1/general#grounding_conductor_equipment_egc>
> .
>
> On Mon, Jan 24, 2022 at 11:58 AM Foxfire Energy <dan at foxfire-energy.com>
> wrote:
>
> I'd start with the manufacturers recommendations
>
> Sent from my iPhone
>
> > On Jan 24, 2022, at 11:52 AM, jay <jay.peltz at gmail.com> wrote:
> >
> > HI All,
> >
> > Where do I find in the code how to size a sense only neutral wire for GT
> inverter.
> >
> > thanks
> >
> > jay
> >
> > peltz power
> >
> >
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> --
>
> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>
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