WAG... 11 ? 3 array.
what does WAG mean?
OK to downsize OCPD
- Thread starter csoc64
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what does WAG mean?
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- Placerville, CA, USA
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- Retired PV System Designer
And SWAG refers to Scientific WAG. Or in the following case, Sarcastic WAG:
11 x 3? SWAG 3 x 11!
11 x 3? SWAG 3 x 11!
Wrongway
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- Vacaville, ca USA
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Enphase 250 micro inverters are rated at 1A per micro giving you 33 Amps x the 1.25 factor = 41.25. If you use the 33x250 watt/240v= 34.37a. Do you still have to times it by the 1.25 factor?
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Enphase 250 micro inverters are rated at 1A per micro giving you 33 Amps x the 1.25 factor = 41.25. If you use the 33x250 watt/240v= 34.37a. Do you still have to times it by the 1.25 factor?
Yes... but no.
The "no" has priority because we are required to use the inverter output current rating.
earshavewalls
Senior Member
2011 NEC, Article 705.12(7) indicates that the 1st OCPD after the inverter is to be used for all busbar and conductor calculations. Whatever OCPDs they are using at the subpanel would "wag the dog" as far as the OCPD at the main service. In fact, the OCPD at the main service could use any OCPD value up to the rating of the subpanel and this would be fully compliant as long as the 1st OCPDs total values did not exceed 120% of the busbar rating at the main or at the subpanel. We are not yet under the 2014 NEC (California), so I am not sure what that editions says on this matter.
ggunn
PE (Electrical), NABCEP certified
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- Austin, TX, USA
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- Consulting Electrical Engineer - Photovoltaic Systems
Under 2014 I believe you are allowed to use 125% of the summed rated output of the inverters to calculate the 120% rule rather than the ratings of the first OCPD's seen by the inverters.
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