Maximum Number of disconnects Art 690.14(C)(4)

[TH Design]

In the 2012 NEC Atr 690.14(C)(4) Maximum number of disconnects shall consist of no more than six switches or six circuit breakers in a single enclosure. My question is what if there are more than 6 different systems in one building? IE photovaltaic panel arrays, Wind turbines, solar tree?

 

[jaggedben]

This is for dc conductors of a PV system. I think each inverter is a separate system, and the maximum of six dc handles applies separately to each inverter. Wind and other things are not covered in 690. If there were restrictions on having multiple sources, I would expect them to be in 705, but I don't think there are any.

 

[TH Design]

Number of disconnects

Number of disconnects

Ok, So I can have 8 different inverters with one each AC feed to a sub panel having 8 back fed breakers with one main feed to the utility panel? Also I guess this depends on the code being used by the AHJ.
Thank You for the response.

 

[jaggedben]

Ok, So I can have 8 different inverters with one each AC feed to a sub panel having 8 back fed breakers with one main feed to the utility panel?

Yes, this seems to be done frequently, with even more than 8 inverters.

 

[LEO2854]

Ok, So I can have 8 different inverters with one each AC feed to a sub panel having 8 back fed breakers with one main feed to the utility panel? Also I guess this depends on the code being used by the AHJ.
Thank You for the response.

You should read the whole section and make sure you understand it i believe you still must comply with the 6 disconnect rule.

690.15 Disconnection of Photovoltaic Equipment. Means
shall be provided to disconnect equipment, such as inverters,
batteries, charge controllers, and the like, from all ungrounded
conductors of all sources. If the equipment is
energized from more than one source, the disconnecting
means shall be grouped and identified.

Welcome to the forum.....:thumbsup:

 

[Marvin_Hamon]

690.14(C)(4) & (5) are not really clear and routinely loosely applied in large systems from what I have seen. It's common to have an inverter with more than 6 inputs into the inverter DC input combiner. The DC disconnect internal to the inverter is often sited as the one that complies with 690.14(C)(4) & (5) but a more rigid reading would require external disconnects that would isolated power to the inverter. The next disconnect back in a building mounted design might often be disconnecting DC string combiners on the roof that will probably not be grouped and would be more than 6 in number and that would not comply with 690.15.

The number of AC disconnects is often dictated by the utility as well as the NEC. While many interpret the NEC to allow up to 6 PV AC disconnects I know a major utility that will only allow one AC disconnect at a site that controls all the distributed generation on the site feeding the utility.