690.12(C) initiation device

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asian195

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Got a question about the location of the initiation device, specifically for one and two family dwellings. Code requires it to be located outside in readily accessible location.
Most of the PV systems i see are utility interactive and shut down when the utility power is disconnected.
So if the service panel and inverter are both located inside the garage, does there need to be an external rapid shut down initiation device? Let's assume no 3rd power source (generator, batteries, energy storage, etc)

I'm trying to think as a first responder. If they pull the meter or turn main breaker off (which is already located inside the dwelling) then rapid shutdown is initiated. So why the external switch?

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I can see the external switch for stand alone systems or systems with another power source that keeps the PV system energized after disconnecting the utility service.

Hopefully someone can explain this to me. Thanks.

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asian195 said:
Got a question about the location of the initiation device, specifically for one and two family dwellings. Code requires it to be located outside in readily accessible location.
Most of the PV systems i see are utility interactive and shut down when the utility power is disconnected.
So if the service panel and inverter are both located inside the garage, does there need to be an external rapid shut down initiation device? Let's assume no 3rd power source (generator, batteries, energy storage, etc)

I'm trying to think as a first responder. If they pull the meter or turn main breaker off (which is already located inside the dwelling) then rapid shutdown is initiated. So why the external switch?

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It depends on the inverter(s). Microinverters and string inverters with optimizers are inherently rapid shutdown compliant, so you don't need a separate switch. Some string inverters provide a DC signal line that tells a rapid shutdown device when the grid is down or when the PV AC disco is opened so that it can shut down the array. You don't need a separate switch for those systems, either. With the rest, a separate rapid shutdown switch is necessary and it must be at or near the service entrance.
 
ggunn said:
It depends on the inverter(s). Microinverters and string inverters with optimizers are inherently rapid shutdown compliant, so you don't need a separate switch. Some string inverters provide a DC signal line that tells a rapid shutdown device when the grid is down or when the PV AC disco is opened so that it can shut down the array. You don't need a separate switch for those systems, either. With the rest, a separate rapid shutdown switch is necessary and it must be at or near the service entrance.
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I think his real question was...

asian195 said:
...if the service panel and inverter are both located inside the garage, does there need to be an external rapid shut down initiation device? ...
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...and under the 2017 NEC, the answer would be yes. (I'm not looking forward to this change from the 2014 NEC.)
 
jaggedben said:
I think his real question was...



...and under the 2017 NEC, the answer would be yes. (I'm not looking forward to this change from the 2014 NEC.)
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That's how read the 2017 NEC code also. It reads pretty specific. But it just doesn't seem logical to me. (In the situation i mentioned above). I get that sometimes the NEC has to write a blanket statement that will cover all possible installs, so I'm wondering if that's the situation with this code article.

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The initiator does need to be out the outside, and lots of people making the code assumed that making loss of service an initiator also made it accessible on the outside at the service entrance. Assumptions.

Here's my take, many of the people writing section 690 of the NEC are working in California where residential service disconnects are, almost always, on the outside of the house. Tell someone in California that service equipment is often inside of a house in other parts of the country and it blows their mind.
 
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Yes, 95% of residential service disconnects are inside the dwelling here in the Northeast.

2014 NEC did not specify where the RSD had to be located and some ended up in terrible locations...

2017 added outside and readily accessible...

2020 proposes to add located on the "exterior" and remove "outside" and exterior to the building that the PV system is attached...

2020 should of added that initiating device(s) shall be "grouped"
 
But if its micro inverters or optimizes doesn't the PV disco for utility operation count as the initiation device? I mean you kill grid voltage and bam system is under 60 vdc...

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Wow I didnt even consider not requiring a diso. Everywhere I've installed in kansas and missouri always requires one and some require it to be within 10 feet of the meter.

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solar.stevepvip said:
Wow I didnt even consider not requiring a diso. Everywhere I've installed in kansas and missouri always requires one and some require it to be within 10 feet of the meter.
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Some utilities allow the residential meter to be the utility PV disconnect. It was a concession to the fact that the utilities in areas with high residential PV penetration were never going to lockout those PV disconnects anyway to work on the distribution system. It's a fine idea when you have 5 houses in town with PV, not so workable when you have thousands.

Has anyone ever seen a utility lockout residential PV systems when they need to work on the distribution system? I've never seen it used.
 
I've never seen it either. I've also always found the utility disco on a typical backed system to be nuisance.seeing as they are all UL 1741 listed I've never seen the point in it.

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pv_n00b said:
Some utilities allow the residential meter to be the utility PV disconnect. It was a concession to the fact that the utilities in areas with high residential PV penetration were never going to lockout those PV disconnects anyway to work on the distribution system. It's a fine idea when you have 5 houses in town with PV, not so workable when you have thousands.

Has anyone ever seen a utility lockout residential PV systems when they need to work on the distribution system? I've never seen it used.
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It might also have been a concession to the fact they were paying too much in labor costs to have a guy go check on the existence of AC discos they were never likely to use. Let alone the hassle when the customer requested a combo for a lockbox with key to access the disco, which was an option PG&E offered. Publicly owned utilities around here still require discos because I guess no one in management is under pressure to keep those costs in check..

Important note: I believe most if not all still require a disco if there's no smart meter that can cut off current. I.e. if there's a CT meter or a three phase service.
 
jaggedben said:
It might also have been a concession to the fact they were paying too much in labor costs to have a guy go check on the existence of AC discos they were never likely to use. Let alone the hassle when the customer requested a combo for a lockbox with key to access the disco, which was an option PG&E offered. Publicly owned utilities around here still require discos because I guess no one in management is under pressure to keep those costs in check..

Important note: I believe most if not all still require a disco if there's no smart meter that can cut off current. I.e. if there's a CT meter or a three phase service.
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I figured it was the cost of a truck that only carried locks and keys for all the PV system disconnects. If the current does not go through the meter then pulling the meter won't disconnect the PV system so yes, need a disconnect. Typically on 400A and up services, I see CTs used and disconnects are needed.
 
pv_n00b said:
I figured it was the cost of a truck that only carried locks and keys for all the PV system disconnects. If the current does not go through the meter then pulling the meter won't disconnect the PV system so yes, need a disconnect. Typically on 400A and up services, I see CTs used and disconnects are needed.
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IME, PV is rarely interconnected ahead of the revenue meter in commercial systems and almost never in residential systems, so pulling the revenue meter nearly always shuts down the PV, but every jurisdiction I work in requires a bladed disco (lockable, labeled, with a visible break) for all PV interconnections.
 
ggunn said:
IME, PV is rarely interconnected ahead of the revenue meter in commercial systems and almost never in residential systems, so pulling the revenue meter nearly always shuts down the PV, but every jurisdiction I work in requires a bladed disco (lockable, labeled, with a visible break) for all PV interconnections.
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Except that above certain amperages pulling the meter doesn't disconnect power, PV or no PV. That was the detail being discussed.
 
jaggedben said:
Except that above certain amperages pulling the meter doesn't disconnect power, PV or no PV. That was the detail being discussed.
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I guess you are talking about CT meters, where the meter only reads the CT values, not the current itself. Irrespective of that, every PV system I have designed has had a bladed disco between the inverter(s) and the interconnection because all the jurisdictions I work in require it.
 
ggunn said:
I guess you are talking about CT meters, where the meter only reads the CT values, not the current itself. Irrespective of that, every PV system I have designed has had a bladed disco between the inverter(s) and the interconnection because all the jurisdictions I work in require it.
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It's totally up to where you are working. If you were working on residential PV in CA in PG&E territory then you would not need to use a PV disconnect.
 
pv_n00b said:
It's totally up to where you are working. If you were working on residential PV in CA in PG&E territory then you would not need to use a PV disconnect.
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No disagreement there. The requirement for a bladed disco is one of the few universal requirements for me, but I know it varies elsewhere. For other things in the many jurisdictions we work in we are building a spreadsheet that lists the requirements that are different for different AHJs, i.e., fire code enforced (yes or no), trim and rack over PVC vents OK (yes or no), line side connection considered a service entrance (yes or no), PV meter required (yes or no), if PV meter required, placement relative to disco (ahead or behind), modules OK on roof surface facing the street (yes or no)... The list goes on. And then there are utility AHJs and municipality AHJs which may or may not be one and the same.
 
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ggunn said:
No disagreement there. The requirement for a bladed disco is one of the few universal requirements for me, but I know it varies elsewhere. For other things in the many jurisdictions we work in we are building a spreadsheet that lists the requirements that are different for different AHJs, i.e., fire code enforced (yes or no), trim and rack over PVC vents OK (yes or no), line side connection considered a service entrance (yes or no), PV meter required (yes or no), if PV meter required, placement relative to disco (ahead or behind), modules OK on roof surface facing the street (yes or no)... The list goes on. And then there are utility AHJs and municipality AHJs which may or may not be one and the same.
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Yup, this is one of the big soft cost drivers in the US versus say Germany. In Germany, there is one utility for the whole country and one set of codes and standards. In the US there are thousands of utilities all with their own flavor of requirements and thousands of more AHJs with variable requirements loosely based on a national electrical and building code.

But try to establish a national system of codes and standards and the howl and cry of 10,000 local building department Barrons in the castles of local power they have built will rise up and crush any attempt.
 
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