Rapid shut down

[SAP]

We have been installing solar edge inverters with optimizers for about a year in a half. we are on the 2011 nec but not for long. From my understanding solaredge is rapid shut down compliant. Come 2014, I should not be affected has long has I keep with solar edge, the 10' and 5' are only for inverters that do not have rapid shut down. I can mount my solar edge inverter next to my service, w/ my array 30' away from my inverter and not have to add any extra devices on roof. I'm I on the right track thank you

 

[ggunn]

We have been installing solar edge inverters with optimizers for about a year in a half. we are on the 2011 nec but not for long. From my understanding solaredge is rapid shut down compliant. Come 2014, I should not be affected has long has I keep with solar edge, the 10' and 5' are only for inverters that do not have rapid shut down. I can mount my solar edge inverter next to my service, w/ my array 30' away from my inverter and not have to add any extra devices on roof. I'm I on the right track thank you

Most SolarEdge inverters you can buy these days are RS compliant, but if the one you get has been in a warehouse for a while you may have to install a resistor kit between the + and - DC terminals and upgrade the firmware.

 

[Carultch]

We have been installing solar edge inverters with optimizers for about a year in a half. we are on the 2011 nec but not for long. From my understanding solaredge is rapid shut down compliant. Come 2014, I should not be affected has long has I keep with solar edge, the 10' and 5' are only for inverters that do not have rapid shut down. I can mount my solar edge inverter next to my service, w/ my array 30' away from my inverter and not have to add any extra devices on roof. I'm I on the right track thank you

It's not about the "inverter having rapid shutdown", it is about the SYSTEM having rapid shutdown.

SolarEdge has module-level (or module-pair level if you design it that way) rapid shutdown by design, where the optimizers default to 1 V / unit when the circuit is open. The power and higher voltage is stopped at the optimizer, and the circuit from the array to inverter is <30Vdc. The inverter can be anywhere, not just within the 5' inside / 10' general limit.

Other conventional string inverters will by default keep the DC side energized at full open circuit voltage, even when off. So you'd need a DC disconnecting means like a contactor or shunt trip switch somewhere in the system to cut the DC feeder off from the array.

 

[ggunn]

It's not about the "inverter having rapid shutdown", it is about the SYSTEM having rapid shutdown.

Yes, but some inverters help with RSD and some don't. We have discussed SolarEdge; some other inverters supply DC to a contactor box on the roof, some just provide a relay to signal AC power down, and others don't do anything.

 

[Carultch]

Yes, but some inverters help with RSD and some don't. We have discussed SolarEdge; some other inverters supply DC to a contactor box on the roof, some just provide a relay to signal AC power down, and others don't do anything.

True. For the ones that don't, you need to design the DC system to include additional components to comply. For the ones that do, you need to consult the manual for details.

 

[JasonC]

Initiating RS

Initiating RS

You may want to watch out for the verbiage, as the listed initiating procedure needs to be readily accessible. For Solaredge that is the turn job or little red switch it is not the AC disconnect. Our AHJ's required the inverters to be placed outside. Also be careful when showing Arc fault compliance add they don't always pass initially.

 

[pv_n00b]

You may want to watch out for the verbiage, as the listed initiating procedure needs to be readily accessible. For Solaredge that is the turn job or little red switch it is not the AC disconnect. Our AHJ's required the inverters to be placed outside. Also be careful when showing Arc fault compliance add they don't always pass initially.

The latest SolarEdge RSS does away with the need to open the DC disconnect. Now it operates on loss of utility AC.

 

[jaggedben]

You may want to watch out for the verbiage, as the listed initiating procedure needs to be readily accessible. For Solaredge that is the turn job or little red switch it is not the AC disconnect. Our AHJ's required the inverters to be placed outside. Also be careful when showing Arc fault compliance add they don't always pass initially.

Readily accessible is a 2017 requirement, if I recall correctly. The OP won't be on that code for three years.

Also readily accessible does not require outside under the NEC. That might be a local requirement.

 

[Carultch]

Readily accessible is a 2017 requirement, if I recall correctly. The OP won't be on that code for three years.

Also readily accessible does not require outside under the NEC. That might be a local requirement.

The 2014 rule on where the initiation point has to be is so vague, you could theoretically have it on your neighbor's house and still comply with the wording of the NEC. I'm exaggerating, but a practical case where you might see something that might feel just as wrong, is an array on a detached barn and interconnected at a main house with the initiation point on the main house.

 

[jaggedben]

The 2014 rule on where the initiation point has to be is so vague, you could theoretically have it on your neighbor's house and still comply with the wording of the NEC. I'm exaggerating, but a practical case where you might see something that might feel just as wrong, is an array on a detached barn and interconnected at a main house with the initiation point on the main house.

Some jurisdictions around here have been requiring a DC disconnect on the roof for years and I wonder why we should change methods now that we're on the 2014 code.

 

[ggunn]

The 2014 rule on where the initiation point has to be is so vague, you could theoretically have it on your neighbor's house and still comply with the wording of the NEC. I'm exaggerating, but a practical case where you might see something that might feel just as wrong, is an array on a detached barn and interconnected at a main house with the initiation point on the main house.

What is an "initiation point"?

 

[shortcircuit2]

In 2017 its called an "Initiation Device" ...and for 1 & 2 family dwellings it must be ready accessible and outside the building. But most of you won't deal with this for some time.

This is found in the NEW 690.12(C)...now, there is some language in there that may start some conversation as a "grey area"...for example, the device"off" position shall indicate that the rapid shutdown function has been initiated...so what will be the indicator? An audible sound? A visual indicating light? Or just a label next to the off position of the switch...saying Rapid Shutdown Function?

I am really focusing in on 2017 now, because we here in Massachusetts are under the 2017 Code.

 

[GoldDigger]

What is an "initiation point"?

The point in the circuit and the world from which you can initiate a rapid shutdown.

Sent from my XT1585 using Tapatalk

 

[SolarPro]

This is found in the NEW 690.12(C)...now, there is some language in there that may start some conversation as a "grey area"...for example, the device"off" position shall indicate that the rapid shutdown function has been initiated...so what will be the indicator?

The text that says "OFF" is the indicator.

While the product safety standard (for 2017 rapid shutdown) is very much a work in progress, I expect the STP to use loss of AC power as the trigger for rapid shutdown initiation. If that is the case, first responders just show up on site and do what they would normally do and any on-site dc PV system circuits will shutdown along with the ac circuits. In other words, with rapid shutdown on loss of ac power, the main breaker can serve as the initiation device. Easy peasy.

 

[Carultch]

The text that says "OFF" is the indicator.

While the product safety standard (for 2017 rapid shutdown) is very much a work in progress, I expect the STP to use loss of AC power as the trigger for rapid shutdown initiation. If that is the case, first responders just show up on site and do what they would normally do and any on-site dc PV system circuits will shutdown along with the ac circuits. In other words, with rapid shutdown on loss of ac power, the main breaker can serve as the initiation device. Easy peasy.

It would work in most grid-tied systems, except that wouldn't work in a system that has battery backup. Such a system would inherently require an additional initiation device, as it is designed to remain ON when the grid power shuts off.

 

[pv_n00b]

The 2014 rule on where the initiation point has to be is so vague, you could theoretically have it on your neighbor's house and still comply with the wording of the NEC. I'm exaggerating, but a practical case where you might see something that might feel just as wrong, is an array on a detached barn and interconnected at a main house with the initiation point on the main house.

I have seen interesting examples of this, like a DC disconnect mounted on the outside second story wall of a house. No way to get to it without a ladder. There is a difference between just checking off a box in the NEC and installing a usable safety system. Using the vagueness of the NEC to justify poor designs is an age old problem.

Some jurisdictions around here have been requiring a DC disconnect on the roof for years and I wonder why we should change methods now that we're on the 2014 code.

Well, maybe because in the past we did not have the equipment to allow remote isolation of the array, and a manual DC disconnect was the best we had to work with, but now we do have better ways of doing it so let’s use them. I know it’s a crazy idea but let’s give it a try. :blink:

 

[shortcircuit2]

The text that says "OFF" is the indicator.

While the product safety standard (for 2017 rapid shutdown) is very much a work in progress, I expect the STP to use loss of AC power as the trigger for rapid shutdown initiation. If that is the case, first responders just show up on site and do what they would normally do and any on-site dc PV system circuits will shutdown along with the ac circuits. In other words, with rapid shutdown on loss of ac power, the main breaker can serve as the initiation device. Easy peasy.

OK on your OFF interpretation. But OFF is OFF, and it has always indicated that what a switch controls is off...why do they need to put that in the language of the Code. This OFF rule will restrict the use of shunt controlled breakers as a Rapid Shutdown Function.

Anyway, its not that easypeasy around here, because most main breakers are inside dwellings in my area. But the Utility company in my area requires a lockable visual make/break disconnect on the outside of the dwelling...this may be used for that "Initiation Device".

Another issue with the Solaredge Inverter (2017 NEC)... is that they don't get to safe voltage in 30 seconds on AC Disconnect shutdown. So we will see the SE inverters all going outside until SE gets them to meet the 2017 30/30 rule. Micro-inverters may pick up some work here where owners don't want the inverter outside for aesthetics.

 

[SolarPro]

Another issue with the Solaredge Inverter (2017 NEC)... is that they don't get to safe voltage in 30 seconds on AC Disconnect shutdown. So we will see the SE inverters all going outside until SE gets them to meet the 2017 30/30 rule. Micro-inverters may pick up some work here where owners don't want the inverter outside for aesthetics.

That is true of the previous generation of SolarEdge inverters. The most recent generation initiates rapid shutdown upon loss of AC power.

If your main breaker is inside, then, yes, the utility-mandated ac disco is the logical initiation device. That's the beauty of the initiating rapid shutdown on loss of ac power. It doesn't matter what device you use, but if you shut down ac power to the facility, any dc PV circuits follow suit. It just keeps everything simple.

(The STP process won't be simple, but complying with rapid shutdown should be. Otherwise, what's the point.)

 

[pv_n00b]

The text that says "OFF" is the indicator.

While the product safety standard (for 2017 rapid shutdown) is very much a work in progress, I expect the STP to use loss of AC power as the trigger for rapid shutdown initiation. If that is the case, first responders just show up on site and do what they would normally do and any on-site dc PV system circuits will shutdown along with the ac circuits. In other words, with rapid shutdown on loss of ac power, the main breaker can serve as the initiation device. Easy peasy.

Loss of AC will have to be only one of the options to initiate RS since that by itself would render any backup PV system unless. Most systems will use loss of AC, but most of the rest using a switch of some type. There are a lot of those SMA inverters with the backup power outlet that will need to stay running on loss of AC.

 

[jaggedben]

Loss of AC will have to be only one of the options to initiate RS since that by itself would render any backup PV system unless. Most systems will use loss of AC, but most of the rest using a switch of some type. There are a lot of those SMA inverters with the backup power outlet that will need to stay running on loss of AC.

The SMA back up power outlets require manual operation to turn on anyway, so it's not inconceivable to have a Rapid Shutdown device that can still operate on loss of AC, but has a manual override of some sort. FWIW, SMA has a Rapid Shutdown product that does not operate on loss of AC power. But it has a controller component which seems like it could be easily re-engineered to trigger on such loss and also function manually.