Hello all, I plan to install a 600 watt, 60v 10 amp solar array permanently to my house (roof), running to a MPP all in one 12v. Seeing if I need to set up a RSS for it? They are 3- 200 watt 12v panels. Would just a manual disconnect located outside be good enough?
Rapid system shutdown for 600 watt system
- Thread starter Colemoney
- Start date
hankcurt
Solar Enthusiast
This is a question that can probably only be answered by your local authority having jurisdiction (AHJ) at your permits and inspections office.
US National Electric Code prior to 2014 required shutdown within 10 feet of the array outside the building. From 2017 on, it requires shutdown within 1 foot of the panel array.
US National Electric Code prior to 2014 required shutdown within 10 feet of the array outside the building. From 2017 on, it requires shutdown within 1 foot of the panel array.
Depending on where you live, you may need a structural engineer to certify your roof in a sealed report with permit submission. I seriously doubt any AHJ will approve a MPP All In One. You will also need to make sure the MPPT has ground and arc fault protection as well as Rapid Shutdown system like a Tigo.
Do you think a manual disconnect located within 1 ft would be qualify? Im trying to avoid the cost and install of an automated version.
hankcurt
Solar Enthusiast
It really depends on how your code inspector interprets the code and which code version you are under.
The easiest way to simplify things is to make a ground mount. Not being on the roof of a dwelling relaxes the requirements.
The easiest way to simplify things is to make a ground mount. Not being on the roof of a dwelling relaxes the requirements.
Sounds good, ill look at going that direction.
T-486 Ashepoo
New Member
Can you use a ground mount or mount on a shed? I didn't think 12v/24v needed RSD.
hankcurt
Solar Enthusiast
@T-486 Ashepoo , you bring up a good point. I read the first sentence of the original post and assumed that he was wiring the panels in a string that would put out 60v at 10 amps. The rapid shutdown requirements from NEC 2017 and 2020 require that the voltage outside the 1 foot boundary be reduced to less than 30 volts within 30 seconds of tripping the rapid shutdown.
If the panel output voltage is kept under 30 volts at all times, then there should be no need for rapid shutdown.
I guess I'm unclear on how @Colemoney intends to wire the panels if he has three 200watt 12volt panels. In series, as I interpret it, he would need rapid shutdown because the voltage would be above 30 volts. You also have to consider that this applies to open circuit voltage, not just normal operating voltage.
If the panel output voltage is kept under 30 volts at all times, then there should be no need for rapid shutdown.
I guess I'm unclear on how @Colemoney intends to wire the panels if he has three 200watt 12volt panels. In series, as I interpret it, he would need rapid shutdown because the voltage would be above 30 volts. You also have to consider that this applies to open circuit voltage, not just normal operating voltage.
You assumed correctly. Sounds like then my options then would run them around 20 volts and 30 amps...ill consider the ground mount at that point. Thanks all for the input!
PV system circuits installed on or in buildings shall include a rapid shutdown function that controls specific conductors in accordance with 690.12(1) through (5) as follows.
so technically, anything more than a single panel requires RSD. i wouldn't bother for your system. so long as you aren't impeding access to your roof, I don't think you're going to have any issues. however, you will need to remove the panels if you have it inspected or sell.
fortunately for you, you do not need to comply with 690.11 AFCI requirements as you have a Voc < 80v
- More than 5′ inside a building, or more than 10’ from a PV array
- Controlled conductors shall be limited to not more than 30V and 240 volt-amperes within 10 seconds of rapid shutdown initiation
- Voltage and power shall be measured between any two conductors and between any conductor and ground.
- The rapid shutdown initiation methods shall be labeled in accordance with 690.56(B).
- Equipment that performs the rapid shutdown shall be listed and identified.
so technically, anything more than a single panel requires RSD. i wouldn't bother for your system. so long as you aren't impeding access to your roof, I don't think you're going to have any issues. however, you will need to remove the panels if you have it inspected or sell.
fortunately for you, you do not need to comply with 690.11 AFCI requirements as you have a Voc < 80v
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no, it does not because the total Voc for the series is more than 30v
Thank you for the info
