690.12 is a joke for firefighters I know.
Do TIGOs actually work?
- Thread starter Phil Timmons
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jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Perhaps, but that's what 690.12 is about.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
They may or may not be unfused. Actually 690 does require a disconnect or certain wiring methods where they enter a building, so they are treated similarly in that respect. But that isn't what is at stake with Rapid Shutdown.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Because they are not service conductors or similar in any way?
Carultch
Senior Member
- Location
- Massachusetts
Conductors that are between a fused disconnect (or breaker) and the service point are "not similar" to service conductors? I don't agree.
I see that they have a lot in common with service conductors, and so any rule governing service conductors in general, would also apply to them. Not the 310.15(B)(7) rules that depend on load diversity specific to dwelling unit loads, since it's a continuous load without any load diversity. But for every other aspect, they have a lot in common with service conductors.
wwhitney
Senior Member
- Location
- Berkeley, CA
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- Retired
Looking at post #38, the discussion lately has not been about those conductors, but about conductors subject to 690.12 "Rapid Shutdown."
Cheers, Wayne
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
He was talking about DC conductors from a PV array. Of course unprotected conductors between a PV AC disco and a supply side POI should be treated similarly as are conductors ahead of the main service disconnect.
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I would wager Electricians (that dont do solar) have been trained in and worked under the NEC or the CEC for a long time put the power circuits they work on into 3 main categories 1) Conductors that receive their protection at the load side like service and tap conductors. 2) feeders that start from a OCPD and 3) Lastly branch circuits.
Then when you get into doing solar we find the code has defined a few DC circuits, all in 690 and there are at least 3 types 'Photovoltaic Output Circuit', 'Photovoltaic Source Circuit', ' Inverter Input Circuit.' And some can overlap.
Then when you get into doing solar we find the code has defined a few DC circuits, all in 690 and there are at least 3 types 'Photovoltaic Output Circuit', 'Photovoltaic Source Circuit', ' Inverter Input Circuit.' And some can overlap.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
If you are reading the NEC to determine what needs to be done for PV systems, sometimes you have to stand on your head. 
solarken
NABCEP PVIP
- Location
- Hudson, OH, USA
- Occupation
- Solar Design and Installation Professional
What exact model of TS4 is installed in this system, As pv_n00b said, "Maybe you got a batch of TS4-A-Ms by mistake? It's the only one they have without RSD built in.
Yes conductors that get their protection at the load side, you have overload, ground fault and short circuit types of protection, usually provided by a breaker or fuse. Or with motors overloads and fuse/breaker.
I get the PV available fault current is super small and conductors are sized to carry that.
I am still thinking DC solar wires are like service conductors, IF they get protected at load end.
...
Let me pose a imaginary 'what if' here for just a second..
Say just say a utility provides a 60 amp 600V DC service to a large building, lets say overhead.
Yes DC guys and gals...
Or something like what a PV system would be from panels to inverter 690.12 but outside array and not solar using NEC 230 rules for a DC service...?
Now the drop is on one side of the building I pipe DC service conductors 600V in EMT say 300 feet across a commercial roof, 40 feet down the side LB into a service disconnect, from there its a feeder.
As per 230.6 the DC service conductors 300 feet across roof are still outside the building.
Is that not the same as a PV system with no rapid shutdown?
If a firefighter had to cut that roof the DC service would be still hot.
What is so special about a PV system that it needs 690.12? A rapid shutdown?
Is it that the conductors enter the building thru the roof?
Thank you all for your time and enlightening me to something new.
I get the PV available fault current is super small and conductors are sized to carry that.
I am still thinking DC solar wires are like service conductors, IF they get protected at load end.
...
Let me pose a imaginary 'what if' here for just a second..
Say just say a utility provides a 60 amp 600V DC service to a large building, lets say overhead.
Yes DC guys and gals...
Or something like what a PV system would be from panels to inverter 690.12 but outside array and not solar using NEC 230 rules for a DC service...?
Now the drop is on one side of the building I pipe DC service conductors 600V in EMT say 300 feet across a commercial roof, 40 feet down the side LB into a service disconnect, from there its a feeder.
As per 230.6 the DC service conductors 300 feet across roof are still outside the building.
Is that not the same as a PV system with no rapid shutdown?
If a firefighter had to cut that roof the DC service would be still hot.
What is so special about a PV system that it needs 690.12? A rapid shutdown?
Is it that the conductors enter the building thru the roof?
Thank you all for your time and enlightening me to something new.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I think the difference is that whereas a service enters the building a one point where it can be shut off, DC PV conductors of different circuits may run through hundreds or thousands of square feet of PV arrays on the roof surface. A single line 300ft across a commercial roof doesn’t really come close to describing the possible number and breadth of DC PV conductors on such a building, or the impact on firefighting operations if arrays cover virtually all the open space on a roof. So no, it's not the same. 690.12 essentially requires that, practically speaking, firefighters can still make all that area substantially safe from very large electrical hazards by throwing a few handles.
Phil Timmons
Senior Member
- Location
- DFW
- Occupation
- Depends on the pay and the day
Thanks for bringing this back on task and target.
Same to pv_n00b.
Quick Answer . . . (actually my favorite answer for most things) . . . . I DO NOT KNOW.
Having the roof crew(s) check for that now. Actually I did not know that TIGO even did one without RSD.
You are both correct -- could be a shipment or order error, and the roof crew would not notice.
Per the prints and orders (that I have tracked) ALL of what we have installed are the Full Featured TIGOs -- TS4-A-O
Tigo TS4-A-O
Optimization is a Flex MLPE function available as an integrated modular junction box base (TS4-O) or as an add-on unit (TS4-A-O). Design using unequal string lengths, mixed orientations, or areas of mismatch. Install in shaded areas with a reduced setback ratio. In addition to optimization, the...
www.tigoenergy.com
(for folks tracking along -- these are what we are talking about) -- https://www.tigoenergy.com/ts4
One of the ongoing issues with the DC conductors and PV modules in the array is that the power can't be easily disconnected. To de-energise the conductors you need to isolate the modules and to de-energise the modules you have to turn off the sun. Neither of these is all that easy to do. RSD provides a way to de-energize the DC conductors but not the modules so it gets us halfway.
To de-energise the residential service conductors firefighters can just cut the service drop if they need to go that far.
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