A quick code concern

The question is in Arizona is it legal (up to code) to run both AC and DC lines through the same piece of conduit?
I built a new generator house and need to run the lines from outside passed my solar panels and into my utility room. As I pass my solar panels I want to tie in to my inch and a half conduit. Instead of running a whole new line of conduit does anybody see any issues with this.
I built a new generator house and need to run the lines from outside passed my solar panels and into my utility room. As I pass my solar panels I want to tie in to my inch and a half conduit. Instead of running a whole new line of conduit does anybody see any issues with this.
100% Off-grid in the White Mountains of Arizona. 36 Kyocera 265w mounted on four DPW 9 module pole top mounts, midnite solar combiners, breakers, & lightning arresters, 1 midnight solar classic 150, & 3 classic 150 lights, 3 x 1574 AH GB Industries forklift batteries total of 4722 AH @24v. Feeding a Outback power systems FW500 with 2 x VFX 3624, with the x240. 2 Honda EU3000is gensets with the 240 combiner and control box running LP, and 1 Honda EU2000is Gas.
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
Comments
Seperate conduit runs.
DC side requires labelling
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
Although there is no general restriction for "AC and DC" to be in the same raceway, NEC 690.4(B) requires conductors of photovoltaic source and output circuits to not be in the same raceway as conductors of "other systems". However I would personally have no problem with this if it didnt need to be "up to code".
You should have a problem with it because DC circuits use seperate over current protection from AC over current protection.
The concept is that solar does not shut off, so it uses a combiner with overcurrent protection devices. AC Line side does not operate in the same nature as DC current.
The only way to avoid all these circumstances" not so complicated problems", is if you want one conduit run, design/build for micro inverters, if it is not off grid, or hybrid. Micro inverters simplify everything, and don't even require an ac disconnect.
In the event an electrical fire occurs/happens combining in one channel between the 2 parts of 1 system the voltage can well exceed 600V potential. That is the purpose of the separation, because of voltage, not whether or not the over current reacts to amperage. Most breakers can operate well above a 600V threshhold.
Well first to clarify, What I meant was I would have no trouble doing so at my own house, and I dont see any safety issue with folks doing this where they build and maintain their own electrical systems and they dont need NEC compliance. When I am working in a professional capacity, I strictly follow codes regardless of whether it is getting inspected or not.....
I do not agree with your assessment of the reason for this requirement. I dont see a voltage issue as long as all conductors are rated for the highest voltage encountered, and pretty much all conductors are 600v rated these days. Now if you had a 1000v Pv system supplying 1 KV PV wire mixed with some 600V THHN then of course that would not be kosher. I guess it is theoretically possible for positive and negative of two different strings to fault resulting in a "string" of 1200V, but that seems pretty far fetched and I just dont think the CMP was thinking of that scenario and if they were they should have taken "PV output circuit" out of the requirement.
Regarding current I see no problem here either as it is common to have a feeder protected at hundreds of amps to be in the same raceway as a 20 amp branch circuit.
I assume the reason for the requirement is because the PV conductors will essentially never be dead (until the new rapid shutdown becomes common) and its a safety issue for people working on the system and thinking they "turned the breakers off". But who really knows, the CMP's frequently come up with code requirements that dont follow logic and reason
This is in regards to how inverters operate.
Hypothetically the DC end you can have a string operating at 580V
AC end will operate at 240V
Combining one end from the other exceeds the 600V maximum.
There are 2 different cycles and types of linear, and non linear electricity, which can pose conductors to melt long before over current reacts and shuts down one end or the other of inverter. Even if EGC is installed in error such as teh bakersfield macy's fire that was in solar pro magazine, and that issue was a DC side only issue, and EGC/GEC bonding issues that weren't compliant with code.
This is why "string" inverters are required to have a GEC, which in the case of micro its just EGC out, because micro's are both AFCI, and GFCI protected for EGC out, there is no GEC conductor or bare copper past the point of micro.
How its been explained to me by the engineers.There are 2 different streams of voltage occuring at different rates. Putting both sets of conductor in 1 run does pose the potential for Arch. Or atleast that is how the engineers have explained it to me in laymens terms.
As of now only micro inverters meet the requirements for NEC rapid shut down and that is probably because the DC run is under 3', and there are 2 forms of protection at the point of inverter. I don't at any time see this actually happening with string inverters on a commercial, or residential level, mostly because of both DC and AC conductor lengths that are required, and the means of combining.
According to how string inverters do operate under frequency conditions requiring frequency to generate power for grid, string inverters should and do meet rapid shut down. I believe there is just to much complication with code language why string inverters havent been identified as the switching mechanism for rapid shut down. If that were the case.
Yes than I would agree with you 100% that both dc and AC side could share a common conduit/channel.
DC side of system has the potential for Arching as a linear load. Voltage can literally jump onto non linear voltage, coming in from the grid
The connection of this topic is that it was a point of failure on the DC end side of the system which caused the fire. If by chance both DC and AC sides were to be within the same race way then the ac side as well would of been prone to that fire bypassing the GFP of inverter. Separation is to prevent the "cross contamination" of the 2 parts of the system in case one part or both parts of the system fail. In either regards to lack of understanding code, incompetence of installation in the case of the bakersfield fire (which we come to find out really only required a GEC conductor within the raceway), and for what ever reason why it did not happen, well that is definitely an installer error. Code is made to have fail safes, checks and balances as additional preventative measures so when, or (if) part of a system is bound to fail regardless of competence of installation, the additional safe guards allow for shut down at one, or both parts of either DC or AC side of system, to prevent additional problems (such as fires spreading to other locations such as inverter pad/switch gear rooms, etc).
We are both in agreement. I believe it is more so how jurisdictions interpret the language.
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
We weren't talking about termination,
This was about seperate raceways, grounding, and how it affects the solar system.
If by chance your system is under 10amps on both DC and AC side, you could disregard seperate chase way/conduits as NEC doesn't recognize over current protection under 10amps of current.
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
conduit you cannot open , a raceway you can
I was sure you could have both ac and dc in the same raceway......but not conduit
It has nothing to do with AC vs DC. Here is the applicable code section:
NEC 690.4(B) Conductors of different systems. Photovoltaic source circuits and photovoltaic output circuits shall not be contained in the same raceway, cable tray, cable, outlet box, junction box, or similar fitting as feeders or branch circuits of other systems, unless the conductors of the different systems are separated by a partition or are connected together.
The reason for the separation is NOT that the two systems have different OverCurrent Protection Devices (OCPD) nor that the voltages can add because they are out of phase and might arc nor that they come from different sources.
The NEC has several major provisions about not sharing:
1. Power limited circuitry (Class 2 and Class 3) cannot share a raceway with power wiring probably because a short to the Power Limited circuit could cause severe problems before any OCPD tripped.
2. Service wires (effectively having no OCPD since POCO sizes their primary side OCPD to protect their wiring and system integrity, not the secondary wiring (you) cannot be combined with building wiring with OCPD just because the service wires are inherently dangerous and are not even allowed inside the building except for limited distances. Any fault to feeder or branch wiring could cause a fire in the branch wiring or equipment.
3. Solar PV input and output circuits, because the Code says so. Period. That is all you need to understand.
Sharing a conduit and sharing a raceway are both prohibited by 3.
You can run them through the same weatherproof entrance into a building as long as that entry is not part of a raceway system.
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
http://members.sti.net/offgridsolar/
E-mail offgridso[email protected]
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
Normal wiring separation, good insulation, and wiring practices. The gear is UL listed right and you are using it per Midnite docs?
People combine low voltage solar in/out in one conduit all the time like the Outback and Schneider manuals show.
On the XW system with a 400 vdc solar charger everything is the way I would want it, and it is UL listed
http://members.sti.net/offgridsolar/
E-mail [email protected]
I'm not really sure how contorted the logic is, but this came up in another thread about parallel cables.
Generally speaking, parallel cables are NOT permitted. (NEC does allow parallel cables, in some narrow circumstances). Inetdog pointed out that if you have circuit breakers in each of the 'parallel' cables, then technically they are not parallel, because they are connected to a device (the circuit breaker), not to each other.
--vtMaps
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
Follow our journey at
https://www.facebook.com/ShawnpHarvey
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
Not sure who is telling you that but it makes no sense. Absolutely no restriction on putting conductors of different ampacity in the same raceway
The closest solid provision in the NEC is that service wires (which have NO overcurrent protection to speak of) must not share a raceway with protected wires. The idea is that you do not want any possibility of the unlimited service wires getting shorted to the protected wires.