without conduit

Status
Not open for further replies.
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I have junction box on roof where wires transition to PV wire. I have 3 strings so six PV wires. One of the string is right next to junction box. The other two are on opposite ends on roof. Does NEC 2014 require to have conduit on roof with PV wire for other two strings from junction box or can PV wire run without conduit to other strings on roof?

Sent from my SM-G935U using Tapatalk
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
hhsting said:
I have junction box on roof where wires transition to PV wire. I have 3 strings so six PV wires. One of the string is right next to junction box. The other two are on opposite ends on roof. Does NEC 2014 require to have conduit on roof with PV wire for other two strings from junction box or can PV wire run without conduit to other strings on roof?

Sent from my SM-G935U using Tapatalk
Click to expand...
I did really appreciate your input and thank you in advance. I am not trying to troll and please forgive my ignorance.

Sent from my SM-G935U using Tapatalk
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I don't think NEC strictly requires it but conduit (EMT) is typical practice when running between arrays. Another option sometimes chosen for larger systems is cable tray. Sometimes you can use a strut channel or other racking that's there. I have looked to the rules for supporting USE-2 although they may not strictly apply.

Laying PV wire directly on the roof is not okay, I think that violates workmanship if nothing else. :happyno: Probably temperature derating too.
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Please see attached sketch. Roof is flat apartment complex. It shows roof layout string array #1, string array #2, string array #3 and Junction box. Under the roof layout is single line diagram that shows junction box. To junction box left from electric room their is THWN-2 in EMT up to J box. J box transitions to PV wire go to array and strings #1, #2, #3 with one EGC.

The question is going from junction box to array string #3 is long distance PV wire one positive and one negative does it need to be in conduit or can be on roof without conduit? And what about EGC can it be separate or has to be in conduit? Which code section address all this their is no PV wire article.
fba44dd21d7839cbabdc451b913272ec.jpg


Sent from my SM-G935U using Tapatalk
 
Last edited:
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I think I already answered the question.

Either the installer uses a professional method to protect the PV wire from damage of they are violating 110.3(A), or 110.12, or something else like that.
 
Last edited:
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Their is also NEC 2014 Article 690.31. 2014 Article 690.31(A) says readily accessible has to be in raceway. On roof is considered readily accessible? Also 2014 Article 690.31(C) single conductor would string #3 one postive and one negative single conductor but that too has exception NEC 2014 Article 690.31(C) in raceway. Its just all confusing.

Sent from my SM-G935U using Tapatalk
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The roof is not readily accessible if it requires a portable ladder. It is readily accessible if there's a staircase going to it. To give a couple examples.

'Readily accessible' is defined in Article 100.
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Right but one your on roof these cables would be readily accessible. So raceway would be needed regardless?

Sent from my SM-G935U using Tapatalk
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Its not academic well its on engineering plans to be constructed. As a plans reviewer you see all sort of weird situations on plans ofcourse before they are approved. Came across engineering plans that showed whats shown on sketch post #4 PV wire without conduit and junction box roof layout without any indication of how PV wires are routed or in what and long distance to string array #3. Its just a thought insulation may get damaged without conduit or sharp object may pentrate, animal may chew insulation, harsh envirnment etc etc all situation that is danger may cause electrocuation may cause fault thats all but I am not too familiar if this would apply to PV wires or not neither too familiar with 690 keeps on changing. Was wondering if their is anyway to prevent this in 2014 code or PV wires can be on roof without conduit. Cant just recommend to the engineer who designed wont listen so lets go the NEC 2014 enforcement way.
 
Last edited:
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It seems like you're speculating. I'm doubtful that the lack of detail on the plans means that they have no intention of protecting or supporting the PV wire between arrays. Did you actually ask them?
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
jaggedben said:
It seems like you're speculating. I'm doubtful that the lack of detail on the plans means that they have no intention of protecting or supporting the PV wire between arrays. Did you actually ask them?
Click to expand...
Ues ofcourse but they said it would be roof without conduit exactly whats shown on plans. I argued not the best idea any conductor without conduit but without whats in code its not going anywhere.
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Nec 2014 Article 690.43(F) says EGC has to be within same cable or raceway. So does this mean their needs to be separate EGC for each string from J box? I have three strings and each PV wire would have EGC with it but there are no conduits provided?

Sent from my SM-G935U using Tapatalk
 
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
hhsting said:
Ues ofcourse but they said it would be roof without conduit exactly whats shown on plans. I argued not the best idea any conductor without conduit but without whats in code its not going anywhere.
Click to expand...

I cannot imagine that the plan would be for the conductors to just be strung across and laid directly on the roof without a raceway. If they are run under another subarray secured to the underside of it, running without conduit would be OK, but laid directly on the roof would never pass inspection in any jurisdiction I deal with. Even in conduit you wouldn't want to do that; the heat adder to the derate would be substantial even in the 2017 NEC.
 
P

paulengr

Senior Member
There is a part of the 2017 Code for service conductors mounted over roofing dealing with spacing off the roof including covering if any since PV is essentially a service.


Sent from my iPhone using Tapatalk
 
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
hhsting said:
Nec 2014 Article 690.43(F) says EGC has to be within same cable or raceway. So does this mean their needs to be separate EGC for each string from J box? I have three strings and each PV wire would have EGC with it but there are no conduits provided?

Sent from my SM-G935U using Tapatalk
Click to expand...
no one answered above got lost

Sent from my SM-G935U using Tapatalk
 
Status
Not open for further replies.
Top