Over head pv wire

[Good guy]

I have a job I have to do plans have been approved. Only thing is I’ve never ran DC conductors over head and it’s over 600 volts. Plans say 80’ conduit run between buildings looks like it’s a commercial driveway I will be going across. plans also say weather head on both roofs. Without going down a wall like a service with ridged conduit How would I secure my conduit. Does anybody have any experience with this thanks in advance

 

[electrofelon]

I have a job I have to do plans have been approved. Only thing is I’ve never ran DC conductors over head and it’s over 600 volts. Plans say 80’ conduit run between buildings looks like it’s a commercial driveway I will be going across. plans also say weather head on both roofs. Without going down a wall like a service with ridged conduit How would I secure my conduit. Does anybody have any experience with this thanks in advance

I'm not entirely clear. Are they saying/expecting conduit be used for the aerial portion? Or could that part be messenger supported?

 

[Good guy]

I'm not entirely clear. Are they saying/expecting conduit be used for the aerial portion? Or could that part be messenger supported?

its messager supported with a weather head on each side

 

[electrofelon]

So what is the question? Is it what to use for the aerial cable?

 

[Good guy]

So what is the question? Is it what to use for the aerial cable?

Yes do they sell 1000 volt Ariel cable and how would I attach the riser I know about the roof support kit using 3/4 ridged conduit

 

[electrofelon]

Yes do they sell 1000 volt Ariel cable and how would I attach the riser I know about the roof support kit using 3/4 ridged conduit

I am not aware of any off the shelf 1kv rated cable. I have ordered custom wire combinations and had them plexed, so you could see about getting some 2kv PV wire plexed with a messenger. Although for only 80 feet I would probably just make it up myself.

Not clear on the exact layout, but I would think if they are flat roofs you could just stick a weather head out a foot and transition to the aerial.

 

[tortuga]

Could you just set a cross arm and run some Turkey (6 ASCR) like a lineman would for 7.2?

 

[BillK-AZ]

Proper tensioning of the messenger cable vs temperature is important. Most utilities license software for the calculations. I once got very good help on this from the local utility, for the specifics of wire, span, etc. they generated a table of temperature vs tension.

 

[electrofelon]

Proper tensioning of the messenger cable vs temperature is important. Most utilities license software for the calculations. I once got very good help on this from the local utility, for the specifics of wire, span, etc. they generated a table of temperature vs tension.

I wouldn't think it would be that important for a messenger supported cable. I have never done it scientifically nor seen the power company do it. Typically they are not very long and never anywhere near tight enough to cause problems in cold temperatures. Excessive sway doesnt really matter because everything is insulated. Now bare conductors on poles, that is a different story.

 

[tortuga]

Why insulate it though? Not enough clearance?

 

[Carultch]

Why insulate it though? Not enough clearance?

Because it would have to be a wire type specified in 690.31, for the DC-side of the system. Once on the AC side of the system, you can wire it like you would any other AC circuit of the same voltage and current. But the DC side has PV-specific rules that govern it, due to several added hazards. Such as the lack of voltage zero crossings that exacerbate the possibility of arc faults, and the fact that if this is prior to any fusing or disconnecting means, there is no shutoff for the circuit other than a sunset.

 

[tortuga]

Because it would have to be a wire type specified in 690.31, for the DC-side of the system. Once on the AC side of the system, you can wire it like you would any other AC circuit of the same voltage and current. But the DC side has PV-specific rules that govern it, due to several added hazards. Such as the lack of voltage zero crossings that exacerbate the possibility of arc faults, and the fact that if this is prior to any fusing or disconnecting means, there is no shutoff for the circuit other than a sunset.

Thanks for pointing that out Carultch, I never noticed 690.31 says all "raceway and an cable wiring methods included in this code", I always read it "all wiring methods included in this code"
i retract my article 398 or 399 idea

 

[electrofelon]

Thanks for pointing that out Carultch, I never noticed 690.31 says all "raceway and an cable wiring methods included in this code", I always read it "all wiring methods included in this code"
i retract my article 398 or 399 idea

I think messenger supported wiring is still in. Looks like it would have to be 600 volts or under for other than industrial establishments, unless one could find "Other factory-assembled, multiconductor control, signal, or power cables that are identified for the use" per table 396.10(A). The floodgates open for industrial establishments in 396.10(B).

Also looks like 396.2 doesnt allow field plexing. It could be field lashed or use "rings and saddles"

 

[petersonra]

Also looks like 396.2 doesnt allow field plexing. It could be field lashed or use "rings and saddles"

I think you could still "plex" it yourself as long as you also used some other method to keep it together. can you field lash it with some nylon wire ties?