Monitoring wires in with PV conductors

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conductors of different systems 690.4

conductors of different systems 690.4

mixing different systems in PV is not wise and it is not code. As most of you know DC and AC systems need to be apart in the PV world [300.3(C)1], and the same is for all signal wires i.m.h.o the intent is important here. PV array source circuits may not be mixed [690.4 (B)]. It is not explicit re. signal or low voltage systems, clear on the AC vs. DC.

If you have PV source circuit ever arcing into a signal wire it can make for a "bad day". The array can never be shut down really, and if it ever shorted out with the CAT 5, well it would be a real mess until the sun sets.

725.136 may help as well

tailwinds,
Heilos
 
I can't comment on what "code" will say on Tallgirl's setup, but I'll come down firmly on the other issues.

a) I can't believe she'll have *any* experience issues unless she first wraps herself in the CAT5 while running a 400A arcwelder. I've also often heard "oh there will be interference if it's too close to XXX" and I say "show me..." Silence reigns.

b) Anyone that gets involved in an BPL/PLC scheme deserves their fate. You might get away with a short run IFF you are prepared to deal with the effective data rate. TCP/iP is, after all, incredibly robust and tolerant; it will be be the hare when it can, and the tortoise when needed. But the users are never so patient. Just Say No.

BPL was the "If we hype it, they will come" of the previous Administration's FCC policy. It's done about as well as the Cubbies. The last real attempt at BPL, in Manassas Virginia, has blown though money faster than a Califunny gubernatorial race; and been as successful -- it's been abandoned.
 
Just a bit of following up --

The contractor couldn't source the panels for the install (not unusual -- seems solar panels can't be made fast enough at times) and has since stopped answering my "When are you doing the install? When are you ordering gear?" e-mails, so the entire mess has been put on the back burner until I hear something.

The plan is to let someone else run the signal wires outside of the conduit, thereby completely avoiding the issue. Which is okay, since I couldn't find anyone who could supply less than 1,000' rolls of the wiring need to run in the same conduit as the PV conductors.
 
gar said:
Somewhat different subject. In Texas over a years time how many KWH of inverted output, in other words usable power, can you expect from a 1 KW array?

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You have to use the NREL (National Renewable Energy Lab out of Sandia) tables for your exact location. We get 5.1 hours average of "full sun" where I'm at. Take the array size (1KW) times the average hours (5.1) times the efficiency (NREL says 77%) times 365 days, and that's KWh per year. If you have a battery-backed system, take off a few percentage points from the efficiency for additional gadgets and "float" charging batteries all day.

I make something around 4,500 to 5,000 KWh DC per year out of a 2,800 watt array. I'm having shading issues that will require a chainsaw to solve, but otherwise I get what I'm supposed to get, based on the numbers I gave you above.
 
101210-0835 EST

tallgirl:

Thank you for the information.

From your first paragraph I calculate 1.433 as the ratio of yearly KWH to Array wattage for your location, Texas. You did not say whether this was DC or AC output.

Your second paragraph provides a ratio of 1.607 to 1.786, considerably better than 1.433, even with shading. Is this because your second paragraph is measured at the DC point, and maybe the first paragraph is based on AC?

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Gar,

The first includes the entire conversion from DC off the array to AC out the inverters. My comment about my solar array is just straight-up DC from the array, with only wiring and charge controller conversion losses included. Some of those losses are already included in the NREL fudge-factor.
 
dereckbc said:
OK sounds like Thermostat or Thermocouple wire to me eh? Key is the insulation voltage rating.
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What was proposed was straight-up Cat5 that's rated CMX/CMR/CMG.

Customer has since run their own conduit from the attic space into the power closet. The installer is still (last check) backordered on 39 Kyocera KD-215GX (or whatever) and the install STILL hasn't started.

And for the solar geeks, the balance of the kit is 2 x OutBack FM-80 for the solar array charge controllers and 2 x OutBack GVFX 3648 for DC-to-AC inverters. No clue about the batteries, but the "matching" system (only difference is 210's instead of 215's) is 12 x 8D8G Deka's. Daily DC output is phat.
 
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