On Sat, 27 Apr 2019 17:37:48 -0700 (PDT), Its Me
wrote:

On Saturday, April 27, 2019 at 5:46:28 PM UTC-4, wrote:
On Sat, 27 Apr 2019 13:31:59 -0700 (PDT), Its Me
wrote:

On Saturday, April 27, 2019 at 4:00:01 PM UTC-4, wrote:
On Sat, 27 Apr 2019 11:21:11 -0700 (PDT), Its Me
wrote:

On Saturday, April 27, 2019 at 1:44:28 PM UTC-4, wrote:
On Sat, 27 Apr 2019 09:59:10 -0700 (PDT), Its Me
wrote:

On Thursday, April 25, 2019 at 10:02:15 AM UTC-4, wrote:


"Flop around"? Each conductor is securely attached to insulators.
They are not physically twisted in a bundle, they just get an
electrical twist by having the phases change positions from pole to
pole. They call it transposition. It allows the lines to be balanced.
(Relative inductance to each other and to the environment around them)

Oh, I thought you were saying that each *leg* consisted of three twisted conductors. I've never seen that but who knows what FPL might be doing.

Transmission lines overhead are bare wires. They are twisted strands
but that is just to increase flexibility and skin effect. The twist I
was talking about is how the lines get "transposed" on the poles every
half or so where they all get swapped around


Those solar panels aren't part of the grid, and have no "sync". Sunlight isn't 60 Hz.

The inverter will be grid tied so the transport to the house would be
in sync.

Of course, but it wasn't the feed to the house that I was talking about.

You think there will be some voltage induced into the panels?
I am not seeing that on anything that is terminated in any way. In
this case the panels would be terminated into the inverter and if
there was any 60hz present it would simple be chewed up and spit out
by the inverter anyway. After all it would be "in sync" with the grid
anyway.

I don't know, I've never played with it, but it can induce some noise. Probably not enough in that situation to do anything at all.

Years ago I installed some comm equipment in a train yard. We had built some interface cards for some comm circuits that was just a 600 ohm twisted pair that ran along the track for miles until it hit a transmitter shack, sometimes with a handset in there to talk back to dispatch. The interface card had a transformer and some audio switching circuits, and was protected by a couple of MOV's rated at 160-180 volts, one for each side of pair going to ground.

When we installed the new equipment and started testing, some of those circuits had a horrible amount of noise and buzzing on them. Doing some troubleshooting with a butt set, I discovered that if our interface card was disconnected, the noise went away. Then I hung an oscilloscope on one side of the pair, then the other. There was a HUGE 60hz component coming in on some of the circuits, in some cases around 200 volts. Since the twisted pair was doing what it does, you didn't hear that on the circuit (when you induce a signal on a twisted pair, the same signal is present on both wires.
Since you only care about the difference in potential between the two wires, the signal stays intact.). It wasn't until our interface card was connected that the MOVs saw that voltage from each wire to ground and turned on, unbalancing the circuit and causing the noise to be audible.

Turns out that the pairs left the yard and were run on power poles, occasionally in some cases dropping down to fence posts on the right-of-way, then back up to the posts. They picked up the induced signal from the power lines and brought it right back to our interface cards. We clipped out the MOVs, and all was good. We had to depend on primary lightning protection to protect the equipment. The MOVs were secondary.

More likely you were simply seeing the ground shift induced by using
earth as part of the return path. That is inevitable with wye
distribution, even if you do have a neutral conductor. Current does
not take the path of least resistance, it takes ALL paths. The voltage
drop on distribution lines is imposed on the earth. When we were
investigating blown interface cards at a college campus I found up to
35 volts between "ground" on the various buildings. We found a number
of solutions depending on the topology and geography but some
customers just turned it over to the phone company, using leased phone
lines between buildings that were a hundred yards apart. The other
solution was copper, bonding "grounds" together, usually from machine
frame to machine frame directly. We had to call it a "drain" and use
black wire to avoid NEC problems.

Nope, this was voltage induced into long runs of unshielded, twisted pair wires. Across the pair you didn't see it, but compared to ground you (properly) did. It's basic electronics 101. Unbalance the pair, which the MOVs did, and now the differential between the conductors is significant and you can hear the induced noise.

It's exactly why RS-232 data is only good for 50ft (or with special, low capacitance cable up to 1,500 feet), and RS-422 is good for nearly 5,000 feet. RS-232 is single ended and is compared to ground (which you can't shake with induced noise), while RS-422 (or 485) is twisted pair. Hit the 232 with a 25 volt spike, and you just changed a 0 to a 1. But with 422, you are looking for a 5 volt difference between the wires. You don't care if they are 0 and 5 volts, or 20 and 25 volts, the data is still intact. Well, until it hits 1000 and 1005 volts, then you've blown up the receiver chip. But the data was still good!

I am not going to argue with you but I was a physical Planning rep in
a place with 200 thunderstorms in a typical year and I know what works
and what doesn't. I have seen a lot of well credentialed EEs, usually
from up north, fail miserably with their theories. The proof is always
in the magic smoke that escapes when they guess wrong.
We went from a couple "lightning" calls a day to a couple a year once
we started implementing our strategies and ignoring all of the "ground
loop" loonies.

That's nice and all, but we aren't talking about thunderstorms. I've worked with many non-engineering types that thought they knew what they were talking about, but many of their practices were flawed, and it showed through in the end. Your attitude isn't uncommon. It's similar to class warfare, eh?

Bottom line, I was dealing with induced AC on a twisted pair that was enough to turn on 180v MOVs. You can talk about ground differentials all you want, but that had absolutely NOTHING to do with what was happening in that situation.

Have a good evening!

You said the line to line was nominal so where was the MOV referenced?
To "ground"?