Ok troubleshooting wizards

[ramsy]

Ok George, I cut & paste this one here.

Since, Wiggy's require some amperage to move the solenoid they can be used to varify current, along with the voltage reading. But, amp sensitivity varies on solenoid testers, and when shorting a lifted svc.neutral with an open disconnect, ~1.9vac may not move a solenoid at all. So, I thought a digital meter's mA function may best confirm current in this case (whatever the source).

A normal Hz function can confirm if the source of that current includes Zero-sequence neutral harmonics or noise, only if frequencies greater than 60Hz are the dominant magnitude. And, as I understand it, since positive and negative sequences (usually cancel each other on the phases) they are less likely to be a dominant magnitude.

So, a DMM can not replace expensive harmonics meters, further harmonic current won't add like harmonic frequencies, but DMM's can confirm current, and Hz frequencies that are the dominant magnitude.

I have a Fluke application document, explaining how to find harmonics without expensive meters, but you'll need to PM me with an email for a copy of that PDF, since mikeholt's attachment feature doesn't work for me. If it works for others, maybe my browser's cooky settings need to be adjusted?

On Apr 30, 2006, jg3317 wrote in mikeholts Power Quality forum,

I will have to admit I was and still am confused by the readings I received. I took my digital meter that has Hertz reading and placed meter between to cables I removed and the neutral bar and had a reading of 147 Hertz and was not a steading reading jumped from about 130 to 180 hertz.

AKA triplen or Zero-sequence harmonics. Meter reads the highest magnitude, so congratulations, you caught the big one without buying a costly analyzer.

I had to use Google's cach of mikeholts forum, since the 2 month old link is broke. Googles advanced search was used to specify mikeholt.com as the URL, then typed in my search term, since mikeholts search feature can't find phrases. http://72.14.203.104/search?q=cache:TRV2A474420J:www.mikeholt.com/codeForum/viewtopic.php%3Fp%3D1189941%26sid%3D5a228c1fd408ac7e98b77c07ead8b958+ramsy+%22the+big+one%22+site:mikeholt.com&hl=en&gl=us&ct=clnk&cd=1

Google's cach shows the whole thread, so you must brows to the very bottom of the page to see the post above.

 

[gobblerhuntr]

Got a Ronk "blocker" in today, gonna try to get it installed before the end of the week. Haven't opened the box yet, got a call from the office saying it was in. If it has any helpfull info in it I will make sure and post it.

 

[benaround]

What is the reason for attaching the feeder EGC to the aluminum ramp ?

Shouldn't there be a seperate structure,sub-panel located in close proximity

to the devices being fed? The sub-panel would have a GES per NEC, and a

disconnecting means locally to disconnect all the ungrounded conductors

at the same time?

????????

 

[hillbilly]

Hardworkingstiff....Did you resolve your problem? How?
steve

 

[hardworkingstiff]

Hardworkingstiff....Did you resolve your problem? How?
steve

I just spoke with the PoCo rep. They are still tied up on Bald Head Island and hope to get to it next week.

I told him if I didn't hear from him by next Friday, I'll call him again.

I'll let y'all know what they say and what happens.

Thanks for all the input everyone!

 

[hillbilly]

Got a call about someone getting shocked when they put their hand in the water at a homeowners association's docks. It's one that I helped remodel back in February. Marina Power and light power centers with a light and GFI receptacle only (no shore power for boats, they are small boats). Panel is about 150? from the ramp to the floating docks. Ramp is aluminum. I ran 4 #6?s (cu.) in PVC and non-metallic flex from the existing panel to the dock and loop fed the power centers with ? of the pedestals on one circuit and the other ? on the other (used 30-amp breakers). I also bonded the aluminum ramp to the ground wire I ran for the power centers.

Here is what I found. With one test lead in the water and one on the ramp, I found 1.9 volts AC. Switched to DC and found less than .01-volts (discounted it as meter sensitivity). I turned off the 200-amp MB in the panel and found the 1.9-volts still present.

I quickly dipped my hand in the water while holding the ramp and felt a little tingle. It was weird though, like only on one finger in one certain area of the finger. I bent that one over and dipped the other three fingers and no sense of shock. I put the ?shocking? finger back in and again the tingle (fairly strong). It turns out that I have about a ?? diameter abrasion from work this week and the 1.9-volts caused the tingling there, but not on my normal skin.

Love to hear comments please.

Thanks,
Lou

hardworking stiff.....Did you ever resolve this problem? How did it turn out?
Just curious
steve

 

[hardworkingstiff]

hardworking stiff.....Did you ever resolve this problem? How did it turn out?
Just curious
steve

Steve,

I spoke with service man and he said their service lateral was fine. I had some additional questions (like did you isolate the high voltage grounded conductor from the ground rods temporarily to see if the voltage came from your distribution conductors) and he referred me to their engineer. I spoke with the engineer and he was busy but was going to check into it. He called and left a message to call him back and I now owe him a call.

Hopefully we can get this updated next week.

 

[LarryFine]

He called and left a message to call him back and I now owe him a call.

"Tag, yer it, baggy-eyes!" ~ Bugs Bunny

 

[ramsy]

Without seeing any evidence of line-side leaks I would not expect the PoCo to demonstrate any urgency or genuine-liability concerns.

It seems, just like fighting traffic tickets, we must get mad enough to prove how the evidence fails the cited-code requirements.

If I got mad enough, and the client wouldn't pay or permit me to disconnect the service, for a cold-neutral test, documenting the rogue-frequency-current imbalance with a hot tester would be very tempting.

Renting something like this LEM300 may do it nicely; with and without shorting that ramp to waterway.

 

[hardworkingstiff]

<sigh>

<sigh>

Met with the PoCo engineer and field supervisor. The voltage between the ramp and ICW was .9 volts AC. They said it's just stray voltage and it cannot be avoided. They are doing nothing else about it.

I called the homeowner's association rep and explained it to him and he said they had already decided if the power company didn't have a problem then they were not going worry about it since the voltage is not life threatening.

I guess I'm going to speak with the Chief Electrical Inspector about this then let it go if he does not want to get involved.

 

[hillbilly]

Sounds like you've done your part.
steve