stray voltage

[1st Class Husker]

See if anyone and help out on this one!

Had a call in a single phase underground hog confinement, workers were getting shocked when spraying the pens down with the hotsy sprayer! Did some checking and found that going from metal building to ground it measured 7 volts! Measured from ground to elbow arrestor and measured 1.3 amps!
We first thought it was our side, so we started opening the neutrals and dumping all phases and reenergizing them one by one, NO Change!
There are 8 hog barns so we dumped the disconnects and one by one started picking the load back up. By the time all 8 barns were disconnected we had .7 volts with leaving the wells still on. Another kicker is when the emergency generator kicks in the stray voltage immediately goes away!

what is everyones thoughts!

I guessed in the generator transfer switch!

[BigClive]

Is the frame of the metal building in good electrical contact with the ground? (earth rod?)

Is the spray washer properly grounded? It could be IT that's giving shocks to ground.

[CPOPE]

See if anyone and help out on this one!

Had a call in a single phase underground hog confinement, workers were getting shocked when spraying the pens down with the hotsy sprayer! Did some checking and found that going from metal building to ground it measured 7 volts! Measured from ground to elbow arrestor and measured 1.3 amps!
We first thought it was our side, so we started opening the neutrals and dumping all phases and reenergizing them one by one, NO Change!
There are 8 hog barns so we dumped the disconnects and one by one started picking the load back up. By the time all 8 barns were disconnected we had .7 volts with leaving the wells still on. Another kicker is when the emergency generator kicks in the stray voltage immediately goes away!

what is everyones thoughts!

I guessed in the generator transfer switch!

http://www.mrec.org/pubs/svd.pdf

Check out this definition and NEC code requirement

Equipotential Plane. An area where wire mesh or other conductive elements are embedded in or placed under concrete, bonded to all metal structures and fixed nonelectrical equipment that may become energized, and connected to the electrical grounding system to prevent a difference in voltage from developing within the plane

547.10 Equipotential Planes and Bonding of Equipotential Planes.
The installation and bonding of equipotential planes shall comply with 547.10(A) and (B). For the purposes of this section, the term livestock shall not include poultry.
(A) Where Required. Equipotential planes shall be installed where required in (A)(1) and (A)(2).
(1) Indoors. Equipotential planes shall be installed in confinement areas with concrete floors where metallic equipment is located that may become energized and is accessible to livestock.
(2) Outdoors. Equipotential planes shall be installed in concrete slabs where metallic equipment is located that may become energized and is accessible to livestock.
The equipotential plane shall encompass the area where the livestock stands while accessing metallic equipment that may become energized.

[JAKE]

are yall on a grounded wye system?

one of the last ones i ran across at a dairy barn fed by a single phase service they had a radio plugged into a non polarized plug backwards and that was causing the stray voltage they couldnt get the cows into the milk barn they wouldnt come up the ramp since thats where the differnce in potential was.

the one before that i had was 4 services upstream from another dairy at a trailer house they had an old single phase 110v well pump that had a shorted pump and since it wasnt properly grounded it was causing stray voltage all the way down to the dairy.


do they have any thing before the transfer switch? or is it at the service entrance? sounds like they have the generator grounded better than the service or the generator is taking care of the issue.

we have been putting ronk blockers in where we have had the stray voltage issues to isolate the neutral and cover our side since most of theese farmers and dairymen wont get someone out there to do it right, the only time they will is after they have had a brush with death from electricity <- just makes me think of the dutch dairymen has his burned handprints on a 480 delta disconnect....

[Trbl639]

we had a similar situation on a swimming pool at a house...floated the neutral on the pot that fed it (only customer on that pot) and it cured it!!!

[King]

I got a similar call a ladies horses were getting shocked when they stepped off the rubber mat in their stalls onto concrete in the barn. While I was asking the lady when it seemed to happen I leaned up against her truck and got shocked. It seems the truck had an AC block heater on it that had malfunctioned. Current was running back on the ground wire of the plug and causing the concrete to have voltage on it.

[Troubleman730]

This happens a lot in the sandy soil of N.J. We found that swimming pools create a better ground than the system neutral. Thus causing all the inbalance from the system to discharge through the Swimming pool, or wet pump area. Bonding the entire area sometimes helps.

[CPOPE]

Hydro jolt hits students
Sparks $15M inspection
Last Updated: 31st January 2009, 4:43am

Several students being shocked by stray voltage has prompted Toronto Hydro to spend $15 million to mobilize 600 workers to work round-the-clock inspecting its aging street-level infrastructure.

Three to five students from Regent Park/Duke of York Junior Public school were zapped but uninjured Thursday, prompting Hydro president and CEO David O'Brien to announce the mobilization -- the largest in the utility's history -- at a hastily called news conference yesterday.

It's the first time a child has been struck by stray voltage and comes after two dogs were electrocuted and several were shocked in the last two months.

"Parents are just going to have to be careful until we can get it done," O'Brien said. "If you see (handwells), don't step on them."

Adults are getting zapped, too, Talia Russo said.

The 28-year-old was walking on Spadina Ave. earlier this month with her younger brother when they felt a shock on the northwest corner of Wellington St., she said.

"It was strong enough to make me scream 'Ow!' " the 5-foot-1 Russo said yesterday, comparing it to stepping on something sharp but feeling it all the way to her knees.

'I'M SCARED'

"They have to do something about it if children and adults are feeling it -- I'm scared to walk anywhere in this city."

Russo said she mentioned it to a Toronto Hydro worker on the street later that day.

Regent Park residents were upset to hear about children getting jolted on their streets.

"That is a real problem and I think an investigation is needed to find out what's going on," Malcolm Babbage, 31, said. "This is occurring all the time and now we've got to worry about our kids stepping in the wrong place?"

'VERY SAFE'

Mary Watson, 43, a mother of three, said she wants to know what's being done to make sure other handwells are not going to be a problem.

But O'Brien stressed Toronto's streets "are very safe," and the utility is addressing the stray voltage aggressively. "We're going to get it fixed.

"We are taking our workforce off everything else they do and this is all they are going to be doing until they get it fixed."

On Thursday, several students told teachers they received a shock near the corner of Dundas and Sumach Sts., Toronto District School Board officials said.

A letter sent to parents from the principal stated staff determined that each of the students had stepped on a handwell.

TDSB spokesman Kelly Baker said the children appeared uninjured but cautioned parents to take them to their doctor just in case.

About five blocks from the school, a hydro crew found a handwell with stray voltage.

The utility had already allocated $10 million to sweep for stray voltage and replace metal handwells after the electrocutions of a German shepherd in November and a Labradoodle this month.

O'Brien said in the wake of the incident involving kids, the utility opted for a blitz, costing an extra $5 million.

"This is going to cost an awful lot of money but you can't put a price on a life," O'Brien told the Sun.

[Avid]

Myself and two other JL were sent out to troubleshoot stay voltage on 4800 delta. A lady would get a jolt getting out of her swimming pool, and grabbing the metal hand rail. We measured 2.x volts there.

Long story short, the neighbor's house (only other one at the same pot) didn't have their panel attached to a ground rod, and the cable company had attached a ground to top of their meter box. At that wire to ground - 56 volts! Disconnect the cable line and it went away completely. Remove the cable ground wire and again it went away, so we left it off and reported both issues to engineering.

We were there for a few hours to figure that one out! I never heard what they ended up doing, or whether grounding their panel caused it to bleed off.

[CPOPE]

(Posted Date: Monday, February 2, 2009)
Dusko Avramovic says his family is “still in shock” over the loss of their beloved dog Mrak, a Labrador-poodle mix.
Dusko Avramovic knows his family is struggling to keep going after the loss of a very close friend.

On Jan. 13, his 25-year-old son Darjan was walking their Labrador-poodle mix, Mrak, in the Keele and Annette Sts. area when the dog unexpectedly dropped to the ground.

“(My son) was panicked when he was trying to call me,” Avramovic recalled. “I left here to run there, and I found (Mrak) on the sidewalk motionless.

“When I actually tried to hold him with my arm, I felt a shock,” he added. “It surprised me, out comes a shock like this. And then I figured out he stepped on that plate.”

The incident sent a tremor of emotion through the family.

“How are we coping? Terrible,” Avramovic said, sounding distraught. “The kids: when they wake up, they’re crying first, then they go to university. When they come back, they’re crying again.

“It’s unbelievable.”

Disbelief shifted to irritation when asked what Toronto Hydro should do with stray voltage, believed to be the culprit behind Mrak’s death.

In November, a German Shepherd suffered the same fate while out for a walk with its owner near Keele and Dundas St. West.

“In this case, we’re talking about dogs,” said Avramovic. “It’s not going to change until something worse.

“What if you bent to pick up something and you touched a plate?” he added. “Waiting by the bus stop, people taking change from their pockets, how many times have they dropped something? If you try and pick it up and touch a plate, you’ll get shocked and get killed.”

In response, Toronto Hydro is moving forward with a citywide sweep to detect any stray voltage.

“We’re treating the matter very seriously,” Hydro spokesperson Denise Attallah said. “It’s a safety concern for us, so we’re starting our citywide customer campaign.”

The utility established a hotline on Jan. 26 and is urging anyone concerned about errant current to call 416-222-3773.

In addition to the hotline, Toronto Hydro will replace metal handwells with non-conductive ones, splitting $10 million between the project and the safety sweep. Stray voltage is electricity present on a structure or surface that shouldn’t be energized.

How safely electricity is transported from one source to another has triggered concern in Councillor Bill Saundercook, who serves on Toronto Hydro’s board of directors.

“Toronto Hydro . . . (is) scanning the entire city with this infrared technology to look for the stray current that’s culprit in these situations,” he said.

Saundercook said people are at low-risk of being shocked because of rubber-soled footwear.

However, he said the use of salt and the pooling of water during winter contribute to a “toxic mixture” for the animals.

“I had asked Toronto Hydro and city transportation to explore the use of sand only,” he said. “That way, you might eliminate the pooling aspect of it. They replied that they’d thought salt was very minimally contributing to the problem.

“They wanted to attack the problem at its root and not at the surface.”

Still, Avramovic wants the city to change its safety codes for electricity, especially after two more dogs were zapped in Yorkville. They were unharmed.

“They have to ground something,” he said. “In the house, you have a metal box for the switches (and) the box has to be grounded. That’s the same thing.”

Whatever is done is unfortunately too late for the family’s beloved Mrak.

“I’m still in shock,” Avramovic said. “Wherever I turn around the house, there are memories of a beautiful dog — I could say person, friend.

“Not only ours, but the whole neighbourhood’s