graze-l May 2006: [SPAM] - Re: [SPAM] - Re: [SPAM] -
Re: [Graze-l] [SPAM] - Why insulated grounding wire? - Found word(s) barn in
the Text body - Email found in subject - Found word(s) barn in the subject -
Email found in subject - Email found in subject - Email found in
subject
Aren't some electrical systems more prone to stray voltage? Do parts of the
world running everything on two positive legs (similiar to our 220 volt
single phase in US) rather than our one positive and one neutral (which is
tied directly to the grounding system) have less problems with stray
voltage?
I'm fortunate in that I don't milk cows so don't spend a huge amount of time
worrying about stray voltage. I do however have a poultry slaughter and red
meat processing plant. We run all of the wiring as UF (underground rated)
and ran it inside waterproof plastic conduit. Food processing operations
(and I would think milking parlors also) are rough applications for
electrical wiring to keep it dry and out of harms way.
We were behind on rain until the last week and starting about last Wednesday
it has rained and sprinkled just about 24 hours a day.
Greg
----- Original Message -----
From: "leon" <leon@grazinginfo.com>
To: <graze-l@witt.ac.nz>
Sent: Sunday, May 14, 2006 9:21 PM
Subject: [SPAM] - Re: [SPAM] - Re: [Graze-l] [SPAM] - Why insulated
grounding wire? - Found word(s) barn in the Text body - Email found in
subject - Found word(s) barn in the subject - Email found in subject - Email
found in subject
>
> On 15/5/06 10:19 AM, "KV9U" <mrfarm@mwt.net> wrote:
>
>> Hi Charles,
>>
>> Stray voltage is not easy to detect, even for professional engineers
>> working on this problem.
>
> Experts have little problem.
>
>>We have several in our state who work with
>> government and power companies to try and determine the cause. Even
>> measuring mV (millivolts or 1/1000th of a volt) is not always going to
>> help you. Some of these transients are fleeting and can come from miles
>> away from factories, businesses and schools with inductive loads and
>> square wave generation.
>
> Sometimes because of the pathetically small earth pegs close to building
> under eves.
>
>> One way to accurately measure stray voltage is to use a storage
>> oscilloscope which can hold the waveform with its attendent voltage and
>> rise and fall times. This can give you some indication of the source.
>> This type of equipment is very expensive and only a few troubleshooters
>> seem to have it. If the leakage is constant, you could then measure the
>> voltage with low cost equipment since most DVM's (Digital Volt Meters)
>> can see a few millivolts on their most sensitive settings. The other
>> issue is what do you measure across? The standard approach is to
measure
>> between a cow drinking location and a point where the hind feet would
be
>> and measure this across a 500 ohm resistor to simulate a livestock
>> equivalent. They usually use some hydraulic pressure on the floor probe
>> to match the weight of the livestock. The state folks claim that you
>> would need over a 0.5 volt differential to be of concern.
>
> They are wrong. Much less can affect a cow on four feet without gumboots
> and
> with milking machines on tender teats.
>
> In some US rural areas the electricity supply is a disaster, but the
> suppliers will not admit it.
>
>
>> Rick W.
>>
>>
>> Charles Ritch wrote:
>>
>>> Rick,
>>>
>>> You wrote: This can help to reduce any chance of stray voltage.
>>>
>>> How would one check for "stray voltage". I am told the
standard volts
>>> meters, ever thought they measure in mV, are not accurate for
>>> measuring stray voltage. I call my electrical supply house and they
>>> wanted over $700 for a meter that could accurately measure mV.
>>>
>>> Thanks,
>>>
>>> Charles Ritch
>>> Goose Pond Farm
>>> ritch@hiwaay.net
>>
>>
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>
> Best wishes,
>
> Vaughan Jones
> Hamilton
> New Zealand
>
>
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