USA Farm Power supply

@GaryS, I have to ask: does your phone keep correcting neutral to natural? Or is this something new I should learn?


P.S. I worked with some folks in the dairy industry a while ago, and "stray voltage" was an issue that caused a measurable drop in milk production.
 
its ok - trust me I do know - the only info i needed was voltage and frequency
I have been told this uses both 50 hz and 60 hz
 
drbitboy
I think you are seeing a typo between the 2 words sorry i have to watch that

iant
here in the North America the AC supply is 60hz every thing is inter connected to the grid
so it 60hz phase matched 120,240 single phase 208,240,480 3 phase and in Canada it 600v
are the standard but that not to say some private system can use something else

the Rail Roads have their own private power system with multiple generator in multiple power plants most are Hydro 25hz they are only in the north east New York - Philadelphia - Washington DC with a side line to Harrisburg it was never expanded west of Harrisburg it was built in 1920's and still in service
 
drbitboy said:
@GaryS, I have to ask: does your phone keep correcting neutral to natural? Or is this something new I should learn?


P.S. I worked with some folks in the dairy industry a while ago, and "stray voltage" was an issue that caused a measurable drop in milk production.
Click to expand...


Mike Holt has some good stuff on Neutral to Earth voltage as well. You wouldn't think a few volts between the two would cause so many problems.
 
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I thought I was done with this thread but ran across this today
and it it right on point

https://www.fwi.co.uk/business/busi...ning-after-woman-electrocuted-in-farm-caravan

there is just no way to do a proper grounding / earthing if the earth is a return conductor it creates very dangerous conditions
while I don't dispute they many have not had everything as it should have been but with separate return and ground ( As UL ode requires) it all may have been avoided
and she may still be alive
 
GaryS, that has nothing at all to do with SWER.

In Aust/NZ any new house installation, all power, lighting, hot water circuits have to have RCD/earth leakage protection devices. Is this the same in USA?
 
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neither one of us know that, they didn't say much about the electrical system
but that doesn't help here she is still dead
We both have to admit something is definitely wrong there
and I am going to ask you to prove it had nothing to do with SWER
an earth return system is just asking for trouble i have seen the problems they cause first hand
 
PLCnovice61 said:
GaryS, that has nothing at all to do with SWER.

In Aust/NZ any new house installation, all power, lighting, hot water circuits have to have RCD/earth leakage protection devices. Is this the same in USA?
Click to expand...


Your RCD's are basically whole-house GFCI's. For our systems, we use separate GFCI's. We have individual breakers, receptacles, etc. It is just how our equipment evolved. Now, modern codes require arc fault circuit interrupters in just about every area of the house, and dual function GFCI / AFCI breakers are getting to be pretty much common-place. So we do have them, and have them required by code in most areas, but we don't protect the entire house with one device. We do it on a circuit-by-circuit basis.
 
GaryS said:
and I am going to ask you to prove it had nothing to do with SWER
Click to expand...


Fault current does not go to the system earth connection. It goes to the system neutral. Most electrocutions like this happen because a normally, non-current-carrying, conductive surface becomes electrified and has no return path for fault current to open the over-current protective device.


Given that the earth-return on an SWER system is on the system PRIMARY, and the secondary is configured exactly like a standard US residential secondary, whatever is fed from the secondary of that transformer has the exact same fault protection as any other service.


The only difference is that an earth-return system has higher transmission-line losses due to the fact that the ground has a higher impedance than a wire.


Most residential transformers just use a single phase and a neutral wire, anyway.
 
Sparkie, yes we protect from the switch board but we have too have individual circuits protected by a RCD (residual circuit device) not greater than 30mA, which normally incorporate circuit protection (10,16,20amp etc) (RCBO), so you protected at the outlet, so any earth fault happening prior to the outlet isn't protected.
Industrial sites now must also have all 1 phase 240volt circuits protected as well.
 
PLCnovice61 said:
Sparkie, yes we protect from the switch board but we have too have individual circuits protected by a RCD (residual circuit device) not greater than 30mA, which normally incorporate circuit protection (10,16,20amp etc) (RCBO), so you protected at the outlet, so any earth fault happening prior to the outlet isn't protected.
Industrial sites now must also have all 1 phase 240volt circuits protected as well.
Click to expand...


I see that your RCD has a higher threshold. Ours is like 3mA, 5mA or something very close. Is the RCD just used to protect your service conductors?


I think I've misunderstood what you wrote. Basically, we install ground fault protection MOSTLY on a per-receptacle basis. One GFCI receptacle and we protect several others off of that one receptacle. That is our primary method of detecting that current imbalance between the hot and neutral conductors. Our circuit breaker provides overload and short circuit protection. Our main breaker is not GFCI protected.
 
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Our RCD at 30ma are for personal protection, to save your life if you are getting an electrical shock, in hospital surgical theatres it is 10 ma, you sure your protection is as little as you suggest. A healthy human is supposedly able to survive a 30ma shock, were people are in a weaken position i.e. surgical theatres they believe they should survive a 10ma shock.
Ground fault over here is larger ma, on HV regulated to a max of 5 amps, can't remember what it is for LV.
 
l found another article which gives your tripping times, so l see your 5ma can take 6 seconds to trip, Aust/NZ have gone with 30ma and instantaneous trip time, inst being classed as less than 40 milli seconds, were it looks like your 40ma is 300ms (looking at a time/amp graph), although they say most GFCIs trip in less than 100ms? is that because the fault is large who knows as it doesn't say.
 

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