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Running Electricity Over Long Distance
#81
[quote][i]Originally posted by ric
I've heard there may also be issues with voltage loss over a long power line.

The bigger your current draw (turn on microwave, or elect water heater) you get a voltage drop due to the resistance of the wire.
Voltage = Current x Resistance, given a fixed Resistance the bigger the Current the more voltage drop. The trick to minimizing the line loss is to run your lines as far as possible with the HELCO transmission voltage (typically 13,500 volts or 13.5 kilovolts) and have your step down transformer near your house. Transformer option: on a pole overhead your place, or my preference would be to have one of those green transformer boxes (about the size of a pickup truck tool box) near the garage and run the short distance to the house underground. You may have to pay for the transformer (mainland you do, so I don't know about a "shared" transformer that "may" be provided at the street) I seem to remember hearing transformers running at about $1000 +- ?? given the length of time and inflation since I heard this.
Basically, the higher the voltage you can run an appliance, the more efficient it is. Also, the longer you can run electric at higher voltage, the less current you draw (less heat generated) for the same amount of power used. This is why 240 volt appliances like air conditionders work at this voltage, it would take twice the current to work at 120 volts, and all that current generates heat and needs bigger wires to dissipate the heat and prevent the line losses.
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#82
thanks jimbo. I kind of thought I might need something like that. has anyone on the island done a run of 300-400ft? If so, did they run it at normal voltage or did they run high voltage with transformers? can someone recommend an electrician for this? any idea on costs? thanks
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#83
300 to 400 feet is not that far. You just need to use bigger sized wire.
If you are running underground you can use copper instead of aluminum. Copper has a higher amp rating for a given wire size, but is more expensive.

Also remember that voltage drop depends on load. If you are going to have a shop with a lot of power tools this should be factored in. If it just a small house with gas appliances, then the calculation would be different.



Jerry
Art and Orchids B&B
http://www.artandorchids.com
Jerry
Art and Orchids B&B
http://www.artandorchids.com
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#84

No need to fool with high voltage and transformers. jerry (above) did ours 300+'. I did the poles and Jerry did the panels and ran the overhead wire. I don't have a breakdown on cost, but if you contact Jerry, I am sure he can give you some ideas. You will be happy if you hire Jerry. I am.

Hi Jerry. Dan
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#85
has anyone on the island done a run of 300-400ft?


I ran 700 ft no step up transformers, no issues, Just lots of fat wire and a half a dozen galvi poles
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#86
quote:
Originally posted by Bullwinkle

has anyone on the island done a run of 300-400ft?


I ran 700 ft no step up transformers, no issues, Just lots of fat wire and a half a dozen galvi poles


Interresting!!!
Did you do it yourself?
What's involved, if you dont mind me asking? [Smile]
How about Cost?

Chris
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#87
quote:
Originally posted by David M

Back again

Previously, we looked at designing a system based on meeting our stated requirement for daily power - 7820watts for Chris, 15kw for me.

The reality of the situation is the systems will produce more power than the requirement. For example, my current 4.5kw system produced an average of 21.11 kw per day the last week of May. That's 4.69 per kw of panel. That's 140% of my daily requirement.

So how would that translate to the above theoretical systems. 83.6kw produced on the 17.82 system - 557% of requirement.

The no-genset 14kw system would have produced 65.68 kw or 438% of requirement. Basically wasted - can't store it in my current battery bank and adding additional battery banks would add an expense without a benefit. Even if on Helco, couldn't sell them that much!!!!!!

Actually, I don't waste my overage - currently, it's free power to power the pool pump - but that's another story Smile

Anyway. I just hope I've given some insight as to why it's important on this forum to temper theory with local experience.

Any questions? Enjoy [}Smile]

David


Ninole Resident


*Finally having a chance to review the posts.
WOW! David, what your saying sounds like great news!
Am I missing something?

Thanks,
Chris
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#88
Pete:
"So, in our view, in determining the number of batteries, night time consumption probably should be considered more than powering through gray days. Our experience is that most moderate to severely gray days are either marginal or will not meet our consumption needs or maintain battery charge. Rather than having a large array of batteries to power through the gray days (and which the panels may not fully charge on many days) judicious use of the generator (commonly 1-1.5 hours in the evening, don't let the batteries stay low overnight) we feel is a better bet to maintaining charge through the severe cloudy periods. Restoring the night time consumption and gaining a very high level of charge nearly every day, for us anyway, seems to be the critical parameters in avoiding another big bill for batteries. The rest of the system should be reasonably expected to live for 15-20 years. The batteries are the real weak point and must be coddled. "

Thanks for this valubale piece of information!!!!
Chris
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