low voltage: transformers vs bigger wire

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  #1  
Old 07-23-02, 07:41 PM
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Steve Mclean
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low voltage: transformers vs bigger wire

Hi All,

I will likely have an electrical contractor out to make recommendations. I called re transformers (Acme) and was told I needed two transformers. One at start of run to up voltage to 480 or 600 and one at end of line to knock it back down to 240. I was quoted almost $1000 for each 480 transformer; so $2000 plus installation charges. On the other hand, according to my calcs double 0 wire has been quoted at $.92/foot and may do the job for less than transformers. (I need apx 1500 feet for two hot wires of 750 feet each.) An electrical contractor also said I could use #2 wire for a neutral and #8 for a ground. Does that sound correct? If I pull the old Aluminum cable bundle out, I can use it elsewhere. I don't think Edison is capable or willing to up the 10KVA transformer voltage as someone suggested. Any input will be appreciated.

Steve
 
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  #2  
Old 07-23-02, 08:13 PM
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Is the wire cu or al ? Would really pay to shop for wire on this one. Supply house can beat Home Depot. Ask a bud to get a price under a contractors name,,, someone that uses a lot of wire. I have even went to the counter and mention the words ,, I priced at Home Depot,,, ha,,, they take pride on outpricing them. You may do well on a 3 wire bundle also.
 
  #3  
Old 07-23-02, 08:18 PM
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MTgets
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Steve,
this is the fourth thread you have started on the same issue, it is very difficult for people to follow along as everyones problem is read and learned from, please stay with this thread and just keep posting back here, even if it is 100 replies back and forth so what, just keep it here.

Thanks
 
  #4  
Old 07-23-02, 08:24 PM
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Steve Mclean
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Understand the change in subject. Sorry, but my Q was a bit different and I got no response to last post. Wll stick with this subject awhile. I love driving people nuts so they're just like me.

I am shopping the wire. So far all around .90 cents/foot for double ought copper. Anyone sell on line? Whats this about a three wire bundle? Didn't know it could be bought that way.

Will all this fit in a 2 inch conduit?

Steve
 
  #5  
Old 07-23-02, 08:29 PM
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Wgoodrich
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Some transformers but not all transformers have a buck boost set of lugs in the transformer. Line one would have three lugs and line two would have three lugs. One lug would be - 5% or - 10% voltage lug two would be base voltage without up or down boost or buck. Lug three would have a + 5% or + 10 %. All the above lugs would be grouped for line one. Then a second set of three lugs would have the same grouping of + or - buck boost.

The purpose of these type transformers are to up the voltage a small percentage without the need for 2 transformers to boost to 480 then buck back down to 240 volt.

A single transformer can most likely boost the voltage the percentage that you need.

Some Utility transformers have these same + or - voltage adjustments. Can't hurt to ask if they can help you or if the transformer you have can do this voltage adjustment. All it takes is to move line 1 and line 2 over to an adjascent lug, if they have those type transformers.

If the Utility company does not have this type transformer, then check a few suppliers or manufacturers that may be able to supply an adjustable voltage transformer.

If you opt to install two transformers and over size you wires also which may save you money then you don't have to install a neutral conductor on that long run. Your transformer can produce that center tap transformer to produce the new neutral at that transformer by the home. YOu would only need two conductors between transformers.

You also have an option of using the wires you have and buying the same size wire again making a parallel run beside the existing feeder conduit. The voltage drop would be reduced using the circular mills combined of both parallel feeders thus allowing you to buy a much smaller wire utilizing your existing feeder and doing the same thing at half the cost.


Hope this helps

Wg
 
  #6  
Old 07-24-02, 07:48 AM
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wg, or anyone,, Seems I bought some 2-4/oo and 1 2/00 urd or something like that,, Alum,,, It was really reasonable. I know the house sold it. Can the neutral be derated in this case. I was using it to subfeed for wells so all the load was 220 but could it be used for Steves app? It was cheap,, like a 110 per foot. Been a while and I dont recall without looking it up. I know the jobber was by far the best price.
 
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