# Utilizing a 10kva transfomer for my AV panel



## Talley (Dec 8, 2010)

First of all... take a look here: http://www.ebay.com/itm/182004098001?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I was quoted this exact unit new from my supplier $586 + tax. I just offered $175 for this one used and it's free shipping and they accepted! No clue how they will make money after ebay charges they net 155 and shipping a 125lb transformer they are practically giving these away. 8 left in stock.

Now.... Many here know I have a separate panel dedicated to my AV panel but I want to isolate this panel from my main panel and also keep everything to a 120V system without sharing any neutral to the rest of the system. I will wire this transformer with 240V on the primary and on the secondary wire series so it’ll just be 120V derived from the 240V feed. This will give me a separately derived system and help me isolate me from the mains but more importantly not share its’ neutral from my house or my neighbors. 10kva means I'll get 83 amps of capacity to my panel at the 120v. I could later on decide to just do a 240/240 isolation but this is a standard dry type distribution transformer and not necessarily an "isolated" type even though this unit is isolated meaning the primary and secondary windings are not connected and there is a shield in between these windings so I will be benefit from noise reduction on the lines. Also by combining the 240v line side that contains no neutral and providing a secondary 120v source I get my own dedicated neutral.

I'll bond this transformers neutral to the separate ground rods I have installed for my isolated grounding on my AV panel. This ground rod is NEC compliant because it is bonded to the main panels ground rod under ground. This is the only point of bond... in earth.

I’ll post photos of the progress and keep this thread updated for this installation.

Feel free to comment and/or ask any questions or tell me how lame this is lol.


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## robbo266317 (Sep 22, 2008)

Sounds like you got a bargain, What would the copper be worth as scrap?


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## Talley (Dec 8, 2010)

robbo266317 said:


> Sounds like you got a bargain, What would the copper be worth as scrap?


This particular xfmr is aluminum. New price was 586 plus tax for the copper wound version it is 844 plus tax.

Your service to your home/neighborhood/transmission lines are all aluminum and most of your overhead distribution transformers are aluminum as well. I picked it up for the price with intention later on doing a double transformer... I'll add a second and have them in series 240 > 120 on one and 120 > 120 on the second with a UPS in the middle and the second will be copper.


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## tonyvdb (Sep 5, 2007)

Is your electrical grid so poor that you need all this extra effort? I'm using two dedicated circuits off my main panel and have never heard any noise in my system and my two ethereal power conditioners never fluctuate more than a couple volts up or down at 120v


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## Talley (Dec 8, 2010)

tonyvdb said:


> Is your electrical grid so poor that you need all this extra effort? I'm using two dedicated circuits off my main panel and have never heard any noise in my system and my two ethereal power conditioners never fluctuate more than a couple volts up or down at 120v


Two words -> Overkill haha


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