# NEMA Enclosure for indoor use.



## Darren (May 10, 2002)

I need to house a step up transformer and provide a space to terminate the wiring to and from the transformer. This would be mounted in a dry basement and be fed by an inverter with 110/120V.

Other than cooling the transformer are there any other issues (code maybe) that I need to take into consideration?


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## MichaelK! (Oct 22, 2010)

Transformers for AC are readily available with capacities in the watts to kilowatt range. What is the purpose of your transformer and what capacity do you need?

Simple transformers have two standard plug sockets on opposite sides. One would be for 110 input and the opposite for 220V output. Simply turn it around and you would step down from 220V to 110V. I used something like this one when I was operating my computer overseas in a 220V AC country.
http://www.ebay.com/itm/Simran-THG-...329?pt=LH_DefaultDomain_0&hash=item19f9b70809

The one I purchased was no larger than a 500 round brick of 22RF, and needed no enclosure. I'm guessing if this is a battery-powered system, you really can't put together something in the kilowatt range without a really massive battery bank.


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## Darren (May 10, 2002)

The battery bank consists of 8 6V Sun Extender batteries wired in series. What kind of power can that supply?


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## Jim-mi (May 15, 2002)

NEMA 12 is the type of box you need.

I have a huge transformer that would require a box at least 14x14x14" . . .very hard to find. 

Code requirements include "free air space" . . . . . .so don't buy a box too small......

If it is for a 240vac well pump is your transformer large enough to handle the inrush(surge) current ??

If you don't see an inspector eye-balling your project then just free-air mount it.

Yes step up/down transformers in steel boxes up to 5000 watts are quite available..

You have to look at the battery to determine its amp hour rating..........


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## 12vman (Feb 17, 2004)

Are you using a pure sine wave inverter to feed the transformer? If not, the transformer will run hot and you will waste a lot of energy..


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## Darren (May 10, 2002)

I can check the inverter. All I know is that it's an Outback brand inverter. The batteries have a 405 amp hour rating based on 24 hours according to the sticker.


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## wy_white_wolf (Oct 14, 2004)

Darren said:


> The battery bank consists of 8 6V Sun Extender batteries wired in series. What kind of power can that supply?


http://www.sunxtender.com/pdfs/Sun_Xtender_Battery_Technical_Manual.pdf

4,860Wh would be 50% discharge. At that daily usage you'd expect about 1000 cycles or under 3 years life expectency.

WWW


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## Darren (May 10, 2002)

Does that mean a 5kw transformer would handle the load and limit the total load to about 46 amps at 110V?


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## Jim-mi (May 15, 2002)

The only "limiting" the transformer will do is "limit" the current it will pass.

So if the transformer is too small it will not power your load.

Do you know the current requirements of the 220vac load you are proposing to power . .???

I just mentioned 5K transformers as being quite available on flea bay.......

Outback inverters are sine wave.........


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