Why choose 120 volts?

Seth Mattinen sethm at rollernet.us
Tue May 26 17:30:10 CDT 2009


Joe Greco wrote:
> 208 isn't all that great.  On one hand, a 20A 208V circuit is vaguely
> more convenient than a 30A 120V circuit because it is delivering a bit
> more power to the rack (3328 vs 2880), and it's likely to work with a
> lot of modern equipment containing autoranging power supplies.
 >
> On the flip side, with 120, you don't have to have "odd cords," and it
> is somewhat easier to "right-size" power for a rack (20A, 30A, 2x20A),
> so for an average rack that isn't crammed with high power webhosting
> 1U's (etc), a customer might actually find that the ability to right-
> size the power feed is more flexible with 120V.

I don't find it makes much difference, really. People are used to 
working with 120 only because that's how we roll in the USA; scary high 
voltage is for the oven and dryer. I like odd cords; it makes the 
protected power stuff blazingly obvious and slightly harder to plug dumb 
things into a UPS branch circuit because hey, a plug is a plug, right?


> And I don't like not having anywhere to plug in my power screwdriver's
> recharger...  I suppose I should see if I can find someplace that has
> a transformer of an appropriate size, or does anyone already have the
> part number for something that can provide a few hunderd milliamps of
> 120V from 208?  :-)

True, you do lose the convenience outlet factor. I made up for it by 
placing standard 120V outlets (utility/generator only) along the walls. 
It works out because I hate those stupid "wall warts" with a passion. I 
go out of my way to buy products that come with a corded transformer, 
especially if it has a C14 connector on it.

If you're adept at electrical stuff you can always get a small 
transformer, put it in a box, stick a C14 on the high side and a 5-15 on 
the low side. Nothing fancy required.

~Seth




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