> Okay this is my last post on the subject. I appreciate the kind words of
> support and always welcome constructive criticism/post-trauma analysis, all
> while rolling my eyes at the know-it-alls who add nothing to the discussion,
> really.
>
> I gotta tell ya it's been really difficult biting my tongue. But my frank
> opinions don't really have a place on this forum.
>
> - Matt
>

THE reason I've never criticized the development team for anything is also the most important thing I learned in medical school and post-doctoral training. Namely, that I don't know what I don't know. The corollary point is, if I procede based on what little I do know as if it is quantity-sufficient information, or worse, as if what I think I know is all there is to know, I'm circling the drain.

---

> > The new database server is a Sun Fire V40z. According to Sun, a fully
> loaded
> > V40z draws 760w. Specifications <a>
> href="http://www.sun.com/servers/entry/v40z/specs.jsp#Environment">here.[/url]
> >
> > This one isn't fully loaded, but it's still going to draw some power.
>
> Those are really, really, really nice pieces of equipment.
> If you want to read a review on one (with lots of nice pictures), have a look
> here.
>
Lets see. 760 watts at 120 Volts is about 7 amps. For a 100 foot extension cord run I would be using 10 gauge wire to avoid voltage drop over that run. This is NOT a $10 extension cord it is more like $150 or so if I recall correctly. The cheap little cube taps that cost $1 or so will also not handle this kind of draw well the ones that will cost more like $5. This last is still not a big item.

I remember the time that someone tried running an air compressor off of 100' of 18 gauge extension cord (the cheap $10 variety). They ended up replacing the motor of the compressor (about $200). At the same time, I put my compressor next to the outlet, and ran air hoses instead...

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BOINC WIKI

Hi Folks!
It is just about 1 A.M. on the East Coast and I STILL am not able to connect with seti to send my program info or download new. Is anyone else still having problems with this? If not, then I will delete my present program and download a new one.
Thanks!
Patti

---

> Hi Folks!
> It is just about 1 A.M. on the East Coast and I STILL am not able to connect
> with seti to send my program info or download new. Is anyone else still having
> problems with this? If not, then I will delete my present program and
> download a new one.
> Thanks!
> Patti

No problem here. I just sent back a WU. What kind of error are you getting?

---

> > Hi Folks!
> > It is just about 1 A.M. on the East Coast and I STILL am not able to
> connect
> > with seti to send my program info or download new. Is anyone else still
> having
> > problems with this? If not, then I will delete my present program and
> > download a new one.
> > Thanks!
> > Patti
>
> No problem here. I just sent back a WU. What kind of error are you getting?
>
>I'm still getting the error -50 message which, I believe, is that it is unable to establish a connection. I am running the classic seti---perhaps that is the difference.

---

seti classic and seti BOINC are two completely seperate systems. If you are having problems with classic, you should post in the classic message boards if you want to see if others are also having problems. However, this might be a good time to switch to BOINC :)

---

A member of The Knights Who Say NI!
For rankings, history graphs and more, check out:
My BOINC stats site

> Lets see. 760 watts at 120 Volts is about 7 amps. For a 100 foot extension
> cord run I would be using 10 gauge wire to avoid voltage drop over that run.
> This is NOT a $10 extension cord it is more like $150 or so if I recall
> correctly. The cheap little cube taps that cost $1 or so will also not handle
> this kind of draw well the ones that will cost more like $5. This last is
> still not a big item.
>
HI John, You're on the right track.

NFPA 70 (USA national electric code) article 210.19 FPN(fine print note)4 dictates that the voltage drop of a branch circuit SHALL not exceed either 3% branch circuit only, or 5% for both branch circuit and feeders.

What this means is that voltage drop from the Service Entrance (Main breaker) to the last device shall not exceed 5%. Also, the voltage drop from the last breaker to the last device shall not exceed 3%.

3% of 120 is 3.6 volts, 5% of 120 is 6 volts. So the drop from the last breaker to the last device (the server) in this case shall not drop to less than 116.4 volts. We do not know what wiring is involved from the last breaker to the receptacle proposed for use in connecting the new server, so, we can't really be sure what size cord to use.

That being said. I've done the calculations using 7 amps as the load, 100 foot as the length of the cable. The voltage drop across an 18 awg wire (line to neutral) would be 5.915 volts, across a 16 awg cord 3.703 volts, across a 14 awg cord 2.282 volts, across a 12 awg cord 1.435 volts, across a 10 awg cord .903 volts.

a 14 awg cord would work if the existing drop from the last breaker to the receptacle were not more than 1.318 volts. a 12 awg cord would work if the existing drop were not more than 2.165 volts. a 10 awg cord would work if the existing drop were not more than 2.697 volts.

In my OPINION a 12 awg would most likely be all that's needed. 12/3 cords can be purchased for this use. In my experience, you'd play hell trying to find a 10/3 cable with 120v 15a plugs already attached. You'd have to make this one up. Also, trying to cram a 10 awg wire into the physical space alloted by the manufacturer of the plugs is damn near impossible. Not to mention trying to get the cord to fit through the back of the shell.

Again, these figures are only valid with a 7 amp load and 100 feet of cord.

Hope this helps

tony

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> That being said. I've done the calculations using 7 amps as the load, 100
> foot as the length of the cable. The voltage drop across an 18 awg wire (line
> to neutral) would be 5.915 volts, across a 16 awg cord 3.703 volts, across a
> 14 awg cord 2.282 volts, across a 12 awg cord 1.435 volts, across a 10 awg
> cord .903 volts.

... and the reason Woody's extension cord is a bad idea: the $10 18 awg extension cord would be dissipating about 40 watts under a 7 amp load.

That's another 40 watts on the UPS, and the cord would likely be warm to the touch.

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