Re: Power

["William Graves" <graves-at-xxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Tesla list wrote:

> Original poster: "J. B. Weazle McCreath" <weazle-at-hurontel.on.ca>
>
> At 06:23 PM 15/11/00 -0700, you wrote:
> >Original poster: "Jason Johnson" <hvjjohnson13-at-hotmail-dot-com>
> >
> >I'm running a 240 volt, 40 amp dedicated line out to my "High voltage
> >Laboratory" (garage really).  Will 6 guage copper handle this power?
> >
>
> Number 6 will easily handle 40 amps.  I'd go with a run of 8/3 myself
> so that you could have both 120 and 240 available via a garage subpanel.
>
> >Also, I noticed that all the power comes into our house through a 5 KVA
> >pole pig, and two 16/3 cables with the conductors parelleled.  I will
> >be using twice that amount of power in the garage alone!  How can that
> >be up to code!?   Should the question be "Will the point where I tie
> >into the grid handle that power?"  instead of "Will MY wiring handle it?"
>
> Whoa!  Something's not right there!!  I think you best have an electrician
> take a look at your service before doing anything.  For one thing, unless
> your power usage in the house is just for lights, I don't see how the 16/3
> has not burned up!!  I use a moderate amount of power here, about 25 KWH a
> day, and my home is powered from a dedicated 25 KVA pig with 4/0 conductors
> running into the service panel!  Be safe and get it checked out.
>
> 73, Weazle, VE3EAR/VE3WZL
>
> Listening: 147.030+ and 442.075+
> E-mail:    weazle-at-hurontel.on.ca
>            or ve3ear-at-rac.ca
> Web site:  www.hurontel.on.ca/~weazle

Well, the NEC has lots of different tables on ampacity, depending on what sort
of conductor you propose to use and exactly what voltage drop you are willing
to tolerate and exactly how hot the conductors are permitted to get and if they
are copper or aluminum.  However, number 6 is pretty safe at 50 amps, all other
things being normal.  On the other hand, 50 amps times 240 volts is 12 KVA,
give or take a square root of 2.  Forty amps times 240 volts is 9.6 KVA, give
or take a factor of square root of 2.  It would seem that perhaps you may be
blowing your house main breaker on a regular basis, if you are indeed using all
of the amperage permitted by the laboratory conductors.  Perhaps you may wish
to turn off your lamps and your refrigerator before activating your coil.

On the other hand, what the heck!

    Best regards,
    Bill Graves