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Re: Vegas pole pigs can't take the heat (fwd)

---------- Forwarded message ----------
Date: Sat, 07 Jul 2007 18:06:33 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>, tesla@xxxxxxxxxx
Subject: Re: Vegas pole pigs can't take the heat (fwd)

At 09:00 AM 7/7/2007, Tesla list wrote:

>---------- Forwarded message ----------
>Date: Fri, 6 Jul 2007 15:23:09 -0700 (PDT)
>From: G Hunter <dogbrain_39560@xxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: Vegas pole pigs can't take the heat (fwd)
>This is a puzzle.  I'm no engineer, but I think pole
>transformers are protected from overload by a
>"blowout" fuse or a mechanical recloser.  If too many
>customers switch on the AC, why don't these protect
>the transformer from excessive current?

Not usually.. the fusing/reclosers are used for "faults" (e.g. the 
10kA current resulting from the arc from line to ground)..

For the run of the mill overload they just gamble on statistics.. how 
much does it cost to replace the transformer, how much is the load, 
what's the temperature outside.

Aggravated by the average power consumption per household going 
up.  In Los Angeles, for instance, most of the distribution 
infrastructure is 30 years or more old.  Central AC wasn't as common 
in 1970 as it is now. If all those folks retrofit....

And, aggravated by financial pressures (as detailed by Phil in 
another email).. For instance, the pad mount transformer out in front 
of my house is a 25 kVA unit, and feeds 8 houses.  Fire up all 8 
airconditioners (at 4-5kVA each) and you see there's a potential problem.