[aprssig] Shack backup power

Lee Mushel herbert3 at centurytel.net
Sat Jun 4 19:14:25 EDT 2011


I sense there is some confused thinking here.  When I installed my automatic 
generator backup system I immediately talked to the foreman of the 
maintenance crew that serves my area.   I told him that while I had a proper 
transfer switch (to disconnect me from the "grid" when my generator operates 
since there is an obvious chance for me to power the utility lines while 
they might be serviced--a very serious safety and legal issue) I still felt 
that there was always a chance that I might accidentally attempt to supply 
power to their lines.   They told me to not worry, they were always very 
careful and that if work was being done the line would be securely grounded. 
My generator would see an effective short circuit.   And there is also law 
that says you cannot simply power the grid.   If you want to be paid for the 
power you generate then an "approved system" would have to be used.

In the case being discussed here you will have to consider what happens to 
the connection to the grid in the event of a power interruption.   I am 
forced to assume that the "plug in grid tie inverters" you are talking about 
will automatically shut down.   Thus you are not talking about a situation 
that would provide emergency power unless, as has been proposed in some 
notes in this thread, you have created an independent battery-based system.

I think it's unfair to leave someone who knows little about this topic, with 
the impression that "there's nothing to it!"  There are complex issues and 
considerable expense associated with a system of sufficient capacity to do 
"real work" like start a compressor or a well pump.


Lee  K9WRU
----- Original Message ----- 
From: "Bob Bruninga " <bruninga at usna.edu>
To: "TAPR APRS Mailing List" <aprssig at tapr.org>
Sent: Saturday, June 04, 2011 2:58 PM
Subject: Re: [aprssig] Shack backup power

>>> ...With these small plug-in grid-tie inverters
>>> in the 250 Watt class, now it is possible to run our shack:
>> Do you have a reference for these plug-in grid-tie
>> inverters?  I can not possibly see how these would
>> be legal but I want to see the manufacturer's
>> website if they exist.

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