Lockable Disconnect [RE-wrenches]

[wstahle at slonet.org]

> REenchers,

Please allow me to disagree with all the fuss about the "unecessary"
lockable disconnect in a grid tied system.

First off,  the argument that the inverter is failsafe because it has
redundant safety circutry sounds like the same argument the utility uses
to justify nuclear power plants.  Also the fact that one has not failed
yet,  does not prove that one can't fail.  Inverters are complex
electronic devices and like nuke plants, it is the folks who design,
build, sell, and profit from them who extoll their infalibility.


> ..... every mains panel I have ever seen also has a place for a lock
> at the bottom to prevent opening the cover... it would be oh so easy
> for the power company to slip their special lock into this to prevent
> the system owner from turning the inverter 2 way feed circuit breaker
> ON again. Just how does this differ from a lockable disconnect??



Secondly, if we agree that safety of the workman is a prime
consideration,  and that having a disconnect means is a reasonable
condition of intertie,  then we can also assume that the lineman might
use it to disconnect an alternate source of power.  Now as more systems
go online that could add up to a lot of disconnect and reconnect time
before and after the line work.  Now why would a utility want to lock a
customer out of their own breaker panel and to the other circuts therin
while still in use, when they can simply require you to have an external
and idiot proof lockable disconnect that provides them and the lineman
true failsafe protection from backfeed.

Some of you argue that disconnects are unecessary.  Well the utilities
seem to think that grid tied is is unecessary.  Given the the costs of
the systems in question, it seems a small price to pay for the peace of
mind to the lineman and utility.

There are bigger battles to fight in the war of the public grid (commons
?). This is not one to spend your energy on.  The disconnect is a simple
cheap safety valve.  Get used to it.

Respectfully,  Wallace Stahle



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