And how would you like to be responsible for "telling" them to shut
down the main switch. After doing so there will be a gigantic kick
back of voltage to all the boats tied together on the open ac mains.
The kick back will come from the fields suddenly collapsing in all
those compressors and battery chargers that are on line. Now it is
your fault that someone's equipment got fried! :)

Regards
Gary


On Tue, 15 Feb 2005 02:45:47 GMT, Larry W4CSC wrote:

I was aboard the boat at Charleston City Marina drinking an ale because we
couldn't climb the mast to put up the THIRD Raymarine 2KW radome in the
rain. Cap'n Geoffrey, Mike and I were sitting in the main cabin when a
surge protector (simple MOV unit with no magnetic breaker) exploded with a
flash through the plastic case as one of the MOVs met its match across the
marina's hot to ground. The MOV simply exploded. A boom was heard earlier
as downtown Charleston lost one or more of its main distribution
transformers.

After the MOV blew up, I noticed the battery charger had stopped reloading
the house battery monsters, even though we had quite a few 12V loads
running. Current was -8.2A on the main shunt.

I got out the DVM and measured the AC line voltage being fed to the boat.
It was only 70 VAC! I went up to the office to ask what was going on and
the darkness they were all sitting in there was pretty self-evident. They
had shut down the office AC power to protect the computers and other
equipments.

I asked them if they could shut down the marina's main AC power supply
until SCE&Gouge could bring the brownout back up to some semblance of
normal voltage. I pointed out that every piece of refridgeration on every
uninhabited boat just sitting there would be in jeopardy, their compressors
locked trying to start on half voltage. Well, Duhhh.... "We can shut down
the marina from a special switch, but have been told (by "someone" I later
found out) not to do it." It was 6PM and the head marina bureaucrats, I
suppose, were long gone, leaving the kids to run things through the night.

Hope those crappy marine A/C units with the cheap bottled compressors don't
set fire to the boats. Properly notified of the hazard, and doing nothing
to correct it even though they had the power and "switch" to do so, should
leave marina management wide open to replace whatever burns out at 70
VAC....shouldn't it?

Should we forget worrying over isolation transformers and galvanic
isolators and just run the damned boats on some 5KW computer UPSs instead?

Our boat is shutdown, tonight. The A/Cs are powerless and the brand new
fridge is running off the monster house batteries until I get there,
tomorrow. Sure glad we decided to stay aboard for a little ale in the
rain.......