In article ,
RadioGuy wrote:

When I first got the 'Powerpole' connectors about a year ago and played with
them something odd about them caught my attention but I could not explain
why. A couple of days ago while making connections I discovered that the
'genderless' capabilities of the connector allowed them to be connected
side-to-side, in otherwords, red-to-black, or black-to-red.

True 'nuff. If you do this, and also have a secondary ground path
present (e.g. through the antenna system), bad things could occur.

The chances of this can be reduced by:

- Not trying to plug 'em together by touch alone.

- Pick a standard orientation (most ARES groups have standardized on
a "Red on the right, when looking into the connector, contact
tongues are on the top" orientation).

- Assemble the connectors in advance of need.

- Secure the red and black connectors together after slip-fitting them,
so that they can't come apart and be reconnected incorrectly.
Anderson provides "roll pins" for this purpose, to lock 'em
together, but I've heard some people say that these can vibrate out
of the connectors. I prefer to use a drop of Crazy Glue or acetone
to permanently bond 'em together.

The possibility
of making a direct short to ground---especially from an automotive battery
exists (grounded chassis/negative ground)! Using the 'Powerpole' connectors
makes it imperative that fuses be inserted inline, not only with the battery
positive terminal as is common practice, but ideally with both sides of the
power leads on the equipment side.

Good advice!

Whenever I build equipment for 12-volt plug-in use, I prefer to stick
a reverse-polarity diode across the line, right after the equipment's
main 12-volt fuse. During normal operation there's no current flow in
the diode and no voltage drop (unlike what a forward-biased diode in
series with the line would cause). If the equipment is accidentally
hooked up with polarity reversed, the diode clamps the reverse voltage
and the fuse blows instantly, almost entirely eliminating the risk of
damage to the equipment.

I won't change back to the Amphenol connectors; I'll stay with the
'Powerpole' connectors, but it sure makes them an awkward solution and
'Hammy' way of doing things that require a bit of care when using
them---especially under emergency conditions.

You raise a valid point. I have yet to hear of this actually
happening in practice, but it's certainly possible.

I'm told that the underwater-diving industry has been using PowerPole
connectors for years - a local diver who became a ham last year was
overjoyed to finally learn how and where to get "diving light"
connectors at a reasonable (non-dive-shop) price. I'll have to ask
him whether he knows of any such accidental-reverse-hookup problems in
that industry.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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