Re: Mains plugs for 12V DC

"kreed"

The other problem with his system is that Mains fittings are clearly
labelled "AC ONLY" and are probably not designed to be used with 10A
DC, especially if there are switches involved.

** The  "AC ONLY" prohibition relates to use with a 240 volt DC circuit -
where arcing is a MAJOR hazard.

Generally, if a switch will reliably break 240 volts AC at some amp rating,
it will also be OK at 12 volts DC and probably 24 volts DC at that same max
current.  Nearly all switches and relay contacts have such dual ratings.

However, if like mains plugs and switches, the metal parts are made of
un-plated brass, then they cannot be relied on to *make* in a circuit at low
voltages like 12 volts.

.....   Phil

Yes, got quite a shock seeing that,  however in times gone by I have
seen mains fittings used for car to trailer connectors, as connectors
for "slot car" hand controllers (for public use) in an amusement
centre, and even as speaker connectors when I was in school (cant
remember if it was the 240 type or the 2 pin US type). Fortunately now
there are many more "correct" low voltage plugs and sockets available
to the hobbyist via Auto suppliers, dick smith and similar stores,
this probably wasn't the case prior to the 1970s, and people would use
what was commonly available - household fittings.

I can only assume that SC did this in order to provide an example of
HOW NOT to do something.

If he ABSOLUTELY HAD TO use this system, he should have at least used
the neutral and earth as the + and - connectors, and sawn off the
active pin.  At least then, there would be much less risk of danger if
it was plugged into a 240v socket mistakenly.

The other problem with his system is that Mains fittings are clearly
labelled "AC ONLY" and are probably not designed to be used with 10A
DC, especially if there are switches involved.  You are also limited
to 10amps (via the CB in the power board he used) which kind of
defeats the purpose a bit if you want to connect higher current
equipment.

SC should have pointed out that for low voltage use, (32v lighting
plants?) there is a plug and socket available - similar to the 240v
unit, but with the pins arranged in a " T " configuration.  Dick smith
had these, and no doubt Haymans etc would be able to get them for
you.

Alternately, go to Super Cheap or Autobarn, and check out the
connectors etc that they use for the high wattage sound system
installs. These would be far superior in current handling to any mains
plugs.

Also this Reminded me of another article in either EA or ETI some 25
years back showing where some fool had decided to convert his Telecom
phone system to a mains plug and socket arrangement so he could carry
the phone around his house and plug it in anywhere he wanted.  (at
that time it probably was near impossible to buy the proper "Telecom"
type sockets for the average hobbyist?)

Check out this months SC.
Someone has mailed in showing off a 12V power plug system for their
bench - using mains power plugs on all the 12V gear. And he hopes the
idea catches on!

I don't know what's sillier, the idea itself, or SC for actually
publishing it (even with the hammering and warning).

Dave.