Mains plugs for 12V DC

[David L. Jones]

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.

 

[Phil Allison]

"David L. Jones"

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).

** I believe it is totally illegal to use a 240 volt plug or socket for any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!

Besides being ludicrously DANGEROUS the idea will not work reliably as the
brass plug pins and female socket parts are very prone to tarnishing and
when thick enough this tarnish will fully insulate at 12 volts.

One of the reasons why the earth pin has to be nickel plated nowadays.



...... Phil

 

[Phil Allison]

"David L. Jones"
"Phil Allison"

"David L. Jones"


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).

** I believe it is totally illegal to use a 240 volt plug or socket for
any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to
his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!

When all you have is a hammer, everything looks like a nail I guess!


Besides being ludicrously DANGEROUS the idea will not work reliably as
the
brass plug pins and female socket parts are very prone to tarnishing and
when thick enough this tarnish will fully insulate at 12 volts.

Yup. Silly, dangerous, and a poor choice.

So what would other people use as a bench 12V connector for gear?
First thing that springs to mind for me would be XLR connectors. Easy
to mount a strip of those on a panel, and 16A types are readily
available. Get a 4 way type and double up on the pins.

** I have used 4 pin " CB mic " connectors ( DSE cat P1834) for a bench
PSU that outputs +/-15 volts regulated DC to connect up various audio test
items I made to run from that voltage.

Good for a couple of amps.

Nice and cheap at $ 2.49 each - even less at WES.



..... Phil

 

[Den]

"David L. Jones" <altzone@gmail.com> wrote in message
news:edefeeae-f2b9-41c2-aa65-06b4843cc7d7@v16g2000prc.googlegroups.com...

On Sep 26, 1:58 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:
"David L. Jones"



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).

** I believe it is totally illegal to use a 240 volt plug or socket for
any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to
his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!

When all you have is a hammer, everything looks like a nail I guess!

Besides being ludicrously DANGEROUS the idea will not work reliably as
the
brass plug pins and female socket parts are very prone to tarnishing and
when thick enough this tarnish will fully insulate at 12 volts.

Yup. Silly, dangerous, and a poor choice.

So what would other people use as a bench 12V connector for gear?
First thing that springs to mind for me would be XLR connectors. Easy
to mount a strip of those on a panel, and 16A types are readily
available. Get a 4 way type and double up on the pins.

Dave.

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two pins
arranged in a "T" configuration that are intended for DC applications? Maybe
my memory is faulty.

 

[Phil Allison]

"Den"

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two
pins arranged in a "T" configuration that are intended for DC
applications? Maybe my memory is faulty.

**This what you mean ?

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?searchMode=contents&first=30&skip=23&contentId=561


** 32 volt, 15 amp AC only it says.

Same issues with tarnishing if used at a lower voltage plus a NASTY arcing
issue if used for high current DC.



...... Phil

 

[Bob Parker]

On 26/09/2008 14:37 Den wrote:

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two pins
arranged in a "T" configuration that are intended for DC applications? Maybe
my memory is faulty.

I used to use those back in the 1970s. I think they're called 'ELV'
(Extra Low Voltage) connectors and are for 32V maximum if I remember
correctly.
Dunno if they're still around ... too busy to go searching.

 

[Den]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6k37r6F5s0t8U1@mid.individual.net...

"Den"

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two
pins arranged in a "T" configuration that are intended for DC
applications? Maybe my memory is faulty.


**This what you mean ?

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?searchMode=contents&first=30&skip=23&contentId=561


** 32 volt, 15 amp AC only it says.

Same issues with tarnishing if used at a lower voltage plus a NASTY
arcing issue if used for high current DC.



..... Phil

Yep those are them - also at http://tinyurl.com/4qhugc I think they were
used by Telecom in the 70s & 80s in vehicles, trucks, 4wds etc for running
accessories in the field.

 

[Mr.T]

"Den" <Invalid@someemail.com> wrote in message
news:48dc6712$0$16005$5a62ac22@per-qv1-newsreader-01.iinet.net.au...

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).

** I believe it is totally illegal to use a 240 volt plug or socket for
any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to
his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!

When all you have is a hammer, everything looks like a nail I guess!

Besides being ludicrously DANGEROUS the idea will not work reliably
as
the
brass plug pins and female socket parts are very prone to tarnishing
and
when thick enough this tarnish will fully insulate at 12 volts.

Yup. Silly, dangerous, and a poor choice.

And yet strangely all the slot car tracks 30 years ago used 240V sockets for
the 12V hand controllers.
I have no idea if the remaining ones still do.

So what would other people use as a bench 12V connector for gear?
First thing that springs to mind for me would be XLR connectors. Easy
to mount a strip of those on a panel, and 16A types are readily
available. Get a 4 way type and double up on the pins.

Most people use the car cigarette lighter plug/sockets, or the smaller
"merit" versions. Neither is ideal, but at least most people will instantly
recognise what to expect.

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two
pins
arranged in a "T" configuration that are intended for DC applications?
Maybe
my memory is faulty.

Nope, your memory is fine, that's what my enlarger (12v halogen) uses. They
were rated to 32V from memory.

MrT.

 

[Clifford Heath]

David L. Jones wrote:

So what would other people use as a bench 12V connector for gear?

A local radio ham with who I have "foxhunted" uses RCS plugs.
They're not terribly strong, but there's heaps of contact
area and they won't come unplugged by themselves. Audio gear
always has DC isolation to 12V at least, so though inadvertent
mis-connection might make some nasty noises, no smoke.

Clifford Heath.

 

[Franc Zabkar]

On Thu, 25 Sep 2008 20:22:05 -0700 (PDT), "David L. Jones"
<altzone@gmail.com> put finger to keyboard and composed:

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.

An old friend did something like that for his radio gear, only he used
DC sockets to supply 240VAC. <shrug>

He blew up at least one radio that I know of.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Franc Zabkar]

On Thu, 25 Sep 2008 20:22:05 -0700 (PDT), "David L. Jones"
<altzone@gmail.com> put finger to keyboard and composed:

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.

I remember an Iranian friend telling me that for a while Iran used the
same wall sockets for AC mains as for telephones. People would
sometimes plug a telephone into the mains. The phone would ring,
presumably at the mains frequency, and then die.

This Wikipedia article shows one plug style as CEE 7/17 Euro 2 pin:
http://en.wikipedia.org/wiki/List_of_countries_with_mains_power_plugs,_voltages_and_frequencies

This article shows that the CEE 7/16 2-pin plug was used in older
installations:
http://en.wikipedia.org/wiki/Telephone_plug

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Phil Allison]

"Franc Zabkar" <

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!

An old friend did something like that for his radio gear, only he used
DC sockets to supply 240VAC. <shrug

He blew up at least one radio that I know of.

** I'm sure I remember a story in EA magazine, maybe in the servicemen
column, about a man who used 3 pin mains plugs to connect a big woofer
cabinet to an amplifier.

One day, his wife unplugged the woofer to do the vacuuming and then ....

BIG bang - no more woof.



...... Phil

 

[David L. Jones]

On Sep 26, 1:58 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:

"David L. Jones"



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).

** I believe it is totally illegal to use a 240 volt plug or socket for any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!

When all you have is a hammer, everything looks like a nail I guess!

Besides being ludicrously DANGEROUS the idea will not work reliably as the
brass plug pins and female socket parts are very prone to tarnishing and
when thick enough this tarnish will fully insulate at 12 volts.

Yup. Silly, dangerous, and a poor choice.

So what would other people use as a bench 12V connector for gear?
First thing that springs to mind for me would be XLR connectors. Easy
to mount a strip of those on a panel, and 16A types are readily
available. Get a 4 way type and double up on the pins.

Dave.

 

[Andy]

Phil Allison wrote:

"Den"

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two
pins arranged in a "T" configuration that are intended for DC
applications? Maybe my memory is faulty.


**This what you mean ?

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?searchMode=contents&first=30&skip=23&contentId=561


** 32 volt, 15 amp AC only it says.

Same issues with tarnishing if used at a lower voltage plus a NASTY arcing
issue if used for high current DC.



..... Phil

I agree. However, this page promotes them as "Suitable for most DC
applicacations" (their
typo - not mine) and "ultra reliable". I don't think so..........

http://www.lakecomm.com.au/connectors-cable.html

Andy

 

[ian field]

"Den" <Invalid@someemail.com> wrote in message
news:48dc6a30$0$15998$5a62ac22@per-qv1-newsreader-01.iinet.net.au...

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6k37r6F5s0t8U1@mid.individual.net...

"Den"

Aren't there mains style clipsal/hpm or whatever plugs/sockets with two
pins arranged in a "T" configuration that are intended for DC
applications? Maybe my memory is faulty.


**This what you mean ?

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?searchMode=contents&first=30&skip=23&contentId=561


** 32 volt, 15 amp AC only it says.

Same issues with tarnishing if used at a lower voltage plus a NASTY
arcing issue if used for high current DC.



..... Phil



Yep those are them - also at http://tinyurl.com/4qhugc I think they were
used by Telecom in the 70s & 80s in vehicles, trucks, 4wds etc for running
accessories in the field.

In the UK, several 12V accessories I've bought recently had car cigar
lighter plugs fitted - I generally throw these plugs in a box and replace
them with alligator clips. If at some point I wanted to set up a 12V bench
distribution system, I could visit the scrapyard and recover some cigar
lighter sockets from old car dashboards, although they can probably be had
from some component suppliers. IIRC the tyre pump had a 20A fuse and the
240V inverter was something like 35A.

 

[Phil Allison]

"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

 

[Clifford Heath]

Clifford Heath wrote:

David L. Jones wrote:
So what would other people use as a bench 12V connector for gear?
A local radio ham with who I have "foxhunted" uses RCS plugs.

Ugh, that should have been "RCA" plugs, sorry.

 

[kreed]

On Sep 26, 1:22 pm, "David L. Jones" <altz...@gmail.com> wrote:

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.

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?)

 

[Mr.T]

"kreed" <kenreed1999@gmail.com> wrote in message
news:bd27deb4-5a0f-4b6b-bd56-b0fe7410fe79@a2g2000prm.googlegroups.com...

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?)

Or maybe not. The PMG once used 4 pin sockets for portable/relocateable
phones that did look similar to the standard "bakelite" mains sockets used
at the time, at least to a casual observer anyway. That was a lot more than
25 years ago however, and the Aus standard 6 pin plug/sockets have been
readily available for a lot longer than that too.

MrT.

 

[swanny]

Phil Allison wrote:

"David L. Jones"
"Phil Allison"
"David L. Jones"

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).
** I believe it is totally illegal to use a 240 volt plug or socket for
any
other purpose than as a mains connector.

Back when I was a keen model power boat racer, one of the club members
showed up at the lakeside with a new 12V starter motor fitted with a
standard 3 pin mains plug. He had also fitted a double power point to
his
tool box to allow connection to the 12 volt battery he kept inside. The
other socket allowed him to plug in a 12V fuel pump.

Thing is, the guy made his living as an electrician !!!
When all you have is a hammer, everything looks like a nail I guess!


Besides being ludicrously DANGEROUS the idea will not work reliably as
the
brass plug pins and female socket parts are very prone to tarnishing and
when thick enough this tarnish will fully insulate at 12 volts.
Yup. Silly, dangerous, and a poor choice.

So what would other people use as a bench 12V connector for gear?
First thing that springs to mind for me would be XLR connectors. Easy
to mount a strip of those on a panel, and 16A types are readily
available. Get a 4 way type and double up on the pins.


** I have used 4 pin " CB mic " connectors ( DSE cat P1834) for a bench
PSU that outputs +/-15 volts regulated DC to connect up various audio test
items I made to run from that voltage.

Good for a couple of amps.

Nice and cheap at $ 2.49 each - even less at WES.



.... Phil

Have also used 4-pin 'CB mic' plugs for exactly the same purpose and can
recommend them. Other than that there are also DC barrel connectors which are
designed for low power DC use.