AC Plug Pack (wall wart) plugs - suggestions please

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I have in mind a project that will use AC Plug Packs. For safety and  
legal reasons I can't change that, but I am troubled by the low voltage  
power plugs supplied. They are 2.1mm round plugs just like those on  
almost any DC plug Pack.

Time marches on plug packs get mixed in together and "hey this fits" and  
pzzzt... magic smoke happens to someones piece of kit.

are there suggestions for an alternative plug to use. Doesn't need to be  
polarized (of course), but something hot plug-able would be nice.

Any suggestions?

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2/09/2020 12:01 pm, david eather wrote:
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im pretty sure there are no good options, but I,m just checking

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2020-09-01 22:18, david eather wrote:
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The only vaguely common alternatives I've seen are round DIN plugs or  
3.5 mm phone plugs.  BITD modems ran off 24VAC warts with those same  
round connectors.  A D-sub might work.

Alternatively, nearly all the warts I've seen use 2.1 or 2.5 mm centre  
pins, 5.5 mm outside.  Maybe use an odd size, like this one?

<https://www.digikey.com/product-detail/en/cui-devices/PPM-2-35135-S1/102-4709-ND/9486620>

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2/09/2020 9:28 pm, Phil Hobbs wrote:
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I think they are used in Android devices.

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2020-09-02 17:45, david eather wrote:
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Sure, they're going to be used by somebody, or they wouldn't still be  
available.  The key is to make the conjunction rare.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: AC Plug Pack (wall wart) plugs - suggestions please
On 9/1/2020 7:01 PM, david eather wrote:
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So, your "wall wart" delivers AC?

Can you put a bridge just inboard of the connector and cover the
DC +, DC -, and AC cases?

[You're still at the mercy of wrong voltage rating...]

Re: AC Plug Pack (wall wart) plugs - suggestions please
david eather wrote:

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** Though possible this rarely happens.  
  
 You need to clearly label your AC pack with the name of the item it goes with and a warning that it be used with no other.

Try to make the item damage proof if used with a DC pak up to 12V.  


.....  Phil  





Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2/09/2020 12:35 pm, Phil Allison wrote:
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Sadly, I confess I have done it. An LED clock that used 5volts got it's  
own wake up call when I plugged 12 volts into it.  I really needed the  
clock and I liked it too.

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Yep, I was thinking that would be the best I could do.

Thanks

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Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2020-09-02 17:44, david eather wrote:
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That's why we standardized on +24V.  AC won't kill our boxes because of  
the unidirectional TVS, series Schottky rectifier, and polyfuse.  
However, as you go lower in voltage, your box will draw more operating  
current, so it'll require that much more fault current to switch the  
polyfuse if somebody plugs in the wrong wart.


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24V at least.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: AC Plug Pack (wall wart) plugs - suggestions please
On Thu, 3 Sep 2020 18:30:06 -0400, Phil Hobbs

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We like 24 because it's unlikely that anybody has a higher voltage
wart around, to plug in by mistake.

Of course, my new pulse generator ships with a 48v wart!


Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2020-09-03 20:29, John Larkin wrote:
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As the wise man said, "Unbreakable toys are very useful for breaking  
other toys." ;"

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: AC Plug Pack (wall wart) plugs - suggestions please
On 9/3/2020 5:29 PM, John Larkin wrote:
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Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
are powered from 48VDC.  Not likely found in residences -- but not an
assurance for commercial establishments.

Re: AC Plug Pack (wall wart) plugs - suggestions please
wrote:

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Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
stuff available for that voltage.

In the US (and I suspect everywhere), the legal dividing line between
low voltage and lines voltage is around 50 Vdc, so this is the highest
voltage one can use and not have to follow the National Electrical
Code for power line systems.  In Japan, this starts at 100 Vac, in the
US it's 120 Vac, and everywhere else it's ~240 Vac.

The Power over Ethernet voltage is 48 Vdc for this reason.  The
connector pins et al are limited to two amps, so the highest available
voltage was used.

Joe Gwinn

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 9/4/2020 10:22 AM, Joe Gwinn wrote:
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I'm not sure how much "wall-wart powered" kit like that exists (?)

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You still have to follow the NEC when routing low voltage signals;
esp network cabling.

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I think heating in the conductors is the bigger concern (not ampacity of
connector).  Note that legacy PoE only draws ~350mA.

By contrast, a bundle of LONG cables (possibly in a raceway) can
dissipate a fair bit of heat in that enclosed volume.  (you also risk
significant voltage drop "at load" at the PD)

PoE+ just makes things worse.  And 4PPoE is just insane!!  :-/
(Sheesh!  Why not power your *TV* over the network?  Or, charge your
electric vehicle??  :> )

Re: AC Plug Pack (wall wart) plugs - suggestions please
On Friday, September 4, 2020 at 11:47:23 AM UTC-7, Don Y wrote:
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There's a fair amount of switches that are intended to power small items
(cameras, WiFi hotspots, IOT debris) and those generally use, not a wall tumor,
but a boa-digesting-a-sheep style 48V brick.

Ideally, this is -48V (the case ground is positive)
One lineup:
<https://www.netgear.com/business/products/switches/

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 9/4/2020 12:05 PM, whit3rd wrote:
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Most switches seem designed to power phones -- ~7W PDs.  And, often
not a PD per port (but some subset of that).  Often an external power
supply can augment the power available to the PSE.  But, these are
usually via "nonstandardized" connectors (certainly not a barrel connector)

E.g., a 48 port PSE would need ~700W of PSE capacity just for "nominal" PDs.
(half that if just dealing with phones; half of THAT if only supporting a
subset of phone ports!)

I've not seen an external power supply larger than a single PSE's
capacity, though (all of my APs can be configured for midspan injectors
or *direct* connection of the wall wart to the AP -- a barrel connector
in each case).  IME (YMMV), any supply that would handle multiple PDs
was integrated into the switch and powered from the mains.

My (~2KW) switch's design is powered from 48VDC -- but, as a hack!
This lets me use the battery in my UPS directly to power the switch
(instead of converting to 120VAC and then back to 48VDC) as well as
sourcing power from a 48V solar panel.

Not "listed" kit, though!  :>

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Re: AC Plug Pack (wall wart) plugs - suggestions please
On 5/09/2020 3:22 am, Joe Gwinn wrote:
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in OZ it was (is?) 32 VAC, 110 VDC

Re: AC Plug Pack (wall wart) plugs - suggestions please
wrote:

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In most standards (including IEC) the dividing line between ELV (Extra
Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
standards use 60 Vdc, some 75 V and some 120 V (+/-60 V).  

The DC limit must include peak ripple voltage. A 60 V battery voltage
should not be used, since the charging voltage would be over 60 V. For
this reason, typically 48 V (nominal) is the highest battery voltage
used.
  

Re: AC Plug Pack (wall wart) plugs - suggestions please
On Saturday, 5 September 2020 07:50:00 UTC+1, snipped-for-privacy@downunder.com  wrote:
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Some of the Netgear POE+ switches use a dc power supply rated at 54V.

John

Re: AC Plug Pack (wall wart) plugs - suggestions please
On 2020-09-05 02:49, snipped-for-privacy@downunder.com wrote:
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The standards have all changed, so that they focus on the available  
energy.  The SELV exemption has gone away and been replaced by something  
much more complicated.

(I looked into it a little bit a couple of years ago but didn't need to  
become acquainted with most of the details.)

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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