| Author |
Message |
Allan Adler
Guest
|
 Posted:
Mon Jan 17, 2005 12:32 pm Post subject:
grounding |
|
|
I have a device that comes with an AC adaptor, with the following description
(whatever it all means):
AC ADAPTOR
CORD CONNECTED CLASS 2 POWER UNITS
MODEL: TEAD-57-122000U
INPUT: 120VAC 60Hz 36W
OUTPUT: 12VDC 2A
UL LISTED 4G38 E159614(T)
Then some diagram and MADE IN CHINA.
To me, it looks like a perfectly ordinary 2-prong adaptor. The instructions
for the device that uses it (a shop machine with motors that run off the
adaptor) say that it is important to ground it and that one needs to purchase
a 3-prong adaptor and shows pictures of how it fits into a 3-prong wall socket.
I've done that in the past when I've connected stuff directly to wall sockets.
There is usually a screw or something that one can use to connect a lead
coming out of the 3-prong adaptor. However, at the moment, I want to
plug it into a power strip and there is nothing to connect the lead
wire to. So I'm not sure what to do.
Normally I wouldn't worry about it. I would just plug the 2 prong adaptor
into the power strip and forget about the third hold. But I'm trying to
do this as carefully as possible, including confronting possibly unnecessary
details that might turn out to matter. So, with apologies in advance for
what is undoubtedly the dumbest question of the new year so far, can someone
please explain how to make sure the thing is properly grounded under these
circumstances?
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
|
|
| Back to top |
|
 |
Jamie
Guest
|
| Posted:
Tue Jan 18, 2005 2:13 am Post subject:
Re: grounding |
|
|
Allan Adler wrote:
| Quote: | I have a device that comes with an AC adaptor, with the following description
(whatever it all means):
AC ADAPTOR
CORD CONNECTED CLASS 2 POWER UNITS
MODEL: TEAD-57-122000U
INPUT: 120VAC 60Hz 36W
OUTPUT: 12VDC 2A
UL LISTED 4G38 E159614(T)
Then some diagram and MADE IN CHINA.
To me, it looks like a perfectly ordinary 2-prong adaptor. The instructions
for the device that uses it (a shop machine with motors that run off the
adaptor) say that it is important to ground it and that one needs to purchase
a 3-prong adaptor and shows pictures of how it fits into a 3-prong wall socket.
I've done that in the past when I've connected stuff directly to wall sockets.
There is usually a screw or something that one can use to connect a lead
coming out of the 3-prong adaptor. However, at the moment, I want to
plug it into a power strip and there is nothing to connect the lead
wire to. So I'm not sure what to do.
Normally I wouldn't worry about it. I would just plug the 2 prong adaptor
into the power strip and forget about the third hold. But I'm trying to
do this as carefully as possible, including confronting possibly unnecessary
details that might turn out to matter. So, with apologies in advance for
what is undoubtedly the dumbest question of the new year so far, can someone
please explain how to make sure the thing is properly grounded under these
circumstances?
just use a water pipe, screw on the outlet box etc and connect it |
directly to the metal case of the equipment. |
|
| Back to top |
|
|
Allan Adler
Guest
|
| Posted:
Wed Jan 19, 2005 12:37 am Post subject:
Re: grounding |
|
|
Let me try to state the problem again a little more simply. I have an
AC adaptor from 120VAC to 12VDC. It has two prongs. The manual says
it has to be properly grounded using a 2-prong to 3-prong adaptor.
I don't think that makes any sense. I just don't see what anything one
does with a 2-prong to 3-prong adaptor has to do with the electrical state
of the AC adaptor or the devices that it powers.
Here is exactly what the manual says: "GROUND THIS PRODUCT: The 12 Volt
Transformer for this product is equipped with a 2-prong Plug and requires
the use of a grounded, 3-Prong Adapter Plug (not included). To comply with
the National Electric Code, and to provide additional protection from the
risk of electrical shock, this product should not only be connected to a
120 Volt, 3-hole electrical outlet that is protected by a Ground Fault
Circuit Interrupter (GFCI). (See Figure A.)".
Figure A shows the 2-prong plug being plugged into a typical 3-prong
adaptor plug which is in turn being plugged into a 120 volt, grounded
electrical outlet.
What does one need the 3-prong adaptor for? A 2-prong plug will plug
into a 3-prong hole and the 3-prong adaptor seems to have nothing to
do with what is happening electrically with the transformer?
If they had sent me a device with a 3-prong plug and I only had a 2-prong
hole in the wall socket, then some kind of adaptor that let me plug a
3-prong plug into the wall socket and included a way to ground it might
make sense.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
|
|
| Back to top |
|
|
Richard
Guest
|
| Posted:
Wed Jan 19, 2005 7:28 pm Post subject:
Re: grounding |
|
|
Allan Adler wrote:
| Quote: | Let me try to state the problem again a little more simply. I have an
AC adaptor from 120VAC to 12VDC. It has two prongs. The manual says
it has to be properly grounded using a 2-prong to 3-prong adaptor.
|
That sounds like "boilerplate", sometimes inappropriate, lawyer-driven,
statements that are stuck on all products. It doesn't seem to have any
applicabilty to your device. If you are a worrier just ground the damn
machine and get on with it.
Richard |
|
| Back to top |
|
|
Allan Adler
Guest
|
| Posted:
Wed Jan 19, 2005 10:50 pm Post subject:
Re: grounding |
|
|
"Richard" <beezoboar@hotmail.com> writes:
| Quote: | That sounds like "boilerplate", sometimes inappropriate, lawyer-driven,
statements that are stuck on all products. It doesn't seem to have any
applicabilty to your device.
|
That was also my impression. Thanks for confirming it.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston. |
|
| Back to top |
|
|
me
Guest
|
| Posted:
Thu Jan 20, 2005 12:45 pm Post subject:
Re: grounding |
|
|
"Richard" <beezoboar@hotmail.com> wrote in news:1106141298.145970.263580
@z14g2000cwz.googlegroups.com:
| Quote: |
Allan Adler wrote:
Let me try to state the problem again a little more simply. I have an
AC adaptor from 120VAC to 12VDC. It has two prongs. The manual says
it has to be properly grounded using a 2-prong to 3-prong adaptor.
That sounds like "boilerplate", sometimes inappropriate, lawyer-driven,
statements that are stuck on all products. It doesn't seem to have any
applicabilty to your device. If you are a worrier just ground the damn
machine and get on with it.
Richard
|
what were you doing reading the manual???? |
|
| Back to top |
|
|
Guest
|
| Posted:
Thu Jan 20, 2005 9:03 pm Post subject:
Re: grounding |
|
|
Allan Adler wrote:
| Quote: | What does one need the 3-prong adaptor for?
A 2-prong plug will plug into a 3-prong hole ...
|
Better yet, next time you're in Home Depot or wherever, see if such an
adapter is even available! There is no reason for anyone to even make
such a thing.
Richard is right, it sounds like some legal-driven requirement. If it
really required grounding, they would need to make it with a grounding
prong. |
|
| Back to top |
|
|
Allan Adler
Guest
|
| Posted:
Mon Jan 24, 2005 10:53 pm Post subject:
Re: grounding |
|
|
me <me@here.net> writes:
| Quote: | what were you doing reading the manual????
|
It's an old habit from using learning programming languages. I tried
to quit a couple of times, but it's really tough.
In this case, the device is an 8-in-3 multipurpose machine from
Harbor Freight, model 40102.
http://www.harborfreight.com
It arrives in a (cardboard box containing a) styrofoam box and is nearly
completely disassembled into almost 100 types of parts and this astonishingly
misleading manual is the only clue you get on how to put them together.
Some parts seem to be mislabeled and at least one part number seems
not to be represented. There is an exploded diagram of the box and
its contents in the manual, but due to aliasing errors, it is almost
impossible to use it to identify anything. Thus, even determining which
part numbers are represented has been a major undertaking.
On the other hand, it costs $200 (including S&H), which is cheap compared
with what lathes and milling machines cost, and even though it is clearly
just a toy, I think I'll be happy with it if I can just get it to work.
I've put together the jig saw and the wood lathe, but some details
of the metal lathe have me stumped, and there are several other
machines I still haven't built from the kit.
The main problem with the metal lathe is making sense of how one attaches
the tool to the cross slide. Otherwise, it is completely built.
In spite of these difficulties, I'm finding the experience pretty educational.
I can't post to rec.crafts.metalworking about it because:
(1) I am undoubtedly the only person on the group who has ever demeaned himself
to such an extent as to use this toy, hence people will be asking me about
it rather than the other way around.
(2) I promised that I wouldn't post to the group until I had built something,
however small or crappy. It seems that the long discussions I was having
in the hopes of getting a better set of inexpensive machine tools
provoked some judgmental heckling that made it necessary for me to
prove I was really interested in doing some metalworking. So, I'm
proving it. This is no reflection on rcm, which I think is one of
the best newsgroups in USENET by practically every standard I can
apply, and I'm looking forward to getting active in it again.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston. |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in