Advice for converting Sears Craftsman 220V compressor plug to washing machine plug
Elmo
Details:
1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
plug with one blade sideways (otherwise it looks like a normal 120V
grounded plug).
2. I have no sockets in the house which fit that 220 volt plug.
3. I have a three-pronged dryer socket in the garage with 220 volts (two
hots and a neutral).
4. I just attached a new 3-pronged male dryer cord to a female 220 volt
plug with the one blade sideways.
Before I plug in the compressor to the recepticle to the dryer cord to the
recepticle, would you have any concerns about safety or other?
I assumed the neutral in the compressor plug was the center wire (looks
like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
is the L-shaped center pin. Is that the correct assumption for the shared
neutral?
Evan
Ummm yeah... Why would you want to plug a 20 amp 240 volt appliance
which uses a NEMA 6-20 cord configuration into a 30 amp outlet made
for
a NEMA 10-30 cord configuration by means of using a cord adapter which
you have created yourself...
There is a reason why the outlets for vastly different amperage
ratings do
not fit into each other... SAFETY...
Why not have a correct 20 amp 240 volt NEMA 6-20 outlet installed in
your
home so you can use your compressor safely on a circuit which is not
capable of supplying more power than your appliance is rated for which
could damage it or cause an accident of some kind...
~~ Evan
mm
<dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
>I just want advice for the conversion I just did before I plug it all in.
>
>Details:
>1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
>plug with one blade sideways (otherwise it looks like a normal 120V
>grounded plug).
>
>2. I have no sockets in the house which fit that 220 volt plug.
>
>3. I have a three-pronged dryer socket in the garage with 220 volts (two
>hots and a neutral).
>
>4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>plug with the one blade sideways.
>
>Before I plug in the compressor to the recepticle to the dryer cord to the
>recepticle,
Huh?
> would you have any concerns about safety or other?
>
>I assumed the neutral in the compressor plug was the center wire (looks
>like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>is the L-shaped center pin. Is that the correct assumption for the shared
>neutral?
Instead of assuming such things, why not get a meter that measures
resistance and figure out whicih wire goes to which prong in each
cord? Hint: There is no neutral in a 220 volt appliance or its cord.
Two wires will be hot relative to ground and the ground wire should
not be connected to the other two.
Also get a meter that goes up to 250 VAC and measure the voltage at
all three slots of the receptacle, relative to ground. Then you'll
know which 2 slos are hot, and which two prongs of the cord will be
hot, when connected to the appliance, and which need to be connected
to each other electrically (in the appliance).
This is not to say I think the project is a good idea. No comment on
that.
Smitty Two
Elmo <dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
> I have a two-phase 220V Sears Craftsman compressor
Really? Two phase? How old is this gadget, anyway?
Bill
>I just want advice for the conversion I just did before I plug it all in.
>
> Details:
> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220
> volt
> plug with one blade sideways (otherwise it looks like a normal 120V
> grounded plug).
>
> 2. I have no sockets in the house which fit that 220 volt plug.
>
> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
> hots and a neutral).
>
> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
> plug with the one blade sideways.
>
> Before I plug in the compressor to the recepticle to the dryer cord to the
> recepticle, would you have any concerns about safety or other?
>
I've seen thousands of dollars of damage done from people replacing plugs
and not realizing what they are doing....
Have the proper outlet, wiring, and circuit breaker installed!
Jon Danniken
>
> Why not have a correct 20 amp 240 volt NEMA 6-20 outlet installed in
> your
> home so you can use your compressor safely on a circuit which is not
> capable of supplying more power than your appliance is rated for which
> could damage it or cause an accident of some kind...
Nonsense. I have a lamp here which states not to use more than a 100 watt
bulb, and uses an 18 gauge cord.
It plugs into a 15A receptacle, fed by a 14 gauge wire.
All of this is perfectly to code.
Jon
jamesgangnc
Address.invalid> wrote:
Yes, the L shaped prong is the nuetral on a 3 wire dryer. The other
two are the hots. Your compressor more likely needs 2 hots and a
ground. While what you are doing is not exactly by the book it will
run your compressor. The safety issue is that you will be using your
nuetral line for a ground and using a 30 amp circuit where a 20 amp
one is called for. What you really need to do is install a dedicated
220 outlet in the location of your compressor. Have you looked at the
compressor to see if it can be run on 110? Many motors have alternate
wiring that allows them to run on 220 or 110.
Jon Danniken
> I just want advice for the conversion I just did before I plug it all
> in.
>
> Details:
> 1. I have a two-phase 220V Sears Craftsman compressor which uses a
> 220 volt plug with one blade sideways (otherwise it looks like a
> normal 120V grounded plug).
>
> 2. I have no sockets in the house which fit that 220 volt plug.
>
> 3. I have a three-pronged dryer socket in the garage with 220 volts
> (two hots and a neutral).
>
> 4. I just attached a new 3-pronged male dryer cord to a female 220
> volt plug with the one blade sideways.
>
> Before I plug in the compressor to the recepticle to the dryer cord
> to the recepticle, would you have any concerns about safety or other?
Yes. Find out if your compressor expects the third terminal to be a ground;
the third wire on your dryer is likely a neutral. If such is the case, you
will need to install a properly grounded outlet for your compressor.
As to sharing the receptacle between a dryer and a compressor, I have done
that with a welder, and to be honest, it gets old really fast. Eventually,
you will want to install a dedicated circuit, and the sooner the better.
Jon
George
I don't believe you will find a code reference that allows what the OP
described since your example doesn't scale.
RBM
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in message
news:i2gk9k$pb1$1...@tioat.net...
Your setup will work as you describe. The Nec prohibits using a 20 amp
receptacle on a 30 amp circuit.
Provided that the motor has built in overcurrent protection, I would install
a 30 amp dryer cord set directly on the compressor
RBM
"Jon Danniken" <jonSPAMMEN...@yahSPAMhoo.com> wrote in message
news:i2hbnl$fib$1...@speranza.aioe.org...
> Elmo wrote:
>> I just want advice for the conversion I just did before I plug it all
>> in.
>>
>> Details:
>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a
>> 220 volt plug with one blade sideways (otherwise it looks like a
>> normal 120V grounded plug).
>>
>> 2. I have no sockets in the house which fit that 220 volt plug.
>>
>> 3. I have a three-pronged dryer socket in the garage with 220 volts
>> (two hots and a neutral).
>>
>> 4. I just attached a new 3-pronged male dryer cord to a female 220
>> volt plug with the one blade sideways.
>>
>> Before I plug in the compressor to the recepticle to the dryer cord
>> to the recepticle, would you have any concerns about safety or other?
>
> Yes. Find out if your compressor expects the third terminal to be a
> ground; the third wire on your dryer is likely a neutral. If such is the
> case, you will need to install a properly grounded outlet for your
> compressor.
The third terminal on a three wire dryer outlet is a neutral/ground, and by
code must original in the main service panel and not a sub panel
Elmo
On Sun, 25 Jul 2010 00:36:55 -0700 (PDT), Evan wrote:
> Why not have a correct 20 amp 240 volt NEMA 6-20 outlet installed in
> appliance is rated for
I agree with Evan, the right way to power the compressor with the NEMA
6-20P plug (20amp rating), is to hire an electrician to add a dedicated
220V NEMA 6-20R receptacle with a 30 amp dedicated circuit breaker.
Or to have that electrician swap out the existing NEMA 6-20R with a NEMA
6-20R and to swap out the 30 amp breaker with one with only a 20 amp
rating.
However, the cost of hiring the electrician to change the circuit is more
than that of buying a new compressor with, say, standard 110 volt power.
I use the compressor maybe once every six months. Unknowns in the adapter
setup are what I'm asking about here.
The unknowns to overcome by asking this post are:
a) How do I test if the NEMA10-30R is on a sub panel or not?
b) Did I select the right pin ground in the NEMA 6-20R receptacle as the
L-shaped neutral in the NEMA10-30P plug?
Elmo
> Also get a meter that goes up to 250 VAC and measure the voltage at
> all three slots of the receptacle, relative to ground.
I did use the Fluke DMM to measure the connections; I was just double
checking which was the ground/neutral because I didn't wire the house in
the first place.
The ground in the two-phase 220v compressor NEMA 6-20P plug should be the
center pin and the ground/neutral in the NEMA10-30R dryer receptacle should
be the L-shaped center prong.
The two questions I would like to ask here are:
a) How do I know if the NEMA10-30R is on a sub panel (it's inches from the
main panel on the other side of the wall outside the garage)?
b) Are my tests correct that the ground on the 20-amp NEMA 6-20P plug is
"equivalent" to the ground/neutral on the 30-amp NEMA10-30R receptacle?
Steve Barker
I'm suspecting that out of all these replies, NONE are correct. What i
suspect is that you have a 20a plug on a 120V compressor and you just
don't have any 20a 120v outlets in your house. Better look a little
closer at everything before you feed that unit 240v.
--
Steve Barker
remove the "not" from my address to email
Elmo
> Really? Two phase? How old is this gadget, anyway?
You know, I bought it that damn Sears Craftsman compressor on a whim in a
sale in the 80's. It was (on sale), about 350 or 400 bucks.
Then, when I brought the huge thing home, I realized I didn't have an
outlet for it, so I just let it sit for a year or so. Then I moved, and
didn't have an outlet for it, so I let it sit for a few years. Finally I
moved to a place that had the outlet, and I used it every six months or so
to blow up the kids toys. I moved again, and guess what, no outlet.
Funny thing is that I've seen Sears compressors on sale over and over and
over and over again for, guess what, just about 350 or 400 bucks. They
never changed prices in decades. Amazing.
In hind sight, I never should have bought it as I barely used it due to the
cord and the lack of needs.
However, I still have it. And I actually want to blow up a kids toy and
then figured I'd plug the NEMA 6-20P into an adaptor consisting of a NEMA
6-20R and a NEMA10-30P and then connect to the NEMA10-30R fused by a 30-amp
circuit for my 20-amp compressor.
I was just asking advice, specifically:
a) How do I know that I'm NOT on a sub panel?
b) Did I pick the correct ground/neutral?
Is there anything else I didn't think of (before I plug it in)?
Steve Barker
Elmo
> Have the proper outlet, wiring, and circuit breaker installed!
Let's look at this from a "safety" standpoint, which is your point.
The "proper" way to do this, all will agree, is to spend more than the
compressor is worth to install a 20-amp dedicated NEMA 6-20R receptacle.
However, from a safety standpoint, if anyone can show me how plugging the
20-amp NEMA 6-20P through an adapter to the 30-amp NEMA10-30P receptacle is
inherently more dangerous, then I'll listen.
Of course, I do realize that the "equipment" won't be protected to 20 amps
(it will be protected to 30 amps); but I'm not at all worried about the
30-year old compressor burning up.
The "house" wiring is still protected to 30 amps, which is what matters.
And "safety" is the same (as far as I can tell) since we're using exactly
the same two hots and the same ground/neutral.
Or did I miss something critical in that analysis?
Advice always welcome.
Steve Barker
Here's a better comparison, scroll down to the 20a section. It seems it
could be a 120v OR a 240v depending on which side the sideways blade is on.
http://www.frentzandsons.com/Hardware%20References/plugandreceptacleconfiguratio.htm
RBM
"Steve Barker" <ichase...@notgmail.com> wrote in message
news:EvWdnWAEdY8fodHR...@giganews.com...
Very good point. Most of these small compressors run 120 or 240 volts, and
do require a 20 amp plug @120 volt. It is entirely probable that the OP is
looking at a 20 amp 120 volt plug and not a 20 amp 240 volt plug, which are
very similar looking
Elmo
> What you really need to do is install a dedicated 220 outlet
I agree that's the by-the-book method. However, the cost of having an
electrician replace the 30-amp NEMA 10-30R with a 20-amp NEMA 6-20R is more
than the cost of a compressor that runs off of 110.
> Have you looked at the compressor to see if it can be run on 110?
I didn't realize the 30-year old Sears Craftsman compressor COULD run on
110. How would I know? (I'll try to dig up a model number and google it
after this reply.)
> The safety issue is that you will be using your nuetral line
> for a ground and using a 30 amp circuit where a 20 amp
> one is called for.
But wouldn't the neutral line ALREADY be used as a ground in the NEMA
10-30R dryer circuit were I to plug in a dryer to that circuit?
Isn't the compressor the same as the dryer from an electrical standpoint
with respect to the ground/neutral wire?
dpb
..
> Yes, the L shaped prong is the nuetral on a 3 wire dryer. The other
> two are the hots. ...
It is ground serving (per applicable Code of the time) as ground/shared
neutral.
> Your compressor more likely needs 2 hots and a
> ground. While what you are doing is not exactly by the book it will
> run your compressor.
It is _exactly_ by current book for 240V service w/ the 240V load there
is no need for the neutral; therefore the ground is no longer serving as
a shared neutral only as ground.
> The safety issue is that you will be using your
> nuetral line for a ground and using a 30 amp circuit where a 20 amp
> one is called for. What you really need to do is install a dedicated
> 220 outlet in the location of your compressor. Have you looked at the
> compressor to see if it can be run on 110? Many motors have alternate
> wiring that allows them to run on 220 or 110.
No, NO, _NO_! There is no safety issue; as above the 3rd conductor in a
shared utility (dryer) outlet _IS_ the ground conductor; the NEC
formerly allowed it to be shared function of also serving the neutral.
It is wired to the ground bus, _NOT_ the neutral.
The second misconception here is that there's some proscription against
a higher-rated circuit supply a lesser-rated load--that again is simply
nonsense. The 30A circuit breaker/fuse is there to protect the circuit,
_NOT_ the load; the load will have its own overload protection for that
purpose.
While I'll agree it's certainly a nuisance factor to have a humongous
30A dryer plug on the end of the cord for a small compressor, it is not
an issue whatsoever from a safety (or Code, for that matter) standpoint.
--
Elmo
> Find out if your compressor expects the third terminal to be a ground;
> the third wire on your dryer is likely a neutral. If such is the case, you
> will need to install a properly grounded outlet for your compressor.
Isn't a ground for the compressor NEMA 6-20P plug the same as the neutral
for the dryer NEMA 10-30R receptacle?
> As to sharing the receptacle between a dryer and a compressor
Actually, I should have mentioned, there is no sharing. There is no dryer
on this spare receptacle in the garage. The dryer is on a separate NEMA
10-30R in the house. I do agree that unplugging a dryer once every six
months to use the compressor would be a pain.
Elmo
> I don't believe you will find a code reference that allows what the OP
> described since your example doesn't scale.
I wondered about that. Does the "code" cover temperary adapters?
Doesn't the code only apply to the wiring in the walls?
This is an adapter, which is not permanently connected.
And, the wiring is the same, either way, as far as I can tell. The only
ground/neutral difference I see is the NEMA 6-20P ground for the compressor
is connected to the NEMA 10-30R ground/neutral for the dryer. But isn't
that dryer neutral connected directly to ground anyway at the panel on the
other side of the wall?
And, the 20-amp rating for the compressor is connected to a 30-amp breaker
instead of a 20-amp breaker. But, that will still protect the wiring in the
wall from 30 amp surges (it just won't protect the compressor).
Right?
dpb
...
> However, from a safety standpoint, if anyone can show me how plugging the
> 20-amp NEMA 6-20P through an adapter to the 30-amp NEMA10-30P receptacle is
> inherently more dangerous, then I'll listen.
Assuming the adapter is compliant it isn't...
> Of course, I do realize that the "equipment" won't be protected to 20 amps
> (it will be protected to 30 amps); but I'm not at all worried about the
> 30-year old compressor burning up.
The compressor motor will have it's own overload protection.
> The "house" wiring is still protected to 30 amps, which is what matters.
That's all the circuit breakers protect against for anything plugged
into them; there's no difference in the case of the dryer being plugged
into the outlet as the compressor; the internal dryer motor isn't a 30A
device by any stretch, either.
>
> And "safety" is the same (as far as I can tell) since we're using exactly
> the same two hots and the same ground/neutral.
Correct, and in fact w/ the compressor being a 240V load only, there is
no need for and no neutral current. The shared conductor is serving
only the ground function at that time, just as would the third conductor
in a 20A plug connection.
> Or did I miss something critical in that analysis?
No...the others are simply incorrect in understanding of Code and
perhaps even function of three-wire dryer circuit...
--
Ed Pawlowski
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote>
> Funny thing is that I've seen Sears compressors on sale over and over and
> over and over again for, guess what, just about 350 or 400 bucks. They
> never changed prices in decades. Amazing.
But I bet they cheapened it and now is made in China, or at least major
parts of it
Elmo
> It is entirely probable that the OP is looking at a 20 amp 120 volt plug
> and not a 20 amp 240 volt plug, which are very similar looking
It was my fault for not explaining clearly.
The plug on the compressor is a NEMA 6-20P (not a NEMA 5-20P); but I do
agree that's a great point to doublecheck.
http://www.jkem.com/pictures/NEMA%20Non-Locking%20Plugs.gif
Here's also what the plate says:
"240V 15 Amp Sears Craftsman model 919.176940".
RBM
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in message
If that's the case, why don't you just replace the breaker and receptacle
with a 20 amp
dpb
> On Sun, 25 Jul 2010 05:41:59 -0700 (PDT), jamesgangnc wrote:
>> What you really need to do is install a dedicated 220 outlet
>
> I agree that's the by-the-book method. However, the cost of having an
> electrician replace the 30-amp NEMA 10-30R with a 20-amp NEMA 6-20R is more
> than the cost of a compressor that runs off of 110.
>
>> Have you looked at the compressor to see if it can be run on 110?
> I didn't realize the 30-year old Sears Craftsman compressor COULD run on
> 110. How would I know? (I'll try to dig up a model number and google it
> after this reply.)
The motor will marked as dual-voltage if it can...wouldn't be too
surprising but I'd stick w/ 240V as you'll need double the amps for 110V
and you may well be in worse conundrum of not having a circuit w/ the
ampacity to run it on 120V...
>> The safety issue is that you will be using your nuetral line
>> for a ground and using a 30 amp circuit where a 20 amp
>> one is called for.
>
> But wouldn't the neutral line ALREADY be used as a ground in the NEMA
> 10-30R dryer circuit were I to plug in a dryer to that circuit?
There's that turning around of the actual situation on a dryer outlet
wiring again for one and the misconception regarding the point of 30A
circuit protection having anything to do w/ the load plugged into the
outlet. Both are simply wrong.
The third conductor is _NOT_ the neutral serving as ground, it is
THE_GROUND_CONDUCTOR_ sharing service as the neutral for the 120V
components in the dryer (motor/lights/timer/etc.).
For the other, the 30A breaker is there to protect the circuit wiring;
it is the responsibility of the load to have the correct protection for
itself internally.
> Isn't the compressor the same as the dryer from an electrical standpoint
> with respect to the ground/neutral wire?
For the 240V components (the heater elements) of the dryer, yes;
identically. There is no 120V load on the compressor so the need for
the sharing of ground/neutral disappears and is, therefore, fully
compliant with current NEC for 240V loads whereas the dryer would
require a four-wire connection to be compliant to current NEC. From
that standpoint, the compressor is "more correct" than the intended use
of the dryer on the circuit (that _was_ compliant w/ NEC of the time, of
course).
Again, if the adapter you're using is compliant and well made, ignore
the do-gooders' advice here--they mean well but are simply misinformed
or overly cautious or just don't understand (or maybe even all of the
above :) ).
--
Elmo
> does it look like this:
> http://tinyurl.com/2dd6t2h
:)
I do appreciate the double check (as that's what this thread is all
about!).
Check twice, plug in once! :)
You show what appears to be a NEMA 5-20P; I have the NEMA 6-20P. The
difference is (looking at the plug head on with the ground up), my sidewise
blade is on the right whereas that plug's sidewise blade is on the left.
http://www.jkem.com/pictures/NEMA%20Non-Locking%20Plugs.gif
I've had the compressor for 30 years and barely used it because of this
damn plug. If I can give any advice to a young 30 year old kid buying his
first compressor, it would be to get a 110V smaller one!
BTW, the plate on the wheeled tank says:
Sears Craftsman model 919.176940 240 volts 15 amps
Elmo
> Here's a better comparison, scroll down to the 20a section.
I like YOUR reference better than mine:
http://www.jkem.com/pictures/NEMA%20Non-Locking%20Plugs.gif
Because yours answers one of my questions, which is to doublecheck which is
the green ground wire in the NEMA 6-20P (g) to mate with the white
ground/neutral in the NEMA 10-30R (w) via the NEMA 6-20R-to-NEMA 10-30P
adapter.
Your chart has little W's and G's and "X" and "Y" for the hot black wires.
I presume the "w" stands for white, does it not?
dpb
> On Sun, 25 Jul 2010 05:46:47 -0700, Jon Danniken wrote:
>> Find out if your compressor expects the third terminal to be a ground;
>> the third wire on your dryer is likely a neutral. If such is the case, you
>> will need to install a properly grounded outlet for your compressor.
It's a ground that shares neutral function, not vice versa...
> Isn't a ground for the compressor NEMA 6-20P plug the same as the neutral
> for the dryer NEMA 10-30R receptacle?
Yes, addressed elsewhere...
>> As to sharing the receptacle between a dryer and a compressor
>
> Actually, I should have mentioned, there is no sharing. There is no dryer
> on this spare receptacle in the garage. ...
In that case, the simple (and relatively inexpensive) solution would be
to swap to a 20A breaker to support the proper 20A outlet style to plug
the compressor in directly. There's nothing wrong w/ the wiring being
_larger_ than required for the ampacity of the circuit; all it does is
mean there will be even less voltage drop than otherwise would be.
--
Elmo
> But I bet they cheapened it and now is made in China
I just googled my 30-year-old Sears Craftsman model 919.176940 and, as
expected, couldn't find it for sale new anymore to check the prices.
But, used, it's 60 bucks!
http://www.propertyroom.com/ItemDetails.aspx?l=7499498
Because of this NEMA 6-20P plug, I've almost never used the 350 or 400
dollar compressor that I bought "because it was on sale" thirty years ago
when I was just a kid.
It looks like I can still get parts for it at
http://www.searspartsdirect.com
But no manual for the 20-gallon 125psi air compressor seems to exist on the
net.
Steve Barker
yes, that's correct
dpb
...
> Because yours answers one of my questions, which is to doublecheck which is
> the green ground wire in the NEMA 6-20P (g) to mate with the white
> ground/neutral in the NEMA 10-30R (w) via the NEMA 6-20R-to-NEMA 10-30P
> adapter.
As noted elsewhere, you'd be better served to go to 20A breaker/plug and
junk the adapter, though...
> Your chart has little W's and G's and "X" and "Y" for the hot black wires.
>
> I presume the "w" stands for white, does it not?
Strictly speaking, it's "neutral"; but conventional (USA, anyway) wiring
is white for neutral, yes.
--
Elmo
> Assuming the adapter is compliant it isn't...
You seem to understand the situation the best.
The adapter is a standard metal box with the NEMA-6-20R and a three-inch
long strain relief for the dryer cord securely attached to the metal box.
The only problem I had was the dryer cord had three brass "circles" as the
connection point but the NEMA-6-20R had screws which didn't expect to be
taken out to accomodate circular connections. The last few threads removing
the screws "broke" something, as the screws are clearly designed to stay
in.
When I removed the three screws (two brass for the black wires and one
green-painted steel for the ground/neutral wire), it was hard to get them
back in.
I wondered if it was the male screw or the female hole that "stripped" when
these type of stay-in screws are removed. I guessed it was the female part
that stripped, so I cleaned it up with an 8x20 tap and guess what.
The screws went right in.
The DESIGN of these things is amazing. What is the reason for the screws
being designed not to come all the way out. And, did I compromise something
by cleaning up whatever it was that strips when you do remove the screws?
LM
> The third conductor is _NOT_ the neutral serving as ground, it is
> THE_GROUND_CONDUCTOR_ sharing service as the neutral for the 120V
> components in the dryer (motor/lights/timer/etc.).
Very well stated!
dpb
...
> The DESIGN of these things is amazing. What is the reason for the screws
> being designed not to come all the way out. And, did I compromise something
> by cleaning up whatever it was that strips when you do remove the screws?
a) So they don't get lost???? :)
b) No.
At manufacture the screws are inserted then deformed on the ends to
prevent accidentally backing them out fully. The plugs aren't designed
for other than wire loop around the screw so there's normally no need to
remove them so it's a convenience to have the resistance. Since you had
the ring terminals, what you did is fine.
I'd still suggest consideration of the conversion to a 20A circuit for a
permanent solution, however, altho I'll agree the solution is safe and
electrically compliant w/ Code intention.
--
jamesgangnc
I agree. If this is an"extra" dryer outlet in the garage I'd take
consider switching it. A 20 amp breaker is only about $10. Another
$10 would get you a metal box and proper 20amp outlet. The wire is
already there. If it doesn't have a ground you could use the neutral
as long as you mark it as ground.
FatterDumber& Happier Moe
Jesus Christ, with all this advice you will be lucky if you don't burn
the house down and put the lights out in the whole neighborhood. Just
go to Home Depot and get a receptacle that fits the plug. Turn off the
breakers and remove the old 30 amp receptacle and install the new 20 amp
one. The "hot" wires go on the outside screws they should be colored
and the ground/neutral on the middle one white if it was done correctly,
might be bare if someone took a short cut. Flip the breakers back on
and there should be 115 volts between each of the outside holes to
neutral/ground holes and 220 volts from outside hole to outside hole.
Plug the thing in and turn it on and get that basket ball aired up.
Working air compressors are just real handy to have around, I use
mine for lots of things, great for blowing out a dusty old computer,
adjusting the pressure in the car tires, gobs of uses.
Elmo
> I just want advice for the conversion I just did before I plug it all in.
Here's the summary after reading all the posts, especially djb's (Dave
Bot..o perhaps?) posts.
1. The BEST approach is, all agree, to replace the NEMA 10-30R dedicated
dryer receptacle and 30 amp breaker with a NEMA 6-20R and a 20 amp breaker.
2. However, the use of a well-made adapter will be just as safe and
"compliant" to code, for temporary use (e.g., once every few months for a
few minutes).
3. The two 120V hot wires match up one-to-one; what doesn't match (at
first) are the two inconsistencies (a) amperage, and (b) ground/neutral
4. Taking amperage first, the 30 amp circuit is protecting the house
wiring, not the load. The 15 amp load will not cause a safety hazard to the
house wiring. The load has its own overcurrent protection on the motor.
5. Taking the contentious ground/neutral situation next, djb summed it up
best by clarifying the W wire in the grandfathered NEMA 10-30R receptacle
is a ground for the 240 volts of the compressor. So it's a one-to-one match
of the NEMA 6-20P plug ground to the NEMA 10-30R receptacle ground (via the
adapter cord).
6. If we were to plug in a non-existent dryer, then (and only then), would
the NEMA 10-30R receptacle ground wire be also carrying dual duty as the
110 volt neutral (for the dryer 110V circuitry).
In summary, it appears, as long as my adapter is well made (picture of it
below), it's safe (even safer than plugging in a dryer) to plug in the cord
that I made.
A picture of the adapter cord and compressor is here:
http://img534.imageshack.us/i/006ary.jpg/
http://img153.imageshack.us/i/005tqn.jpg/
http://img714.imageshack.us/i/004wtt.jpg/
http://img525.imageshack.us/i/003zpn.jpg/
http://img809.imageshack.us/i/007pet.jpg/
http://img828.imageshack.us/i/002nd.jpg/
http://img265.imageshack.us/i/001aaz.jpg/
cl...@snyder.on.ca
<evan.ne...@earthlink.net> wrote:
>On Jul 25, 2:06 am, Elmo <dcdraftwo...@Use-Author-Supplied-
>Address.invalid> wrote:
>> I just want advice for the conversion I just did before I plug it all in.
>>
>> Details:
>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
>> plug with one blade sideways (otherwise it looks like a normal 120V
>> grounded plug).
>>
>> 2. I have no sockets in the house which fit that 220 volt plug.
>>
>> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
>> hots and a neutral).
>>
>> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>> plug with the one blade sideways.
>>
>> Before I plug in the compressor to the recepticle to the dryer cord to the
>> recepticle, would you have any concerns about safety or other?
>>
>> I assumed the neutral in the compressor plug was the center wire (looks
>> like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>> is the L-shaped center pin. Is that the correct assumption for the shared
>> neutral?
>
>
>Ummm yeah... Why would you want to plug a 20 amp 240 volt appliance
>which uses a NEMA 6-20 cord configuration into a 30 amp outlet made
>for
>a NEMA 10-30 cord configuration by means of using a cord adapter which
>you have created yourself...
>
>There is a reason why the outlets for vastly different amperage
>ratings do
>not fit into each other... SAFETY...
>
>Why not have a correct 20 amp 240 volt NEMA 6-20 outlet installed in
>your
>home so you can use your compressor safely on a circuit which is not
>capable of supplying more power than your appliance is rated for which
>could damage it or cause an accident of some kind...
>
>~~ Evan
Evan - sorry but your ignorance is showing. Virtually every item you
plug into a 15 or 20 amp 115 volt receptacle in your home is rated
MUCH below the 15 or 20 amps the receptacle is rated at, and the
breaker is designed for. It is NOT a safety issue. Your computer draws
something like 2 amps, the monitor 1/2 amp, a 100 watt light bult less
than an amp, your fancy little transistor table radio about 250
milliamps.
The "right" way to do it would be a "fused adapter" with a 30 amp plug
that fits the dryier receptacle, and a 20 amp receptacle to fit the
compressor plug, with a 20 amp fuse or breaker between the two. This
would protect the wiring to the compressor motor - which, in all
likelihood, already has a thermal shutdown protection device built
into it - making the fused adapter redundant anyways.
cl...@snyder.on.ca
>On Jul 25, 2:06 am, Elmo <dcdraftwo...@Use-Author-Supplied-
>Address.invalid> wrote:
>> I just want advice for the conversion I just did before I plug it all in.
>>
>> Details:
>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
>> plug with one blade sideways (otherwise it looks like a normal 120V
>> grounded plug).
>>
>> 2. I have no sockets in the house which fit that 220 volt plug.
>>
>> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
>> hots and a neutral).
>>
>> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>> plug with the one blade sideways.
>>
>> Before I plug in the compressor to the recepticle to the dryer cord to the
>> recepticle, would you have any concerns about safety or other?
>>
>> I assumed the neutral in the compressor plug was the center wire (looks
>> like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>> is the L-shaped center pin. Is that the correct assumption for the shared
>> neutral?
>
>Yes, the L shaped prong is the nuetral on a 3 wire dryer. The other
>two are the hots. Your compressor more likely needs 2 hots and a
>ground. While what you are doing is not exactly by the book it will
>run your compressor. The safety issue is that you will be using your
>nuetral line for a ground and using a 30 amp circuit where a 20 amp
>one is called for. What you really need to do is install a dedicated
>220 outlet in the location of your compressor. Have you looked at the
>compressor to see if it can be run on 110? Many motors have alternate
>wiring that allows them to run on 220 or 110.
If it is a 20 amp 220 plug on the compressor, it would need 40 amps
at 110, which is very non-standard. Assuming the 20 amp plug is
already over-sized a bit, he might get away with a 30 amp 110 volt
circuit - which again is definitely "non-standard" in today's
residentiial wiring scheme.
cl...@snyder.on.ca
Actually, the dryer may have an issue with today's code as it is
using the "ground" as a neutral for the 110 volt lamp, motor, and
timer circuits. Today's code (at least here in Ontario Canada)
requires a FOUR wire plug for dryers and other 220 volt devices that
use 110 volts as well.
The compressor is a straight 220 device - not requiring a neutral
(which is being "faked" on the ground on a 3 wire plug)
Jon Danniken
>
> Working air compressors are just real handy to have
> around, I use mine for lots of things, great for blowing out a dusty old
> computer,
> adjusting the pressure in the car tires, gobs of uses.
I've had a compressor for over a decade, but I've only had air tools (impact
and ratchet, also nail and brad guns) for a couple of years. Makes working
on the car _so_ much easier, I can't believe it took me so long to get them!
Jon
cl...@snyder.on.ca
>
>"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in message
>news:i2gk9k$pb1$1...@tioat.net...
>>I just want advice for the conversion I just did before I plug it all in.
>>
>> Details:
>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220
>> volt
>> plug with one blade sideways (otherwise it looks like a normal 120V
>> grounded plug).
>>
>> 2. I have no sockets in the house which fit that 220 volt plug.
>>
>> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
>> hots and a neutral).
>>
>> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>> plug with the one blade sideways.
>>
>> Before I plug in the compressor to the recepticle to the dryer cord to the
>> recepticle, would you have any concerns about safety or other?
>>
>> I assumed the neutral in the compressor plug was the center wire (looks
>> like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>> is the L-shaped center pin. Is that the correct assumption for the shared
>> neutral?
>
>Your setup will work as you describe. The Nec prohibits using a 20 amp
>receptacle on a 30 amp circuit.
>Provided that the motor has built in overcurrent protection, I would install
>a 30 amp dryer cord set directly on the compressor
>
Zip tie the 20 amp "receptacle" to the compressor cord and it is no
longer a receptacle but part of the compressor, and that portion of
the code is no longer applicable.
cl...@snyder.on.ca
<dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
>On Sun, 25 Jul 2010 03:51:43 -0400, mm wrote:
>> Also get a meter that goes up to 250 VAC and measure the voltage at
>> all three slots of the receptacle, relative to ground.
>
>I did use the Fluke DMM to measure the connections; I was just double
>checking which was the ground/neutral because I didn't wire the house in
>the first place.
>
>The ground in the two-phase 220v compressor NEMA 6-20P plug should be the
>center pin and the ground/neutral in the NEMA10-30R dryer receptacle should
>be the L-shaped center prong.
>
>The two questions I would like to ask here are:
>a) How do I know if the NEMA10-30R is on a sub panel (it's inches from the
>main panel on the other side of the wall outside the garage)?
>b) Are my tests correct that the ground on the 20-amp NEMA 6-20P plug is
>"equivalent" to the ground/neutral on the 30-amp NEMA10-30R receptacle?
You are right and safe. Use it.
Gordon Shumway
<dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
>I just want advice for the conversion I just did before I plug it all in.
>
>Details:
>1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
>plug with one blade sideways (otherwise it looks like a normal 120V
>grounded plug).
>
>2. I have no sockets in the house which fit that 220 volt plug.
>
>3. I have a three-pronged dryer socket in the garage with 220 volts (two
>hots and a neutral).
>
>4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>plug with the one blade sideways.
>
>Before I plug in the compressor to the recepticle to the dryer cord to the
>recepticle, would you have any concerns about safety or other?
>
>I assumed the neutral in the compressor plug was the center wire (looks
>like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>is the L-shaped center pin. Is that the correct assumption for the shared
>neutral?
The only thing I can say is what has already been said. If you have
to ask these questions you should not be doing this job. This is
something left for the professionals.
Consider what could happen to your family if you assume wrong...
RBM
"Gordon Shumway" <Rho...@Planet.Melmac> wrote in message
news:spso46hguvam5suso...@4ax.com...
The compressor won't work, and they'll run out of air?
cl...@snyder.on.ca
<ichase...@notgmail.com> wrote:
>On 7/25/2010 1:06 AM, Elmo wrote:
>> I just want advice for the conversion I just did before I plug it all in.
>>
>> Details:
>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
>> plug with one blade sideways (otherwise it looks like a normal 120V
>> grounded plug).
>>
>> 2. I have no sockets in the house which fit that 220 volt plug.
>>
>> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
>> hots and a neutral).
>>
>> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>> plug with the one blade sideways.
>>
>> Before I plug in the compressor to the recepticle to the dryer cord to the
>> recepticle, would you have any concerns about safety or other?
>>
>> I assumed the neutral in the compressor plug was the center wire (looks
>> like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
>> is the L-shaped center pin. Is that the correct assumption for the shared
>> neutral?
>
>I'm suspecting that out of all these replies, NONE are correct. What i
>suspect is that you have a 20a plug on a 120V compressor and you just
>don't have any 20a 120v outlets in your house. Better look a little
>closer at everything before you feed that unit 240v.
HOLD ON - I think Steve caught something I missed - you did say ONE
blare is crosswise, not 2 - right? That COULD BE a NEMA 5-20 plug. oR
IT COULD BE A 6-20.
BOTH crosswise would be a 6-15.
WHEN YOU HOLD THE PLUG WITH THE PINS FACING YOU AND THE "U" GROUND
DOWN, WHICH SIDE HAS THE "ROTATED" BLADE??
Rotated blade on the right os a 5-20 - 115 volt 20 amp. (nominal)
Rotated blade on the left is a 6-20 - 230 volt 20 amp (nominal).
If it is a Nema 6-20, go ahead you are OK (and I think you DID say it
was a 6-20R that you were using - which would not let a 5-20P fit)
cl...@snyder.on.ca
<dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
>On Sun, 25 Jul 2010 01:04:05 -0700, Smitty Two wrote:
>> Really? Two phase? How old is this gadget, anyway?
>
>You know, I bought it that damn Sears Craftsman compressor on a whim in a
>sale in the 80's. It was (on sale), about 350 or 400 bucks.
>
>Then, when I brought the huge thing home, I realized I didn't have an
>outlet for it, so I just let it sit for a year or so. Then I moved, and
>didn't have an outlet for it, so I let it sit for a few years. Finally I
>moved to a place that had the outlet, and I used it every six months or so
>to blow up the kids toys. I moved again, and guess what, no outlet.
>
>Funny thing is that I've seen Sears compressors on sale over and over and
>over and over again for, guess what, just about 350 or 400 bucks. They
>never changed prices in decades. Amazing.
>
>In hind sight, I never should have bought it as I barely used it due to the
>cord and the lack of needs.
>
>However, I still have it. And I actually want to blow up a kids toy and
>then figured I'd plug the NEMA 6-20P into an adaptor consisting of a NEMA
>6-20R and a NEMA10-30P and then connect to the NEMA10-30R fused by a 30-amp
>circuit for my 20-amp compressor.
>
>I was just asking advice, specifically:
>a) How do I know that I'm NOT on a sub panel?
>b) Did I pick the correct ground/neutral?
>
>Is there anything else I didn't think of (before I plug it in)?
Doesn't really matter if you are on a sub-panel or not as you are not
using the "neutral" - it is simply a "safety ground" - and YES, you
did pick the right neutral (actually, ground)
cl...@snyder.on.ca
>
>"Steve Barker" <ichase...@notgmail.com> wrote in message
>news:EvWdnWAEdY8fodHR...@giganews.com...
>> On 7/25/2010 1:06 AM, Elmo wrote:
>>> I just want advice for the conversion I just did before I plug it all in.
>>>
>>> Details:
>>> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220
>>> volt
>>> plug with one blade sideways (otherwise it looks like a normal 120V
>>> grounded plug).
>>>
>>> 2. I have no sockets in the house which fit that 220 volt plug.
>>>
>>> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
>>> hots and a neutral).
>>>
>>> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
>>> plug with the one blade sideways.
>>>
>>> Before I plug in the compressor to the recepticle to the dryer cord to
>>> the
>>> recepticle, would you have any concerns about safety or other?
>>>
>>> I assumed the neutral in the compressor plug was the center wire (looks
>>> like a ground pin) while I assumed the neutral on the 3-pronged dryer
>>> cord
>>> is the L-shaped center pin. Is that the correct assumption for the shared
>>> neutral?
>>
>> I'm suspecting that out of all these replies, NONE are correct. What i
>> suspect is that you have a 20a plug on a 120V compressor and you just
>> don't have any 20a 120v outlets in your house. Better look a little
>> closer at everything before you feed that unit 240v.
>>
>> --
>> Steve Barker
>> remove the "not" from my address to email
>
>Very good point. Most of these small compressors run 120 or 240 volts, and
>do require a 20 amp plug @120 volt. It is entirely probable that the OP is
>looking at a 20 amp 120 volt plug and not a 20 amp 240 volt plug, which are
>very similar looking
>
If his copressor plug fits the 6-30R he bought, I strongly suspect
your suspicion is wrong.
Gordon Shumway
>> Consider what could happen to your family if you assume wrong...
>
>The compressor won't work, and they'll run out of air?
That's one possibility I hadn't thought of. Another possibility is
the compressor will suck. That's the logical possibility. After all,
it is a Craftsman compressor...
RBM
<cl...@snyder.on.ca> wrote in message
news:84uo4693fhdp5n858...@4ax.com...
When you're dealing with amateurs, there are many ifs. With the similarities
between nema 20 amp 120 and 240 devices, it's difficult to determine what he
bought, or thought he bought, however as the string progressed, it became
clear that he does indeed have a 240 volt machine. Had you followed the
progression, you may have noticed this as well.
dpb
...
> ... If it doesn't have a ground you could use the neutral
> as long as you mark it as ground.
no, No, NO, _NO_!!!
One more time...the third wire in a 3-wire dryer circuit _IS_THE_GROUND_
wire allowed by previous NEC to double as the 120V neutral. It is not,
repeat _NOT_ connected to the neutral bus.
--
RBM
"Gordon Shumway" <Rho...@Planet.Melmac> wrote in message
Yea, but it's on old Craftsman, from when the sucked less
RBM
"dpb" <no...@non.net> wrote in message
news:i2hv2q$33d$1...@news.eternal-september.org...
>
It has to original at the service panel, where the neutral/ground conductor
of the dryer cable connects to the neutral/ground buss of the panel. It
cannot originate in a sub panel where you have separate neutral and ground
busses
> --
RBM
"RBM" <rb...@live.com> wrote in message
news:4c4c82bd$0$5010$607e...@cv.net...
My mistake, it has to originate in the service panel if type SE cable is
used. If a cable with an insulated neutral is used, it can originate in a
sub panel, in which case the neutral/ground conductor would go to the
neutral buss
>
>
cl...@snyder.on.ca
"the sky is falling, The SKY is FALLING" - Chicken Little.
Steve B
You'll shoot yer eye out, kid?
Three wires is pretty hard to screw up. The only thing is that the
dryer/range plug will have too big a breaker, and if the compressor
overheats, it won't pop off in time to save it.
Steve
visit my blog at http://cabgbypasssurgery.com
Stormin Mormon
socket.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in
message news:i2gk9k$pb1$1...@tioat.net...
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"RBM" <rb...@live.com> wrote in message
news:4c4c46d0$0$4994$607e...@cv.net...
If that's the case, why don't you just replace the breaker and
receptacle
with a 20 amp
Stormin Mormon
the same place for year, the larger compressor is good.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in
message news:i2hh5u$20r$1...@tioat.net...
I've had the compressor for 30 years and barely used it because of
this
damn plug. If I can give any advice to a young 30 year old kid buying
his
first compressor, it would be to get a 110V smaller one!
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Jon Danniken" <jonSPAMMEN...@yahSPAMhoo.com> wrote in message
news:i2hs0d$d8l$1...@speranza.aioe.org...
Dan Lanciani
| I wondered about that. Does the "code" cover temperary adapters?
That's an interesting question. I've noticed that marine stores sell
a lot of twist-lock adapters and the "odd" configurations (like 30A male
with 15A female) are not UL listed (or say something like "made with
UL-listed parts) while the matched amperage ones have the UL hologram.
So maybe the answer is that UL covers this, but nothing stops people
from selling, buying, and using adapters that UL won't list.
Dan Lanciani
ddl@danlan.*com
k...@att.bizzzzzzzzzzzz
Why would the lack of a UL rating stop people from selling something? UL
isn't the government.
Elmo
> I wouldn't want to plug a two phase compressor into a single phase
> socket.
I read everything stated in all the helpful posts, and I only have two
things that I'm not sure of at this point, neither of which were questions
initially.
1. The 30-year old Craftsman compressor (model 919.176940, nameplate says
240 volts, 15 amps) certainly uses two hot wires ... but since it's using
the third (green on the compressor, white on the adapter) wire as a ground,
I guess it's really not TWO phase but really one phase.
Is it in actuality just a one phase two hundred volt motor?
2. Since the garage dryer receptacle is just on the other side of the main
panel, I assume it's connected to the main panel; but I need to check. What
I'll do, before plugging in the compressor, is stick a DMM into it and then
hit the breakers.
Is there any other way to tell that you're NOT on a sub panel?
RBM
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in message
> On Sun, 25 Jul 2010 15:45:35 -0400, Stormin Mormon wrote:
>> I wouldn't want to plug a two phase compressor into a single phase
>> socket.
>
> I read everything stated in all the helpful posts, and I only have two
> things that I'm not sure of at this point, neither of which were questions
> initially.
>
> 1. The 30-year old Craftsman compressor (model 919.176940, nameplate says
> 240 volts, 15 amps) certainly uses two hot wires ... but since it's using
> the third (green on the compressor, white on the adapter) wire as a
> ground,
> I guess it's really not TWO phase but really one phase.
>
> Is it in actuality just a one phase two hundred volt motor?
It is a single phase 240 volt motor
>
> 2. Since the garage dryer receptacle is just on the other side of the main
> panel, I assume it's connected to the main panel; but I need to check.
> What
> I'll do, before plugging in the compressor, is stick a DMM into it and
> then
> hit the breakers.
>
> Is there any other way to tell that you're NOT on a sub panel?
For your purposes, it doesn't matter if it's connected to a sub panel
Bob
> Why would the lack of a UL rating stop people from selling something? UL
> isn't the government.
UL isn't a government agency, but some jurisdictions may require
electrical products to be listed by UL or similar organization in order
to be sold there.
The UL listing only means that the product is deemed safe *for its
intended purpose.* A listed 18-gauge extension code is safe when run
along a wall for a table lamp, while it can be a fire hazard if run
under a carpet to power an air conditioner and microwave oven.
--
Evan
> On Sun, 25 Jul 2010 00:36:55 -0700 (PDT), Evan
>
>
>
> <evan.news.re...@earthlink.net> wrote:
> >On Jul 25, 2:06 am, Elmo <dcdraftwo...@Use-Author-Supplied-
> >Address.invalid> wrote:
> >> I just want advice for the conversion I just did before I plug it all in.
>
> >> Details:
> >> 1. I have a two-phase 220V Sears Craftsman compressor which uses a 220 volt
> >> plug with one blade sideways (otherwise it looks like a normal 120V
> >> grounded plug).
>
> >> 2. I have no sockets in the house which fit that 220 volt plug.
>
> >> 3. I have a three-pronged dryer socket in the garage with 220 volts (two
> >> hots and a neutral).
>
> >> 4. I just attached a new 3-pronged male dryer cord to a female 220 volt
> >> plug with the one blade sideways.
>
> >> Before I plug in the compressor to the recepticle to the dryer cord to the
> >> recepticle, would you have any concerns about safety or other?
>
> >> I assumed the neutral in the compressor plug was the center wire (looks
> >> like a ground pin) while I assumed the neutral on the 3-pronged dryer cord
> >> is the L-shaped center pin. Is that the correct assumption for the shared
> >> neutral?
>
> >which uses a NEMA 6-20 cord configuration into a 30 amp outlet made
> >for
> >a NEMA 10-30 cord configuration by means of using a cord adapter which
> >you have created yourself...
>
> >There is a reason why the outlets for vastly different amperage
> >ratings do
> >not fit into each other... SAFETY...
>
> >Why not have a correct 20 amp 240 volt NEMA 6-20 outlet installed in
> >your
> >home so you can use your compressor safely on a circuit which is not
> >capable of supplying more power than your appliance is rated for which
> >could damage it or cause an accident of some kind...
>
> >~~ Evan
>
> Evan - sorry but your ignorance is showing. Virtually every item you
> plug into a 15 or 20 amp 115 volt receptacle in your home is rated
> MUCH below the 15 or 20 amps the receptacle is rated at, and the
> breaker is designed for. It is NOT a safety issue. Your computer draws
> something like 2 amps, the monitor 1/2 amp, a 100 watt light bult less
> than an amp, your fancy little transistor table radio about 250
> milliamps.
>
> The "right" way to do it would be a "fused adapter" with a 30 amp plug
> that fits the dryier receptacle, and a 20 amp receptacle to fit the
> compressor plug, with a 20 amp fuse or breaker between the two. This
> would protect the wiring to the compressor motor - which, in all
> likelihood, already has a thermal shutdown protection device built
> into it - making the fused adapter redundant anyways.
Umm... No... It is not ignorance... The CONVENIENCE outlets
in your home are designed for that purpose...
When you are talking about dedicated circuits for non-convenience
loads your logic about that is faulty...
If it isn't designed to fit into that outlet it shouldn't be used with
it...
~~ Evan
Evan
Address.invalid> wrote:
> On Sun, 25 Jul 2010 06:06:44 +0000 (UTC), Elmo wrote:
> > I just want advice for the conversion I just did before I plug it all in.
>
> Bot..o perhaps?) posts.
>
> 1. The BEST approach is, all agree, to replace the NEMA 10-30R dedicated
> dryer receptacle and 30 amp breaker with a NEMA 6-20R and a 20 amp breaker.
>
> 2. However, the use of a well-made adapter will be just as safe and
> "compliant" to code, for temporary use (e.g., once every few months for a
> few minutes).
>
> 3. The two 120V hot wires match up one-to-one; what doesn't match (at
> first) are the two inconsistencies (a) amperage, and (b) ground/neutral
>
> 4. Taking amperage first, the 30 amp circuit is protecting the house
> wiring, not the load. The 15 amp load will not cause a safety hazard to the
> house wiring. The load has its own overcurrent protection on the motor.
>
> 5. Taking the contentious ground/neutral situation next, djb summed it up
> best by clarifying the W wire in the grandfathered NEMA 10-30R receptacle
> is a ground for the 240 volts of the compressor. So it's a one-to-one match
> of the NEMA 6-20P plug ground to the NEMA 10-30R receptacle ground (via the
> adapter cord).
>
> 6. If we were to plug in a non-existent dryer, then (and only then), would
> the NEMA 10-30R receptacle ground wire be also carrying dual duty as the
> 110 volt neutral (for the dryer 110V circuitry).
>
> In summary, it appears, as long as my adapter is well made (picture of it
> below), it's safe (even safer than plugging in a dryer) to plug in the cord
> that I made.
>
> A picture of the adapter cord and compressor is here:http://img534.imageshack.us/i/006ary.jpg/http://img153.imageshack.us/i/005tqn.jpg/http://img714.imageshack.us/i/004wtt.jpg/http://img525.imageshack.us/i/003zpn.jpg/http://img809.imageshack.us/i/007pet.jpg/http://img828.imageshack.us/i/002nd.jpg/http://img265.imageshack.us/i/001aaz.jpg/
That is seriously the STUPIDEST thing I have ever seen
made out of electrical components...
You don't know how to put a cord end on a cord ?
Also, you could CUT the pre-made ring terminations off
of the dryer cord you purchased and used wire nuts to
make pigtails that would have fit the screw terminals
on the side of that outlet you are using...
Just because you have made something that provides
power doesn't mean you have done so properly or
safely...
~~ Evan
k...@att.bizzzzzzzzzzzz
>On 7/25/2010 15:00, k...@att.bizzzzzzzzzzzz wrote:
>
>> Why would the lack of a UL rating stop people from selling something? UL
>> isn't the government.
>
>UL isn't a government agency, but some jurisdictions may require
>electrical products to be listed by UL or similar organization in order
>to be sold there.
Citation please.
>The UL listing only means that the product is deemed safe *for its
>intended purpose.* A listed 18-gauge extension code is safe when run
>along a wall for a table lamp, while it can be a fire hazard if run
>under a carpet to power an air conditioner and microwave oven.
Sure, but it is nothing more.
Gordon Shumway
>>Consider what could happen to your family if you assume wrong...
>"the sky is falling, The SKY is FALLING" - Chicken Little.
Maybe. I don't know about you but I hope I never live next to someone
that thinks they know how to work with electricity only to find out
they know how to burn their house down.
Elmo
> For your purposes, it doesn't matter if it's connected to a sub panel
Well, after reading everything, I put it all together and plugged it in and
tested it and it worked just fine.
I finally have a convenient way to plug in the old compressor.
Thanks for all your help!
Elmo
> Just because you have made something that provides
> power doesn't mean you have done so properly or
> safely...
Hi Evan,
Thanks for the advice after looking at the pictures of the adapter.
You're the only one to comment on the pictures of the adapter.
The ring terminals caused no problem; and certainly the way I did it is as
safe as any other method ... but you mention the strain relief???
Do you have a picture of how it should be done if the way I did it is
either improper or unsafe?
Stormin Mormon
As to being on a sub panel, only way I know would be to trace the
wires, and look for one. Does your house even have a sub panel?
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Elmo" <dcdraf...@Use-Author-Supplied-Address.invalid> wrote in
message news:i2idol$9g3$1...@tioat.net...
cl...@snyder.on.ca
First question - do you know you even HAVE a sub-panel?????? If you
don't have one it's pretty obvious it's not connected to one.
mm
<dcdraf...@Use-Author-Supplied-Address.invalid> wrote:
>On Sun, 25 Jul 2010 03:51:43 -0400, mm wrote:
>> Also get a meter that goes up to 250 VAC and measure the voltage at
>> all three slots of the receptacle, relative to ground.
>
>I did use the Fluke DMM to measure the connections; I was just double
>checking which was the ground/neutral because I didn't wire the house in
>the first place.
Okay. Good. I jumped to the conclusion that you hadn't.
>
>The ground in the two-phase 220v compressor NEMA 6-20P plug should be the
>center pin and the ground/neutral in the NEMA10-30R dryer receptacle should
>be the L-shaped center prong.
>
>The two questions I would like to ask here are:
>a) How do I know if the NEMA10-30R is on a sub panel (it's inches from the
>main panel on the other side of the wall outside the garage)?
>b) Are my tests correct that the ground on the 20-amp NEMA 6-20P plug is
>"equivalent" to the ground/neutral on the 30-amp NEMA10-30R receptacle?
You keep using "ground/neutral" wrt the receptacle. I think you mean
ground. The neutral is one of the two main slots in a *110* volt
receptacle. It carries full current when something is using the
recept. But it's voltage wrt ground is zero. But that's not the
same as being a ground. It's a neutral.
OTOH, in *220*, two of the wires are hot though at different
potentials wrt ground. Only the ground is without voltage, but if you
call it neutral, I'm pretty sure you will confuse some people, or
their reply to you will confuse you, and that could lead to a mistake.
Elmo
> You keep using "ground/neutral" wrt the receptacle.
> I think you mean ground.
You are correct sir!
I only belatedly, half way through this thread, realized that the green
ground wire on the 240 volt compressor was connecting to the white ground
wire of the 240 volt dryer receptacle.
If a DRYER were hooked up, then that white third wire in the dryer
receptacle would be doing double duty as a ground (for the 240 volt
circuitry of the dryer) and neutral (for the 120 volt circuitry of the
dryer).
But, I learned in this thread, that the dryer receptacle in the wall has
its white ground/neutral wire hooked to ground in the panel. So, even
though that white wire does double duty (when a dryer is hooked up), for
the compressor, I'm hooking ground to ground so there is no additional
danger because current is not being carried in this ground wire.
Thanks for all your help. The compressor worked flawlessly when I hooked it
up. I only got one comment on the pictures of the adapter so I'd appreciate
if anyone could tell me how to improve it.
Elmo
> First question - do you know you even HAVE a sub-panel?????? If you
> don't have one it's pretty obvious it's not connected to one.
I tested it on the main panel and the power to the 240 volt receptacle
switched off when I hit one of the breakers on the main panel.
Yes, I have multiple sub panels. The house has had multiple additions by
previous owners. In fact, the actual dryer is in one of those additions,
so, I suspect (I didn't check) that it's on a sub panel.
Elmo
> As to being on a sub panel, only way I know would be to trace the
> wires, and look for one. Does your house even have a sub panel?
There are multiple sub panels as the house has had wings added over time by
previous owners.
The one problem with my "test" of hitting one of the breakers is that
breaker could, I guess, have actually been going to a sub panel, in which
case all circuits on that sub panel would have gone out.
I think someone said it doesn't really matter if it's on a sub panel anyway
because the white wire is physically wired as a ground in the main panel
and in the sub panels, not as a neutral.
bud--
>
> I think someone said it doesn't really matter if it's on a sub panel anyway
> because the white wire is physically wired as a ground in the main panel
> and in the sub panels, not as a neutral.
The branch circuit has to originate at the service (250.140). I believe
that has always been the requirement. If it goes to a subpanel, it
violated the NEC when installed.
At a subpanel, if you are connecting a drier and connect the white wire
to "ground" you are putting current on the ground wires. Among the
problems is if the ground back to the source fails this could make all
the downstream grounds hot. If you connect to the neutral bar, if there
is a problem with the supply neutral the drier frame could be way above
ground potential.
IMHO you should at least determine what the major breakers feed and
label them.
--
bud--