"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> I'm going to purchase a air compressor which as a 7hp rating so I guess
it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
>
> Regards
>
>
It may be less than you think! I have a 7 HP Porter Cable compressor, it is
in reality about 3 HP.
The specs you need to know will be on the motor. You need to size the
breaker so the motor draw as lower than 80% of the breakers rating. In my
case the motor was rated at 15 amps@ 240 volts, I am running it on a double
pole 20 amp breaker.
Greg
"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> I got 10% off the same model from CH's hot buy($580) for opening up a new
> account at lowes so the price was 570. It's rated at 4hp and 17.3 amps and
> so far runs great on a 15amp breaker, but I will upgrade to a 20amp later
> this weekend. See new post for air line setup.
>
>
Make sure the wiring is sized for the twenty amp breaker. It needs to be at
least 12 ga. or larger for a long run.
If it is on a 15 amp breaker now, I would suspect 14 ga. wire, much too
light for a twenty amp breaker.
Greg
In article <1V%[email protected]>, Searcher
<[email protected]> wrote:
> I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was only
> going to run it off our secondary clothes dryer feed (we no longer use it).
> It would have been an easy hookup, but my electrician said that the 40A
> could possibly be too much for it. For the price of a new breaker I have a
> better piece of mind that I am not going to overload the motor with 40 A
> when it only requires 15A. So I gave it a 20A breaker/
If that's your electrician's understanding of electricity, you need a
new electrician.
Kevin
I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was only
going to run it off our secondary clothes dryer feed (we no longer use it).
It would have been an easy hookup, but my electrician said that the 40A
could possibly be too much for it. For the price of a new breaker I have a
better piece of mind that I am not going to overload the motor with 40 A
when it only requires 15A. So I gave it a 20A breaker/
Rich
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
> "Woodchuck" writes:
>
> > I'm going to purchase a air compressor which as a 7hp rating so I guess
> it's
> > really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> > Question, how many amp breaker is needed and typically what current does
a
> > compressor like this draw.
>
> Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed the
> compressor.
>
> It's what I've used for a 5HP, 2 stage unit for the last 10 years.
>
> HTH
>
> Lew
>
>
>
Most motors in the consumer market have internal overload protection. The
allowable overcurrent device is generally allowed to be up to 250% of the FLA
on the nameplate, rounded UP to the next standard breaker size.
Legally you could put a 15a FLA motor on 14 ga wire (you CAN use 310-16 not
240.4(D)) with a 40a breaker (430.52). At that point voltage drop would be a
bigger consideration than anything else.
In article <[email protected]>, Woodchuck wrote:
> I'm going to purchase a air compressor which as a 7hp rating so I guess it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
My 5HP motor is 21 amps at 240 volts. That said, the motor is a replacement
for a three phase unit and I didn't know about "compressor horsepower". My
motor is 5HP continuous duty, not intermittent. It's on a 30 amp breaker.
Just got back from sears and HD. Sears had a 5hp which the motor was rated
at 22.5FLA. What does FLA mean. HD had a advertised 7hp rated at 17.3amps.
When I looked at the HD 2 weeks ago it was $100 less than tonight? So
Saturday I'm going to Lowes an see what they have, but online I'm leaning to
this one.#20849 for $637 in my area and if I open a new charge I think I can
get 10%. Will check the specs and get back to you all.
"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> I'm going to purchase a air compressor which as a 7hp rating so I guess
it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
>
> Regards
>
>
In article <[email protected]>,
Greg <[email protected]> wrote:
>FLA=Full Load Amps
>
>17FLA is nominally 3hp motor at 230v
>28FLA is 5 HP
>
>per 430.148 in the NEC
Looks like some _dreadful_ efficiency numbers, or a humongous phase-angle.
3hp == 2237 watts.
17A @ 230v is 3910 VA (or watts at 0 phase-angle.)
17A @ 240V is 4080 VA (or watts at 0 phase-angle.)
2237::3910 equates to a 57.212% efficiency
2237::4080 equates to a 54.828% efficiency.
Postulating 85% mechanical efficiency for the motor, that gets an
input power of 2632 watts.
Takes a _substantial_ phase-angle to make 2600 watts equivalent to 3900 VA.
Robert Bonomi wrote:
> In article <[email protected]>,
> Greg <[email protected]> wrote:
>>FLA=Full Load Amps
>>
>>17FLA is nominally 3hp motor at 230v
>>28FLA is 5 HP
>>
>>per 430.148 in the NEC
>
> Looks like some _dreadful_ efficiency numbers, or a humongous phase-angle.
>
> 3hp == 2237 watts.
>
> 17A @ 230v is 3910 VA (or watts at 0 phase-angle.)
> 17A @ 240V is 4080 VA (or watts at 0 phase-angle.)
>
> 2237::3910 equates to a 57.212% efficiency
> 2237::4080 equates to a 54.828% efficiency.
>
> Postulating 85% mechanical efficiency for the motor, that gets an
> input power of 2632 watts.
>
> Takes a _substantial_ phase-angle to make 2600 watts equivalent to 3900
> VA.
You're missing a point. He said that that as "per 430.148 in the NEC".
That is an electrical code table used for sizing circuits, not the actual
rating or current draw of any particular installed motor.
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
Isn't the phase angle supposed to change with load?
Near 90 degrees at no load (real power minimum)
Near 0 degrees at full load Real power close to apparent power?
rhg
Robert Bonomi wrote:
> In article <[email protected]>,
> Greg <[email protected]> wrote:
>
>>FLA=Full Load Amps
>>
>>17FLA is nominally 3hp motor at 230v
>>28FLA is 5 HP
>>
>>per 430.148 in the NEC
>
>
> Looks like some _dreadful_ efficiency numbers, or a humongous phase-angle.
>
> 3hp == 2237 watts.
>
> 17A @ 230v is 3910 VA (or watts at 0 phase-angle.)
> 17A @ 240V is 4080 VA (or watts at 0 phase-angle.)
>
> 2237::3910 equates to a 57.212% efficiency
> 2237::4080 equates to a 54.828% efficiency.
>
> Postulating 85% mechanical efficiency for the motor, that gets an
> input power of 2632 watts.
>
> Takes a _substantial_ phase-angle to make 2600 watts equivalent to 3900 VA.
>
>
I got 10% off the same model from CH's hot buy($580) for opening up a new
account at lowes so the price was 570. It's rated at 4hp and 17.3 amps and
so far runs great on a 15amp breaker, but I will upgrade to a 20amp later
this weekend. See new post for air line setup.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
>
> "Woodchuck" <[email protected]> wrote in message
> news:[email protected]...
> > Just got back from sears and HD. Sears had a 5hp which the motor was
rated
> > at 22.5FLA. What does FLA mean. HD had a advertised 7hp rated at
17.3amps.
> > When I looked at the HD 2 weeks ago it was $100 less than tonight? So
> > Saturday I'm going to Lowes an see what they have, but online I'm
leaning
> to
> > this one.#20849 for $637 in my area and if I open a new charge I think I
> can
> > get 10%. Will check the specs and get back to you all.
> >
>
> Well, if you're going to be doing some shopping around then take the time
to
> go out to Campbell Hausfeld's site and look under Hot Buys. They have
some
> great deals on reconditioned compressors. Much less than retail and fully
> warranted. I don't know who builds Sear's compressors for them, but both
> Home Depot and Lowes use CH compressors. CH does not build a spec
> compressor, so what you get from HD is the same compressor that you would
> get from Lowes, or directly from CH with the possible exception that the
> private label stuff might have some extras thrown in.
> --
>
> -Mike-
> [email protected]
>
>
I used 8gauge w/g to feed my shop which has a 60 foot run and it's protected
by a 40amp breaker.
"Greg O" <[email protected]> wrote in message
news:[email protected]...
>
> "Woodchuck" <[email protected]> wrote in message
> news:[email protected]...
> > I got 10% off the same model from CH's hot buy($580) for opening up a
new
> > account at lowes so the price was 570. It's rated at 4hp and 17.3 amps
and
> > so far runs great on a 15amp breaker, but I will upgrade to a 20amp
later
> > this weekend. See new post for air line setup.
> >
> >
> Make sure the wiring is sized for the twenty amp breaker. It needs to be
at
> least 12 ga. or larger for a long run.
> If it is on a 15 amp breaker now, I would suspect 14 ga. wire, much too
> light for a twenty amp breaker.
> Greg
>
>
"CW" <no adddress@spam free.com> wrote in message
news:[email protected]...
> If your electrician said that, fire him. Amperage draw is determined by
the
> motor, not the breaker.
Not necessarily so. His electrician may have meant that he should protect
both his wiring and his motor with the proper breaker. Yes, the breaker
primarily protects the wire, but it also protects the device at the end of
the wire. A failure in the motor that won't trip the breaker until it draws
40A will be more catastrophic than one that will trip the breaker at 20A.
His electrician is correct in stating that he should size the breaker to the
load that will go on it.
--
-Mike-
[email protected]
>
> "Searcher" <[email protected]> wrote in message
> news:1V%[email protected]...
> > I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was
> only
> > going to run it off our secondary clothes dryer feed (we no longer use
> it).
> > It would have been an easy hookup, but my electrician said that the 40A
> > could possibly be too much for it. For the price of a new breaker I have
a
> > better piece of mind that I am not going to overload the motor with 40 A
> > when it only requires 15A. So I gave it a 20A breaker/
> >
> > Rich
> >
> > "Lew Hodgett" <[email protected]> wrote in message
> > news:[email protected]...
> > > "Woodchuck" writes:
> > >
> > > > I'm going to purchase a air compressor which as a 7hp rating so I
> guess
> > > it's
> > > > really a 5hp compressor. My shop has a 40amp 240v feed to my
subpanel.
> > > > Question, how many amp breaker is needed and typically what current
> does
> > a
> > > > compressor like this draw.
> > >
> > > Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed
the
> > > compressor.
> > >
> > > It's what I've used for a 5HP, 2 stage unit for the last 10 years.
> > >
> > > HTH
> > >
> > > Lew
> > >
> > >
> > >
> >
> >
>
>
If your electrician said that, fire him. Amperage draw is determined by the
motor, not the breaker.
"Searcher" <[email protected]> wrote in message
news:1V%[email protected]...
> I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was
only
> going to run it off our secondary clothes dryer feed (we no longer use
it).
> It would have been an easy hookup, but my electrician said that the 40A
> could possibly be too much for it. For the price of a new breaker I have a
> better piece of mind that I am not going to overload the motor with 40 A
> when it only requires 15A. So I gave it a 20A breaker/
>
> Rich
>
> "Lew Hodgett" <[email protected]> wrote in message
> news:[email protected]...
> > "Woodchuck" writes:
> >
> > > I'm going to purchase a air compressor which as a 7hp rating so I
guess
> > it's
> > > really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> > > Question, how many amp breaker is needed and typically what current
does
> a
> > > compressor like this draw.
> >
> > Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed the
> > compressor.
> >
> > It's what I've used for a 5HP, 2 stage unit for the last 10 years.
> >
> > HTH
> >
> > Lew
> >
> >
> >
>
>
"Woodchuck" writes:
> I'm going to purchase a air compressor which as a 7hp rating so I guess
it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed the
compressor.
It's what I've used for a 5HP, 2 stage unit for the last 10 years.
HTH
Lew
The breaker is there to protect the wiring, and that's all. If you believe
as you say, anytime you go to use an appliance, turn them all on as that
circuit will be underloaded if you don't. Never use a single corded drill in
your shop. Best turn on the dust collector too in order to load the circuit.
How's your power bill? Things must work in strange ways around your house.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
>
> "CW" <no adddress@spam free.com> wrote in message
> news:[email protected]...
> > If your electrician said that, fire him. Amperage draw is determined by
> the
> > motor, not the breaker.
>
> Not necessarily so. His electrician may have meant that he should protect
> both his wiring and his motor with the proper breaker. Yes, the breaker
> primarily protects the wire, but it also protects the device at the end of
> the wire. A failure in the motor that won't trip the breaker until it
draws
> 40A will be more catastrophic than one that will trip the breaker at 20A.
> His electrician is correct in stating that he should size the breaker to
the
> load that will go on it.
>
> --
>
> -Mike-
> [email protected]
>
> >
> > "Searcher" <[email protected]> wrote in message
> > news:1V%[email protected]...
> > > I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I
was
> > only
> > > going to run it off our secondary clothes dryer feed (we no longer use
> > it).
> > > It would have been an easy hookup, but my electrician said that the
40A
> > > could possibly be too much for it. For the price of a new breaker I
have
> a
> > > better piece of mind that I am not going to overload the motor with 40
A
> > > when it only requires 15A. So I gave it a 20A breaker/
> > >
> > > Rich
> > >
> > > "Lew Hodgett" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > "Woodchuck" writes:
> > > >
> > > > > I'm going to purchase a air compressor which as a 7hp rating so I
> > guess
> > > > it's
> > > > > really a 5hp compressor. My shop has a 40amp 240v feed to my
> subpanel.
> > > > > Question, how many amp breaker is needed and typically what
current
> > does
> > > a
> > > > > compressor like this draw.
> > > >
> > > > Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed
> the
> > > > compressor.
> > > >
> > > > It's what I've used for a 5HP, 2 stage unit for the last 10 years.
> > > >
> > > > HTH
> > > >
> > > > Lew
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
Maybe what the electrician meant was that a 40 amp breaker wouldn't
offer much protection. It would happily deliver enough amps for the
motor to fry without tripping.
rhg
CW wrote:
> If your electrician said that, fire him. Amperage draw is determined by the
> motor, not the breaker.
>
> "Searcher" <[email protected]> wrote in message
> news:1V%[email protected]...
>
>>I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was
>
> only
>
>>going to run it off our secondary clothes dryer feed (we no longer use
>
> it).
>
>>It would have been an easy hookup, but my electrician said that the 40A
>>could possibly be too much for it. For the price of a new breaker I have a
>>better piece of mind that I am not going to overload the motor with 40 A
>>when it only requires 15A. So I gave it a 20A breaker/
>>
>>Rich
>>
>>"Lew Hodgett" <[email protected]> wrote in message
>>news:[email protected]...
>>
>>>"Woodchuck" writes:
>>>
>>>
>>>>I'm going to purchase a air compressor which as a 7hp rating so I
>
> guess
>
>>>it's
>>>
>>>>really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
>>>>Question, how many amp breaker is needed and typically what current
>
> does
>
>>a
>>
>>>>compressor like this draw.
>>>
>>>Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed the
>>>compressor.
>>>
>>>It's what I've used for a 5HP, 2 stage unit for the last 10 years.
>>>
>>>HTH
>>>
>>>Lew
>>>
>>>
>>>
>>
>>
>
>
FLA = Full Load Amps
LRA = Locked Rotor Amps
1 HP = 746 watts so FLA x running voltage / 746 gives a pretty good idea
of the real HP. Take advertised HP with a grain of salt. Especially
from Sears.
Woodchuck wrote:
> Just got back from sears and HD. Sears had a 5hp which the motor was rated
> at 22.5FLA. What does FLA mean. HD had a advertised 7hp rated at 17.3amps.
> When I looked at the HD 2 weeks ago it was $100 less than tonight? So
> Saturday I'm going to Lowes an see what they have, but online I'm leaning to
> this one.#20849 for $637 in my area and if I open a new charge I think I can
> get 10%. Will check the specs and get back to you all.
>
> "Woodchuck" <[email protected]> wrote in message
> news:[email protected]...
>
>>I'm going to purchase a air compressor which as a 7hp rating so I guess
>
> it's
>
>>really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
>>Question, how many amp breaker is needed and typically what current does a
>>compressor like this draw.
>>
>>Regards
>>
>>
>
>
>
"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> Just got back from sears and HD. Sears had a 5hp which the motor was rated
> at 22.5FLA. What does FLA mean. HD had a advertised 7hp rated at 17.3amps.
> When I looked at the HD 2 weeks ago it was $100 less than tonight? So
> Saturday I'm going to Lowes an see what they have, but online I'm leaning
to
> this one.#20849 for $637 in my area and if I open a new charge I think I
can
> get 10%. Will check the specs and get back to you all.
>
Well, if you're going to be doing some shopping around then take the time to
go out to Campbell Hausfeld's site and look under Hot Buys. They have some
great deals on reconditioned compressors. Much less than retail and fully
warranted. I don't know who builds Sear's compressors for them, but both
Home Depot and Lowes use CH compressors. CH does not build a spec
compressor, so what you get from HD is the same compressor that you would
get from Lowes, or directly from CH with the possible exception that the
private label stuff might have some extras thrown in.
--
-Mike-
[email protected]
"CW" <no adddress@spam free.com> wrote in message
news:[email protected]...
> The breaker is there to protect the wiring, and that's all. If you believe
> as you say, anytime you go to use an appliance, turn them all on as that
> circuit will be underloaded if you don't. Never use a single corded drill
in
> your shop. Best turn on the dust collector too in order to load the
circuit.
> How's your power bill? Things must work in strange ways around your
house.
I know you're trying to be wise, but kindly restate this so that it makes a
bit of sense.
-Mike-
>
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "CW" <no adddress@spam free.com> wrote in message
> > news:[email protected]...
> > > If your electrician said that, fire him. Amperage draw is determined
by
> > the
> > > motor, not the breaker.
> >
> > Not necessarily so. His electrician may have meant that he should
protect
> > both his wiring and his motor with the proper breaker. Yes, the breaker
> > primarily protects the wire, but it also protects the device at the end
of
> > the wire. A failure in the motor that won't trip the breaker until it
> draws
> > 40A will be more catastrophic than one that will trip the breaker at
20A.
> > His electrician is correct in stating that he should size the breaker to
> the
> > load that will go on it.
> >
> > --
> >
> > -Mike-
> > [email protected]
> >
> > >
> > > "Searcher" <[email protected]> wrote in message
> > > news:1V%[email protected]...
> > > > I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I
> was
> > > only
> > > > going to run it off our secondary clothes dryer feed (we no longer
use
> > > it).
> > > > It would have been an easy hookup, but my electrician said that the
> 40A
> > > > could possibly be too much for it. For the price of a new breaker I
> have
> > a
> > > > better piece of mind that I am not going to overload the motor with
40
> A
> > > > when it only requires 15A. So I gave it a 20A breaker/
> > > >
> > > > Rich
> > > >
> > > > "Lew Hodgett" <[email protected]> wrote in message
> > > > news:[email protected]...
> > > > > "Woodchuck" writes:
> > > > >
> > > > > > I'm going to purchase a air compressor which as a 7hp rating so
I
> > > guess
> > > > > it's
> > > > > > really a 5hp compressor. My shop has a 40amp 240v feed to my
> > subpanel.
> > > > > > Question, how many amp breaker is needed and typically what
> current
> > > does
> > > > a
> > > > > > compressor like this draw.
> > > > >
> > > > > Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to
feed
> > the
> > > > > compressor.
> > > > >
> > > > > It's what I've used for a 5HP, 2 stage unit for the last 10 years.
> > > > >
> > > > > HTH
> > > > >
> > > > > Lew
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
>I know you're trying to be wise, but kindly restate this so that it makes a
>bit of sense.
What he is talking about is the different facets of protection in a motor
circuit. The branch circuit breaker is only there to protect from a short
circuit. Overload protection is another part of the system and that is what
protects the motor. It is also what keeps the wire from overheating.
That is why you can have things like #14 wire on a 40a breaker and still be
legal.
See the diagram at the beginning of NEC 430 to get a better understanding.
and... electric clocks aside, for larger items, like your central air,
the circuit and the load are usually matched closely enough to keep the
load itself from burning up if there should be a problem.
rhg
CW wrote:
> You do seem to have a bit of a comprehension problem. Breakers are sized to
> protect the wiring. How many 350ma breakers do you have for electric clocks?
> You must have a whole bank of them for individual light. Do you have a
> separate building to house all these?
> "Mike Marlow" <[email protected]> wrote in message
> news:Re%Vc.56$Y%[email protected]...
>
>
Thanks Greg. Saved me the trouble.
"Greg" <[email protected]> wrote in message
news:[email protected]...
> >I know you're trying to be wise, but kindly restate this so that it makes
a
> >bit of sense.
>
> What he is talking about is the different facets of protection in a motor
> circuit. The branch circuit breaker is only there to protect from a short
> circuit. Overload protection is another part of the system and that is
what
> protects the motor. It is also what keeps the wire from overheating.
> That is why you can have things like #14 wire on a 40a breaker and still
be
> legal.
> See the diagram at the beginning of NEC 430 to get a better understanding.
You do seem to have a bit of a comprehension problem. Breakers are sized to
protect the wiring. How many 350ma breakers do you have for electric clocks?
You must have a whole bank of them for individual light. Do you have a
separate building to house all these?
"Mike Marlow" <[email protected]> wrote in message
news:Re%Vc.56$Y%[email protected]...
"CW" <no adddress@spam free.com> wrote in message
news:[email protected]...
> Thanks Greg. Saved me the trouble.
Not actually. Greg responded with something intelligble while your response
both ignored what I had originally posted and jumped way too fast at the
chance to post a wise ass comment. Neither of those characteristics served
to credit you.
So let me ask you a question - would you connect your 220V tablesaw directly
to the main breaker in your panel? Besides the code requirement for a
branch circuit, and wire size, why not? Isn't it because circuits are sized
to the application?
--
-Mike-
[email protected]
>
> "Greg" <[email protected]> wrote in message
> news:[email protected]...
> > >I know you're trying to be wise, but kindly restate this so that it
makes
> a
> > >bit of sense.
> >
> > What he is talking about is the different facets of protection in a
motor
> > circuit. The branch circuit breaker is only there to protect from a
short
> > circuit. Overload protection is another part of the system and that is
> what
> > protects the motor. It is also what keeps the wire from overheating.
> > That is why you can have things like #14 wire on a 40a breaker and still
> be
> > legal.
> > See the diagram at the beginning of NEC 430 to get a better
understanding.
>
>
>So let me ask you a question - would you connect your 220V tablesaw directly
>to the main breaker in your panel? Besides the code requirement for a
>branch circuit, and wire size, why not? Isn't it because circuits are sized
>to the application?
Maybe we should just tell people to follow the 240.4(D) rule (15a = 14ga, 20a
= 12 ga, 30a =10-ga) and ignore the 430 rules altogether since they seem to be
over everyone's head.
It just isn't what the code allows.
430 "motor" rules do require the circuit to be sized to the motor served.
"Greg" <[email protected]> wrote in message
news:[email protected]...
> >So let me ask you a question - would you connect your 220V tablesaw
directly
> >to the main breaker in your panel? Besides the code requirement for a
> >branch circuit, and wire size, why not? Isn't it because circuits are
sized
> >to the application?
>
> Maybe we should just tell people to follow the 240.4(D) rule (15a = 14ga,
20a
> = 12 ga, 30a =10-ga) and ignore the 430 rules altogether since they seem
to be
> over everyone's head.
> It just isn't what the code allows.
>
> 430 "motor" rules do require the circuit to be sized to the motor served.
Not at all Greg - I appreciate you mentioning the 430 rule - something I'm
not familiar with and can stand to learn from. My reply was more in
response to CW's condescending tone than it was related to anything factual
about electricity.
--
-Mike-
[email protected]
"CW" <no adddress@spam free.com> wrote in message
news:[email protected]...
> You do seem to have a bit of a comprehension problem. Breakers are sized
to
> protect the wiring. How many 350ma breakers do you have for electric
clocks?
> You must have a whole bank of them for individual light. Do you have a
> separate building to house all these?
> "Mike Marlow" <[email protected]> wrote in message
> news:Re%Vc.56$Y%[email protected]...
>
>
Unfortunately, it's you with the reading comprehension problem. If you
didn't suffer this you would have noted my original point. I'm done with
this now - you're a waste of time and not at all entertaining.
--
-Mike-
[email protected]
"Searcher" writes:
> I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was
only
> going to run it off our secondary clothes dryer feed (we no longer use
it).
> It would have been an easy hookup, but my electrician said that the 40A
> could possibly be too much for it. For the price of a new breaker I have a
> better piece of mind that I am not going to overload the motor with 40 A
> when it only requires 15A. So I gave it a 20A breaker/
That is a common misunderstanding of the relationship between a c'bkr and a
motor.
The c'bkr does NOT protect the motor, only the insulation on the wires
feeding the motor.
There are conditions where a 20A c'bkr will nuisance trip on a 5 HP motor.
If you truly want to protect the motor, you must add an overload relay.
HTH
Lew
> It would have been an easy hookup, but my electrician said that the 40A
> could possibly be too much for it.
I got a new shotgun. I'm only going to shoot at targets that are
close until it's broken in so I won't strain it.
DonkeyHody
"We should be careful to get out of an experience only the wisdom
that is in it - and stop there; lest we be like the cat that sits down
on a hot stove-lid. She will never sit down on a hot stove-lid
again---and that is well; but also she will never sit down on a cold
one anymore." - Mark Twain
You need to look at the plate on the motor to see how many amps it draws.
"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> I'm going to purchase a air compressor which as a 7hp rating so I guess
it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
>
> Regards
>
>
It's not intended to protect the motor.
"Robert Galloway" <[email protected]> wrote in message
news:[email protected]...
> Maybe what the electrician meant was that a 40 amp breaker wouldn't
> offer much protection. It would happily deliver enough amps for the
> motor to fry without tripping.
>
> rhg
>
> CW wrote:
>
> > If your electrician said that, fire him. Amperage draw is determined by
the
> > motor, not the breaker.
> >
> > "Searcher" <[email protected]> wrote in message
> > news:1V%[email protected]...
> >
> >>I have an Ingersol Rand 60 gal and it only draws 15 amps @ 240v. I was
> >
> > only
> >
> >>going to run it off our secondary clothes dryer feed (we no longer use
> >
> > it).
> >
> >>It would have been an easy hookup, but my electrician said that the 40A
> >>could possibly be too much for it. For the price of a new breaker I have
a
> >>better piece of mind that I am not going to overload the motor with 40 A
> >>when it only requires 15A. So I gave it a 20A breaker/
> >>
> >>Rich
> >>
> >>"Lew Hodgett" <[email protected]> wrote in message
> >>news:[email protected]...
> >>
> >>>"Woodchuck" writes:
> >>>
> >>>
> >>>>I'm going to purchase a air compressor which as a 7hp rating so I
> >
> > guess
> >
> >>>it's
> >>>
> >>>>really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> >>>>Question, how many amp breaker is needed and typically what current
> >
> > does
> >
> >>a
> >>
> >>>>compressor like this draw.
> >>>
> >>>Use a 2P-40A branch c'bkr and #8 AWG, 2 conductor /w/ ground to feed
the
> >>>compressor.
> >>>
> >>>It's what I've used for a 5HP, 2 stage unit for the last 10 years.
> >>>
> >>>HTH
> >>>
> >>>Lew
> >>>
> >>>
> >>>
> >>
> >>
> >
> >
>
"Woodchuck" <[email protected]> wrote in message
news:[email protected]...
> I'm going to purchase a air compressor which as a 7hp rating so I guess
it's
> really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
> Question, how many amp breaker is needed and typically what current does a
> compressor like this draw.
>
> Regards
>
>
You should be able to find the current specs from the vendor's web site. I
would not be surprised to see it hovering around 20A.
--
-Mike-
[email protected]
Ask the Vendor about the AMP rating of the motor is the only REAL way
to know
Frankly, if this is more than a real 3hp motor, I would be very
surprised
John
On Wed, 18 Aug 2004 21:35:22 -0400, "Woodchuck"
<[email protected]> wrote:
>I'm going to purchase a air compressor which as a 7hp rating so I guess it's
>really a 5hp compressor. My shop has a 40amp 240v feed to my subpanel.
>Question, how many amp breaker is needed and typically what current does a
>compressor like this draw.
>
>Regards
>