Hi,
I have to install a very long wiring run to a compressor. Here's the criteria:
1. approx 300ft from my main panel to the compressor
2. 220V motor, 1 phase, operating at 11.2amps at 10psi/60Hz.

Questions:
1. is #10 AWG sufficient? If so, how can I be sure (where could I check in the NEC to confirm)?
2. do I need to do a voltage drop calculation?
3. Will my motor burn out because it's so far from the main panel?
4. what size breaker is required?
5. would you recommend anything else? (i.e. maybe lighting protection because it's so far from the main house??)

All technical advice appreciated.
Thanks
Theodore

On Tuesday, July 21, 2015 at 1:06:45 AM UTC-5, wrote:
On Mon, 20 Jul 2015 22:36:10 -0700 (PDT), wrote:

Hi,
I have to install a very long wiring run to a compressor. Here's the criteria:
1. approx 300ft from my main panel to the compressor
2. 220V motor, 1 phase, operating at 11.2amps at 10psi/60Hz.

Questions:
1. is #10 AWG sufficient? If so, how can I be sure (where could I check in the NEC to confirm)?
2. do I need to do a voltage drop calculation?
3. Will my motor burn out because it's so far from the main panel?
4. what size breaker is required?
5. would you recommend anything else? (i.e. maybe lighting protection because it's so far from the main house??)

All technical advice appreciated.
Thanks
Theodore

Disregard my previous reply.
I am sorry I misread your question I thought you were saying 3000
feet.

10ga at 300 feet will drop about 8v. If you start with a true 240v,
you end up with 232 at FLA but the open question is whether you will
have enough to deal with the locked rotor to start it.
I have a 120v 1hp compressor and we couldn't get it to start reliably
at 150' with a 10ga cord.
You may end up with 8ga or larger to make this work.
8ga gets you 5v drop at 11a but we still need to know what LRA is to
decide.

Wouldn't aluminum SEU be cheaper than copper and do the same thing? If he had some poles he could string triplex. I've powered out buildings that way. o_O

[8~{} Uncle Wire Monster

wrote:
Hi,
I have to install a very long wiring run to a compressor. Here's the criteria:
1. approx 300ft from my main panel to the compressor
2. 220V motor, 1 phase, operating at 11.2amps at 10psi/60Hz.

Questions:
1. is #10 AWG sufficient? If so, how can I be sure (where could I check
in the NEC to confirm)?
2. do I need to do a voltage drop calculation?
3. Will my motor burn out because it's so far from the main panel?
4. what size breaker is required?
5. would you recommend anything else? (i.e. maybe lighting protection
because it's so far from the main house??)

All technical advice appreciated.
Thanks
Theodore

I'm using #10 for 85 feet. That's works ok. Its even 120volt probably more
current. Never measured. I don't know the hp rating of motor. It has a 3 hp
equivalent rating. The compressor may have a breaker specified. That said,
without calculation, your cutting it close.

Greg

On 7/21/2015 12:36 AM, wrote:


Plug ur numbers in and click to calculate ... 11.2 amps at 10 psi?
Probably ought to consider what it is at 150 psi.
http://www.electrician2.com/calculat...r_initial.html

Plug ur numbers in and click to calculate ... 11.2 amps at 10 psi?
Probably ought to consider what it is at 150 psi.
http://www.electrician2.com/calculat...r_initial.html

Sorry, I should have mentioned: it's a compressor for a pond aerator, so I don't expect very high pressure/load at all. Looks like an 8V drop over 300ft using this calculator. Is that something to be concerned about? I will TRY to find the Locked Rotor Amperes by contacting the manufacturer, but not hopeful. Any other suggestions?

On Tuesday, July 21, 2015 at 8:13:19 AM UTC-5, wrote:
Plug ur numbers in and click to calculate ... 11.2 amps at 10 psi?
Probably ought to consider what it is at 150 psi.
http://www.electrician2.com/calculat...r_initial.html

Sorry, I should have mentioned: it's a compressor for a pond aerator, so I don't expect very high pressure/load at all. Looks like an 8V drop over 300ft using this calculator. Is that something to be concerned about? I will TRY to find the Locked Rotor Amperes by contacting the manufacturer, but not hopeful. Any other suggestions?

I actually guessed that was the purpose of your compressor. The 10 psi tipped me off. ^_^

[8~{} Uncle Air Monster

On 07/21/2015 12:36 AM, wrote:
Hi,
I have to install a very long wiring run to a compressor. Here's the criteria:
1. approx 300ft from my main panel to the compressor
2. 220V motor, 1 phase, operating at 11.2amps at 10psi/60Hz.

Questions:
1. is #10 AWG sufficient? If so, how can I be sure (where could I check in the NEC to confirm)?
....

Agree w/ gfretwell that seems like awful big load for an aerator; how
about a link to the particular unit you're planning on?

Given the figures above, the motor-sizing table in my copy of Richter's
Wiring Simplified shows a #6 for 350-400 ft run 240V 2 and 1-1/2 hp,
respectively. That's based on a 1-1/2% drop calculation for motor vis a
vis the nominal 2% considered "standard" for other non-motor loads.

If this really isn't hard-starting, #8 would be marginal at 230-280 ft
max distance for the two motor ratings above.

W/O further details, looks like #6 to me although probably could get by
w/ #8. #10 is definitely too small for that size motor load...

--

Hi,
I have to install a very long wiring run to a compressor. Here's the criteria:
1. approx 300ft from my main panel to the compressor
2. 220V motor, 1 phase, operating at 11.2amps at 10psi/60Hz.

Questions:
1. is #10 AWG sufficient? If so, how can I be sure (where could I check in the NEC to confirm)?
2. do I need to do a voltage drop calculation?
3. Will my motor burn out because it's so far from the main panel?
4. what size breaker is required?
5. would you recommend anything else? (i.e. maybe lighting protection because it's so far from the main house??)

All technical advice appreciated.

#10 would probably suffice for the running load, but the starting load will be much greater. I would go with #8 copper wire. You should contact the manufacturer and see what they recommend for a wire size and a breaker.

Check out article 430

John Grabowski
http://www.MrElectrician.TV

On 07/21/2015 1:29 PM, dpb wrote:
....

Given the figures above, the motor-sizing table in my copy of Richter's
Wiring Simplified shows a #6 for 350-400 ft run 240V 2 and 1-1/2 hp,
respectively. That's based on a 1-1/2% drop calculation for motor vis a
vis the nominal 2% considered "standard" for other non-motor loads.

If this really isn't hard-starting, #8 would be marginal at 230-280 ft
max distance for the two motor ratings above.

W/O further details, looks like #6 to me although probably could get by
w/ #8. #10 is definitely too small for that size motor load...

at that distance.

--

Manufacturer FINALLY got back to me this evening!
It's 11.2 amps at 110V, so only 6 amps at 220V.
That said, I used the above website to calculate the voltage drop at 8volts over 300LF. This is 3.5%, which I beleive is quite acceptable.

I think I'm good, yes?

(all technical opinions greatly appreciated, especially dissenting ones)

On 07/21/2015 7:29 PM, wrote:
Manufacturer FINALLY got back to me this evening!
It's 11.2 amps at 110V, so only 6 amps at 220V.

That makes a lot more sense on the motor size. Now the question is, is
it a dual-voltage motor?

That said, I used the above website to calculate the voltage drop at 8volts over 300LF. This is 3.5%, which I beleive is quite acceptable.

I think I'm good, yes?

That's too much for a motor circuit if that's what you computed for the
running voltage; you'll be way under that during starting.

(all technical opinions greatly appreciated, especially dissenting ones)

The table again shows you can go 340-ft 240V for 1/2 hp w/ #10 but only
220-ft w/ #12 (which, w/o looking is what I'd guess the above voltage
drop would be for).

I'm saying you need #10.

--

On Tuesday, July 21, 2015 at 9:07:11 PM UTC-4, dpb wrote:
On 07/21/2015 7:29 PM, wrote:
Manufacturer FINALLY got back to me this evening!
It's 11.2 amps at 110V, so only 6 amps at 220V.

That makes a lot more sense on the motor size. Now the question is, is
it a dual-voltage motor?

That said, I used the above website to calculate the voltage drop at 8volts over 300LF. This is 3.5%, which I beleive is quite acceptable.

I think I'm good, yes?

That's too much for a motor circuit if that's what you computed for the
running voltage; you'll be way under that during starting.

(all technical opinions greatly appreciated, especially dissenting ones)

The table again shows you can go 340-ft 240V for 1/2 hp w/ #10 but only
220-ft w/ #12 (which, w/o looking is what I'd guess the above voltage
drop would be for).

I'm saying you need #10.

--

Yes, it's definitely a dual voltage motor.
Yes, you are correct in that my voltage drop calculation is incorrect (used the wrong current) and I just redid and found only a 4.5volt drop (2% drop).
Yes, I plan on going with #10.

Thank you, evereyone, VERY much for the advice, all of which was well-referenced and thought out.

On 07/21/2015 9:02 PM, wrote:
On Tue, 21 Jul 2015 20:07:01 -0500, wrote:

On 07/21/2015 7:29 PM, wrote:
Manufacturer FINALLY got back to me this evening!
It's 11.2 amps at 110V, so only 6 amps at 220V.

That makes a lot more sense on the motor size. Now the question is, is
it a dual-voltage motor?

That said, I used the above website to calculate the voltage drop at 8volts over 300LF. This is 3.5%, which I beleive is quite acceptable.

I think I'm good, yes?

That's too much for a motor circuit if that's what you computed for the
running voltage; you'll be way under that during starting.

(all technical opinions greatly appreciated, especially dissenting ones)

The table again shows you can go 340-ft 240V for 1/2 hp w/ #10 but only
220-ft w/ #12 (which, w/o looking is what I'd guess the above voltage
drop would be for).

I'm saying you need #10.

This sounds like a 1HP motor so I would go after that in your table.,

Realistically, it's likely 3/4 hp; the table for it would be 240-ft for
#10 so would also need #8 for 300 to be within the 1-1/2% drop range it
uses.

Seeing the nameplate for OP's actual motor would certainly reduce the
guesswork...

--

On 07/22/2015 8:12 AM, dpb wrote:
On 07/21/2015 9:02 PM, wrote:
On Tue, 21 Jul 2015 20:07:01 -0500, wrote:
....

The table again shows you can go 340-ft 240V for 1/2 hp w/ #10 but only
220-ft w/ #12 (which, w/o looking is what I'd guess the above voltage
drop would be for).

I'm saying you need #10.

This sounds like a 1HP motor so I would go after that in your table.,

Realistically, it's likely 3/4 hp; the table for it would be 240-ft for
#10 so would also need #8 for 300 to be within the 1-1/2% drop range it
uses.

Seeing the nameplate for OP's actual motor would certainly reduce the
guesswork...

As a last point (altho OP is likely long gone)...One can never go wrong
going up a size and just a quick survey showed #8-2 UF is 1.80/ft
whereas #10 is 1.60, 0.20/ft difference. That would translate into $60
for the run difference. Difference likely to be less than that in
quantity but if have no use for the extra and don't want to go to the
trouble of reselling the end, might choose to but the length needed...

--

On Wednesday, July 22, 2015 at 10:34:15 AM UTC-4, dpb wrote:

As a last point (altho OP is likely long gone)...One can never go wrong
going up a size and just a quick survey showed #8-2 UF is 1.80/ft
whereas #10 is 1.60, 0.20/ft difference. That would translate into $60
for the run difference. Difference likely to be less than that in
quantity but if have no use for the extra and don't want to go to the
trouble of reselling the end, might choose to but the length needed...

--
Wait... I'm still here! (the OP)
This photo is the _same_ model that I have:

http://yabe.chudov.com/Gast-1423-103...3/DSC_0031.JPG

It's a 1HP motor, but I can't understand much else from the sticker. Any additional advice or instruction appreciated. .

On 07/22/2015 8:33 PM, wrote:
On Wednesday, July 22, 2015 at 10:34:15 AM UTC-4, dpb wrote:

As a last point (altho OP is likely long gone)...One can never go wrong
going up a size and just a quick survey showed #8-2 UF is 1.80/ft
whereas #10 is 1.60, 0.20/ft difference. That would translate into $60
for the run difference. Difference likely to be less than that in
quantity but if have no use for the extra and don't want to go to the
trouble of reselling the end, might choose to but the length needed...

--
Wait... I'm still here! (the OP)
This photo is the _same_ model that I have:

http://yabe.chudov.com/Gast-1423-103...3/DSC_0031.JPG

It's a 1HP motor, but I can't understand much else from the sticker.
Any additional advice or instruction appreciated. .

OK, thanks....if it's really 300-ft, I'd definitely run #8. Doesn't
give LRA and I didn't try to find more detail spec's via the part no but
can't go wrong by the larger size as noted above. If nothing else,
it'll run a tad cooler and you won't need to worry about starting effort
shortening life by being marginally under-voltage.

--

wrote in message
...
Wait... I'm still here! (the OP)
This photo is the _same_ model that I have:

http://yabe.chudov.com/Gast-1423-103...3/DSC_0031.JPG

It's a 1HP motor, but I can't understand much else from the sticker. Any
additional advice or instruction appreciated. .

The motor is 1 HP. If wired for 115 volts it takes 23 amps and if 230 volts
it takes 6.5 amps.

If ran on 60 hz it runs at 1723 rpm and if 50 hz 1425 rpm.

It has a thermal switch inside so if it gets too hot it will stop and when
it cools down it can be restarted.

On 07/22/2015 9:44 PM, dpb wrote:
On 07/22/2015 8:33 PM, wrote:
....


It's a 1HP motor, but I can't understand much else from the sticker.
Any additional advice or instruction appreciated. .

OK, thanks....if it's really 300-ft, I'd definitely run #8. Doesn't give
LRA and I didn't try to find more detail spec's via the part no but
can't go wrong by the larger size as noted above. If nothing else, it'll
run a tad cooler and you won't need to worry about starting effort
shortening life by being marginally under-voltage.

OBTW, you could put a remote disconnect and then run #10 to the actual
connections. It (the wiring, not the motor that has its own) can be
protected at the local with just a disconnect remote/near the motor if
it's sized for the ampacity of the load which 10 will carry; you just
need the larger in this case because it's a motor to avoid the voltage
drop for startup.

--

wrote:
Plug ur numbers in and click to calculate ... 11.2 amps at 10 psi?
Probably ought to consider what it is at 150 psi.
http://www.electrician2.com/calculat...r_initial.html

Sorry, I should have mentioned: it's a compressor for a pond aerator, so I don't expect very high pressure/load at all. Looks like an 8V drop over 300ft using this calculator. Is that something to be concerned about? I will TRY to find the Locked Rotor Amperes by contacting the manufacturer, but not hopeful. Any other suggestions?


I may be way off base here, but have you looked into keeping the
compressor close to the power source and running 300 feet of air line to
the aerator?

This company says their aerators can be operated with 1,000 ft of air
tubing.

http://tinyurl.com/pdc4wet

Jeff


--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

Not practical in my case... i'm feeding 4 aerator heads from this one compressor. That would be a lot of hose spidering off in many directions.

Besides, my calcs show the voltage drop to be very small; the running current is 6amps meaning startup current is maybe 18amps (well within a 10awg breaker's capacity), and (unless I'm missing something) no respondant has raised a serious technical concern.

-Theodore.