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Discussion Starter · #1 ·
I am installing a 220 outlet for a compressor--I thought I would be "extra safe" and install GFCI breaker in the panel--the outlet calls for #10 wire--- hot red one, hot black one and a ground--all #10---no neutral. The GFCI 20 amp 2 pole breaker ---murry--- that I bought has a white coiled neutral wire and a place to land 3 wires---hot + hot and neutral. I have no neutral!--I believe that red hot goes to one post and black hot goes to one post and ground goes to the grounding bar--so I have no wire to land on the third post---the "Neutral post"!
Do I have the wrong GFCI or will it work as I have described?--Should I connect the white coiled wire off the GFCI breaker to the neutral bar?
Thanks for your expertise!!!
 

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GFCIs protection is not required, but if you would like to add one that will be ok.

The GFCI doesn't need a load neutral if the equipment does not have one. However the line neutral, that being your pig tail white coiled wire will need to be connected to the neutral bar since the breaker needs 120 volts for the electronics to work.

Connect the ground to the ground bar as you normally would.
 

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What size circuit does the compressor require.
You said #10 wire, which may mean the 20 amp breaker is too small anyway.
 

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Discussion Starter · #5 ·
Jump-Start--thank you--I do know that it is not required but I want to be extra safe as the panel and the outlets are outside.
JB--Nice catch!!!
I checked and you are correct--so now I have another delima---I have a 220 outlet in my garage--that is what I am duplicating off a new sub panel--for a RV garage--I copied all aspects of the existing outlet--
1. L6-30R outlet
2. Researched wire requirement--shows #10-Hot+Hot+Ground
3. Checked existing Breaker--Bryant non GFCI--"20 AMP"!!!!!---This is WRONG?--but it is why I bought the 20 amp Murray GFCI breaker!---I still know where my electrician lives--should I harass him?

So since it has not popped in 30 years here should I swap out the 20 amp for a 30 amp brea:eek:ker?--Or stay with the 20?

The compressor does not say "Amperage" it says --115 or 230 by a switch--I have always used it at 230--I have pictures I will see if I can upload them here--but thanks so far to each of you!
David
 

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Rob
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I am installing a 220 outlet for a compressor--I thought I would be "extra safe" and install GFCI breaker in the panel--the outlet calls for #10 wire--- hot red one, hot black one and a ground--all #10---no neutral. The GFCI 20 amp 2 pole breaker ---murry--- that I bought has a white coiled neutral wire and a place to land 3 wires---hot + hot and neutral. I have no neutral!--I believe that red hot goes to one post and black hot goes to one post and ground goes to the grounding bar--so I have no wire to land on the third post---the "Neutral post"!
Do I have the wrong GFCI or will it work as I have described?--Should I connect the white coiled wire off the GFCI breaker to the neutral bar?
Thanks for your expertise!!!
I don't see any wattage on that compressor but that breaker should work. IF it trips you will have to check all wires on that circuit for breaker size.
 

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Discussion Starter · #9 ·
Thanmks again guys--I have one more question--if I haven't run your patience dry yet!

I have red--black and green--#10 wire stranded--
-at the breaker end--red is hot---black is hot and green goes to ground (at the sub panel) --not neutral as discussed.
At the outlet end I have red to "Y"---Black to "X" and green to Ground--grounded to the receptical and the box (it is metal) it is in.

I am not an electrician but why don't I need a neutral for this outlet?--Just looking for an education--I know the receptical itself only has 3 posts.---why doesn't it have 4 posts?
 

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Jump-Start--thank you--I do know that it is not required but I want to be extra safe as the panel and the outlets are outside.
JB--Nice catch!!!
I checked and you are correct--so now I have another delima---I have a 220 outlet in my garage--that is what I am duplicating off a new sub panel--for a RV garage--I copied all aspects of the existing outlet--
1. L6-30R outlet
2. Researched wire requirement--shows #10-Hot+Hot+Ground
3. Checked existing Breaker--Bryant non GFCI--"20 AMP"!!!!!---This is WRONG?--but it is why I bought the 20 amp Murray GFCI breaker!---I still know where my electrician lives--should I harass him?

So since it has not popped in 30 years here should I swap out the 20 amp for a 30 amp brea:eek:ker?--Or stay with the 20?

The compressor does not say "Amperage" it says --115 or 230 by a switch--I have always used it at 230--I have pictures I will see if I can upload them here--but thanks so far to each of you!
David
Technically, you need a 30 amp, however, since you have a motor that doesn't go over 20 amps it will be functionally correct.

A 30 amp breaker however will cover nuisance tripping if someone plugged in a 30 amp device in the future.
 

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Rob
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Thanmks again guys--I have one more question--if I haven't run your patience dry yet!

I have red--black and green--#10 wire stranded--
-at the breaker end--red is hot---black is hot and green goes to ground (at the sub panel) --not neutral as discussed.
At the outlet end I have red to "Y"---Black to "X" and green to Ground--grounded to the receptical and the box (it is metal) it is in.

I am not an electrician but why don't I need a neutral for this outlet?--Just looking for an education--I know the receptical itself only has 3 posts.---why doesn't it have 4 posts?
It is the older type.
 

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Thanmks again guys--I have one more question--if I haven't run your patience dry yet!

I have red--black and green--#10 wire stranded--
-at the breaker end--red is hot---black is hot and green goes to ground (at the sub panel) --not neutral as discussed.
At the outlet end I have red to "Y"---Black to "X" and green to Ground--grounded to the receptical and the box (it is metal) it is in.

I am not an electrician but why don't I need a neutral for this outlet?--Just looking for an education--I know the receptical itself only has 3 posts.---why doesn't it have 4 posts?

If this device has no 120 volt loads, it doesn't need a neutral. Only 2 hots and a safety ground will do here. When one has 2 hots from a standard residential service you get 240 volts potential between them. 120 volts to neutral. Voltage is present and current will flow. between the hots at 240 volts. So if only 240 volts are needed then 2 hots will suffice. A neutral would have no function. However if say that motor also had a 120 volt work light or controls only then would neutral be needed. Neutrals are only needed where 120 volt loads are present.

A dryer has 240 volt heaters and a 120 volt motor; so it will need 2 hots, a neutral and a ground. An A/C on the other hand, or heater only has 240 volt parts and nothing requiring 120 so only 2 hots and a ground.


To keep it simple the neutral is only for something needing 120 volts, be it a table lamp or a 120 volt part like a control board in a 240 volt appliance.
 

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Thanmks again guys--I have one more question--if I haven't run your patience dry yet!

I have red--black and green--#10 wire stranded--
-at the breaker end--red is hot---black is hot and green goes to ground (at the sub panel) --not neutral as discussed.
At the outlet end I have red to "Y"---Black to "X" and green to Ground--grounded to the receptical and the box (it is metal) it is in.

I am not an electrician but why don't I need a neutral for this outlet?--Just looking for an education--I know the receptical itself only has 3 posts.---why doesn't it have 4 posts?
Boy Dave... Understand exactly where you are coming from and respect that interest.....

In laymen's terms, your residential system has two hot legs, as you understand. The voltage potential between those two hot legs is 240V.

But our US/NorthAmerica systems use predominately 120 V.... and electrically that is done with tapping into the transformer with a third wire we refer to as the neutral.

Either leg, to that neutral, results in a 120 V potential.
One leg to the other, results in a 240 V potential.

In your case, your compressor does not require any 120 V potential, thus you do not need that neutral wire.

Now, if it was your stve, with a light and a clock that runs on 120V, you would need that neutral.

Your ground wire, meerly is a safty measure, in case a wire shorts to the frame of your compressor, your current will run down that ground, exceeding your breaker Amperage, and trip. This is preferable to you touchingyour compressor, and that shorted compressor frame running thru you.

Basically, your compressor does not need 120V, thus you do not need a neutral.

Probably someone can explain that better.... it's Friday happy hour...

Best
 

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Rob
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Boy Dave... Understand exactly where you are coming from and respect that interest.....

In laymen's terms, your residential system has two hot legs, as you understand. The voltage potential between those two hot legs is 240V.

But our US/NorthAmerica systems use predominately 120 V.... and electrically that is done with tapping into the transformer with a third wire we refer to as the neutral.

Either leg, to that neutral, results in a 120 V potential.
One leg to the other, results in a 240 V potential.

In your case, your compressor does not require any 120 V potential, thus you do not need that neutral wire.

Now, if it was your stve, with a light and a clock that runs on 120V, you would need that neutral.

Your ground wire, meerly is a safty measure, in case a wire shorts to the frame of your compressor, your current will run down that ground, exceeding your breaker Amperage, and trip. This is preferable to you touchingyour compressor, and that shorted compressor frame running thru you.

Basically, your compressor does not need 120V, thus you do not need a neutral.

Probably someone can explain that better.... it's Friday happy hour...

Best
That was perfect.
 

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FLA = 18.6 A
So 20A outlet is fine !

:thumbsup:

That higher number is for single phase 120 VAC I believe, the 240 VAC single phase FLA is 9.3 amps.

Depends on starting/inrush current, inrush for a compressor can be very high, typical motor can be 4-10 times, with a compressor it can be as high as 12 times possibly more.

Assume worse case and you have 9.3 X 12=111 amps, a typical 20 amp molded case instantaneous operation is 6-10 times the rating, 6 x 20 =120 amps, placing the motor at or close to tripping on startups. While this may not happen on every startup it is a possibility.
 

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?

9.3 x 1.25 = 11.6 15 amp

tp motor protected no more than 250%

9.3 x 2.5 = no more than 23.25 so 20 amp, 15 should work


18.6 x 1.25 = 23.23

18.6 x 2.5 = no more than 46.5 so 40 amp, unless you can find a 45. 30 should work.

Inrush? where's the inrush calculation?
 

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Discussion Starter · #19 ·
You guys are terrific!---no wonder you always got paid more than me (Carpenter)--until I made Supe---I figured out FLA on my own---sorry if I got you started on FLA vs in rush--I am going to see if HD will swap my breaker--for a 30 amp--GFCI--to eliminate the possibility that down the raod someone thinks the outlet should handle 30 amps (L6-30R)
Thanks again for you time
Dave Mc
 

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You guys are terrific!---no wonder you always got paid more than me (Carpenter)--until I made Supe---I figured out FLA on my own---sorry if I got you started on FLA vs in rush--I am going to see if HD will swap my breaker--for a 30 amp--GFCI--to eliminate the possibility that down the raod someone thinks the outlet should handle 30 amps (L6-30R)
Thanks again for you time
Dave Mc
Hold on.

at what voltage?

30 amp protection (protecting the motor, not the circuit) at 240v is too high.

15 or 20 amp.


30 amp 120 v protects the motor, but your receptacle would be wrong.

you have to hots and ground, you would need hot,neutral,ground (if they make one) or switch that's rated.

I'd suggest the 240 v. (go for the 20 )
 
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