It's probably that the synthetic oil did it. Although if I rewired it for 10 gauge I would just buy a 30 amp breaker because they are cheap. One issue too is you can't just buy 3 feet of wire, you have to buy 15 ft and locally that is around $20.
120v 1.8hp trips CB close to panel, but not further away, electrical q's
- Thread starter pipsters
- Start date
It's probably that the synthetic oil did it. Although if I rewired it for 10 gauge I would just buy a 30 amp breaker because they are cheap. One issue too is you can't just buy 3 feet of wire, you have to buy 15 ft and locally that is around $20.
Outlawmws
Well-known member
It absolutely does matter, but certainly if you had it wired correctly on the dedicated outlet its not the issue. Now a key question is anything inside the Comp switch basackwards? All factory? or have you moved/replaced anything?
Have you have a chance to (or have toy the test gear) to setup a meter on the circuit and fire the compressor? seen what voltage drop was on it?
sberry
Banned
Synth oil is a fine idea, might help a bit but we been over this wire breaker size a dozen times in this thread. I tried my best to keep it as simple as possible. Even used simple logic to the point that if you don't know anything about it that one should be able to reason their way thru this.
No nothing has changed. I can't test the voltage while compressor is running but get around 122 when not. Again, 3 different circuits with their own breakers NEAR the panel are doing this, when you bring it around to the back of my house or side of my house and plug it in it's fine. I *highly doubt* out of 5 different circuits, 3 are bad and 2 are good and they just happen to be further away. Let's think about this logically.
Unfortunately I'm already using synthetic...and even in the summer (90F temps) the compressor did this. That thought went thru my head but unfortunately I it does not pertain in this case.
I really appreciate your help. All I'm asking is for a citation from some governmental or industry agency that says using a 30 amp breaker is OK, and how exactly to do it (ie 30 amp, 10 gauge, 20 amp recep, 30 amp 12 gauge, 20 amp recep, etc.).
I understand the logic behind it. I thought about it before posting. But all the research I did said not to do that. Please, I'm just looking for some official info so I can do it right and sleep at night.
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Outlawmws
Well-known member
Here are two new thoughts:
Is the "Good" CB on a) the same side as the "bad" CB's or is it up high near the mains?
CB panels should have the highest amperage breakers nearest the mains connection to keep the buss bars from getting overloaded.
If it is a one side vs. the other side, then one Buss bar might be fried and causing a resistive load.
Can you temporarily swap the single wire breaker out and put the dedicated breaker in it's place? Then test fire the Comp.
If it is one side vs. the other try the dedicated breaker in the other side.
Is the "Good" CB on a) the same side as the "bad" CB's or is it up high near the mains?
CB panels should have the highest amperage breakers nearest the mains connection to keep the buss bars from getting overloaded.
If it is a one side vs. the other side, then one Buss bar might be fried and causing a resistive load.
Can you temporarily swap the single wire breaker out and put the dedicated breaker in it's place? Then test fire the Comp.
If it is one side vs. the other try the dedicated breaker in the other side.
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RustFarmer
Well-known member
I've plugged the compressor into the same circuit that pops with an extension cord and plugged the compressor into 15 amp circuits far away from the breaker itself and it works as it should.
That makes sense. I will have to look. However why would plugging in a 25' extension cord allow the compressor to operate as it should then plugging directly into the outlet have it pop? It should be the opposite if what you are saying is true (ie not getting enough power, problem seems to be too MUCH power).
tyyost
Well-known member
Ok, after 5 pages I have come to one conclusion. You want a free technical diagnosis without wanting to do a whole lot. You got several, including a highly technical one about impedance. You want someone to reason this into working for you.
Truth is, unless you get an amp clamp and dosome real tests you won't get a reason looking online.
I would comfortably run the 30 amp breaker. If you are ok with a 25' cord on the compressor I can't see why that would bother you. Round here every big box sells wire by the foot. If you are bothered buy some 10 gauge and re do the install. I am sure that the "cheap" 30 amp breaker would be a safe way to test the issues. If that kicks then there is a few more things to be done.
Sberry gave you great advice on the first page. I know you want a why, and we tried to help. Truth is all electric motors vary. You were asked questions you couldn't answer about the comp and motor. High quality motors sometimes run cleaner, depends. Remember, sometimes you get what you pay for. This holds true in online advise, air compressors and electrical work.
Truth is, unless you get an amp clamp and dosome real tests you won't get a reason looking online.
I would comfortably run the 30 amp breaker. If you are ok with a 25' cord on the compressor I can't see why that would bother you. Round here every big box sells wire by the foot. If you are bothered buy some 10 gauge and re do the install. I am sure that the "cheap" 30 amp breaker would be a safe way to test the issues. If that kicks then there is a few more things to be done.
Sberry gave you great advice on the first page. I know you want a why, and we tried to help. Truth is all electric motors vary. You were asked questions you couldn't answer about the comp and motor. High quality motors sometimes run cleaner, depends. Remember, sometimes you get what you pay for. This holds true in online advise, air compressors and electrical work.
lwlobo
Well-known member
Like most say, putting in a 30A breaker would solve the problem and would be kosher for a dedicated circuit.
If you really want to solve the problem without any exceptions (whether allowable or not), get a 30A breaker, 10ga wire and a 30 amp 110 outlet and plug (I might have a remnant I'd sell you). Might cost you $30 total. I did this at my old place for my travel trailer, the 30A is common stuff for RV's. Can find everything you need at your local HD or electrical supply place or an online RV supply place, etc. Then it won't trip and you can feel comfortable its all to the letter of the code.
I hate it when circuits trip, it means something wasn't done right. Fix it and forget it.
If you really want to solve the problem without any exceptions (whether allowable or not), get a 30A breaker, 10ga wire and a 30 amp 110 outlet and plug (I might have a remnant I'd sell you). Might cost you $30 total. I did this at my old place for my travel trailer, the 30A is common stuff for RV's. Can find everything you need at your local HD or electrical supply place or an online RV supply place, etc. Then it won't trip and you can feel comfortable its all to the letter of the code.
I hate it when circuits trip, it means something wasn't done right. Fix it and forget it.
Yes, but you do realize that the various explanations are contradictory, right?
I reasoned why the compressor was doing what it was, and I have people asking me to get (admittedly difficult) measurements which are completely unneeded.
The technical explanation was spot on and, while I could not articulate in correct wording, that is what I was guessing was happening as well.
We've moved on.
I don't care what others are comfortable doing. I care what is legal and also safe. I just wanted a link that shows that I am allowed to run a 30 amp breaker that sberry is advocating I do (which I agree with, and will, if I can do it legally using a 20 amp receptacle). The fact that no code apparently allows for this that anyone can link to tells me all I need to know. Thanks for the help.
P.S. If we all operated with the mentality of "doing what we are comfortable with" we'd have a lot more BP oil disasters.
Yeah that is what I'm thinking, although it would just be a lot easier to buy a 10' or 25' 12g extension cord. Is there a way I can create an adapter, and keep the 120v plug on my compressor and plug that into another plug that plugs into the 30 amp recep? Kinda like a 3/8" -> 1/2" adapter?
Any issues with running an extension cord in this scenario? Obviously more than enough power is getting to the compressor.
lwlobo
Well-known member
Yes, you can use an adapter, but why are you willing to put in a hokey adapter so you can use a 15amp plug on a 30A circuit when you're unwilling to put in a 30A breaker on the existing circuit? The 30A breaker on the existing circuit is a more fundametally sound solution, IMO.
BTW, I've seen those adapters melt under decent load. I strongly recommend doing everything 30A or putting the 30A breaker on the existing circuit and dedicating it. Using an extension cord or adapter plug is a shoddy solution.
Well from my understanding the breaker is just simply to protect the wiring and receptacle from over current and possibly starting a fire. I guess I wasn't really thinking it would be a problem, but apparently it is!! Haha. I bought a 120v compressor to be portable so I didn't want to limit it's use to just that one plug.
If you've seen them melt then that is definitely a big deal. So no on the adapter.
I am all about throwing a 30 amp breaker in there, I just wanted something I could look up online stating I was allowed to do it. I'm not against doing it, people keep saying I am and nowhere have I written that.
Also, stupid question, but why would an extension cord be bad? Isn't that just using the same wiring that is in your home? So one plug could have 50' of 14 gauge wire run to it before plugging in (say my back yard 15 amp outlet) while the other has 3' of wire to the outlet but a 10' 12g extension cord, and that would be considered bad?
Ok some quick questions.
1.8 hp electric motor. Convert to watts = 1342 watts (745.7 * 1.5)
1342 watts / 120 volts = 11.2 amps.
So, is that correct? The motor *should* be drawing 11.2 amps while running continuously? (obliviously higher on startup).
In that case even 14 gauge 15 amp plug should be OK and not overheat the motor. So I would assume a dedicated 20 amp line with 12g wire run 3' from the breaker and a short 10' to 25' extension cord should allow the compressor to draw plenty of juice and not overheat the motor, correct?
I did take off the top of the motor and there are two capacitors on there. This is all greek to me because I'm not really sure what I'm reading or looking for. Looks like they are easy to just unplug and replace. Could I possibly get a heavier duty one, or would that maybe damage the motor?
1.8 hp electric motor. Convert to watts = 1342 watts (745.7 * 1.5)
1342 watts / 120 volts = 11.2 amps.
So, is that correct? The motor *should* be drawing 11.2 amps while running continuously? (obliviously higher on startup).
In that case even 14 gauge 15 amp plug should be OK and not overheat the motor. So I would assume a dedicated 20 amp line with 12g wire run 3' from the breaker and a short 10' to 25' extension cord should allow the compressor to draw plenty of juice and not overheat the motor, correct?
I did take off the top of the motor and there are two capacitors on there. This is all greek to me because I'm not really sure what I'm reading or looking for. Looks like they are easy to just unplug and replace. Could I possibly get a heavier duty one, or would that maybe damage the motor?
lwlobo
Well-known member
The reason putting extra cord length in the ciruit isn't ideal is because you're deliberately introducing increased resistance. This resistance will cause your compressor to have lower available voltage while running (there will be a voltage drop in the cord) and will reduce power and may reduce the life of your compressor.
In reality, all of these solutions will work and none of them are likely to cause you any problems.
To ease your conscience see what machine design says on the topic here.
Search for "common" and read that paragraph.
"...Even the NEC allows oversizing within prescribed limits"
Google is your friend, with a little effort you might even find the actual NEC guidelines. Then put in the 30A breaker and be done with it.
In reality, all of these solutions will work and none of them are likely to cause you any problems.
To ease your conscience see what machine design says on the topic here.
Search for "common" and read that paragraph.
"...Even the NEC allows oversizing within prescribed limits"
Google is your friend, with a little effort you might even find the actual NEC guidelines. Then put in the 30A breaker and be done with it.
Outlawmws
Well-known member
If fit works with the extension cord, and the cord, and more importantly the plugs (highest resistance points), are not getting warm, it's probably fine to use the cord. But I think you are masking a problem elsewhere. Possibly the caps out of spec, possibly the motor is defective in some way. If so, eventually the compressor will tell you, but by then, it will be to late...
Yeah I'm been trying to google, but I'll be honest I know absolutely nothing about the subject and it's pretty hard weeding through it. Thank you for the link and info.
porcupine73
Well-known member
The two missing factors here are power factor and efficiency. Some of this info may be on the nameplate. I.e. .95 efficiency, .8 power factor. In that case it would be 11.2 amps / .95 / .8 = 14.7 amps. One of those caps in there is probably a power factor correction cap to bring the power factor close to unity or possibly slightly leading.
It's also possible if the service factor is say 1.15 or something, that they may be drawing more than 1.8 HP out of it in the compressor, since usually they bargain on it being an intermittent load.
Induction motors are often modeled as constant KVA devices, that is to say, if they are getting below nominal voltage, to a point, they will draw more current to make up for it.
gary300
Well-known member
Just to answer the original question, adding wire length adds some resistance to the circuit which will limit the inrush current of the motor so the breaker does not trip. With a short wire distance there is not much resistance so the inrush current is greater so the breaker trips. I would say that the breaker is just on the verge or tripping with a longer wire run, then when the run is shorter it is just enough additional current flow to get the breaker to trip.
kythri
Well-known member
To the folks with the electrical know-how: If a 30A breaker is a legit install, and doesn't violate any code, can you cite the code for pipsters? It sounds like he'd be willing to do this, he just wants the code verification, for a valid reason.
I'm willing to play a little more fast and loose because I don't believe it's an issue, and I trust what I've been told by people I trust that it's an OK thing to do, but I totally understand pipsters reluctance to do something without seeing firsthand the electrical code that allows this.
If it is truly in the code, it shouldn't be something hard to cite, should it? The bigger breaker resolution sounds like it will fix all of his technical issues, and citing the code allowing the bigger breaker would resolve his hesitance.
I'm willing to play a little more fast and loose because I don't believe it's an issue, and I trust what I've been told by people I trust that it's an OK thing to do, but I totally understand pipsters reluctance to do something without seeing firsthand the electrical code that allows this.
If it is truly in the code, it shouldn't be something hard to cite, should it? The bigger breaker resolution sounds like it will fix all of his technical issues, and citing the code allowing the bigger breaker would resolve his hesitance.
Alchymist
Well-known member
2005 NEC here: (good luck finding the applicable section!)
http://www.brunswickcountync.gov/Portals/0/bcfiles/Building_Codes/bldinsp_2006_NC_Code_Handbook.pdf
Charles (in GA)
Well-known member
It has to be a dedicated motor circuit; cord and plug connected on a general purpose branch circuit doesn't get to take advantage of the special rules.
NEC 430 covers this.
Charles
NEC 430 covers this.
Charles
Charles (in GA)
Well-known member
I'm surprised they (Brunswick County, NC) have been able to get away with posting this on the internet. NFPA jealously protects their copyrighted publications and doesn't allow for this. Guess NFPA hasn't discovered it yet.
Charles
kythri
Well-known member
It's possibly legal if it's older. I ran into this a bit when looking a couple years ago. If the NFPA/NEC text is codified as law/ordinance, then the text can be legally reproduced.
This is why you're able to find older code available for free online, but newer stuff isn't, as it's use may be mandated, but the text isn't the actual law.
Greatbear
Well-known member
Is the breaker marked "HACR"? If not, it might be too sensitive to temporary overloads. HACR (heating, air conditioning, refrigeration) breakers are designed for motor starting duty and have a slight time delay built in to allow for motor starting with heavy inertial loads. Since an induction motor like the one you are using can draw 5-10 times its normal running current when starting, the second or so of starting time will trip a sensitive breaker immediately. It's worth checking out.
Provincial
Well-known member
Here is an "outside the box" thought brought on by Greatbear's post: if you don't have a HACR breaker, and cannot get one in single pole, consider installing a two-pole 20A HACR breaker in the bottom slots. You may have to shift some other breakers upward to clear the spot above, but from the photos posted earlier you have an open slot on the bottom of the panel, at least on the right side. If you can swap the positions of the existing breakers to put the one currently in use just above that empty slot, it makes room for the 2-pole breaker. You would want to tighten down the screw on the empty pole of the 2-pole breaker to remind you not to use the second pole, since it is tied to the other pole at the handle.
MrMark
Well-known member
I gave you the cite a long time ago pages back. This is not some big deal. It is a simple matter of putting the correct 30 amp breaker on the motor circuit.
Here's your cite:
430.52(A), (B), (C), Table 430.52.
It lets you multiply your motor full load current by 250 percent to get your maximum breaker size. You can even go up to 400 percent in some cases.
You are getting a lot of wild tangents in this thread. Stick to the basics as Sberry showed you in the very beginning.
Here's your cite:
430.52(A), (B), (C), Table 430.52.
It lets you multiply your motor full load current by 250 percent to get your maximum breaker size. You can even go up to 400 percent in some cases.
You are getting a lot of wild tangents in this thread. Stick to the basics as Sberry showed you in the very beginning.
MrMark
Well-known member
I also didn't get your comment about the wiring of the neutrals (I think) you said you put it on the opposite side (because it wouldn't matter you thought?)? It all looked correct to me. What were you talking about? Your strip lengths are pretty sloppy and I don't believe on that particular plug that you are suppose to wrap around the screw like a cheap receptacle. That GFCI has backwire that is a pressure clamp. You are supposed to use that, not the side screws. But, this has nothing to do with your little issue.
OK went to HD and bought a 30 amp 120v breaker. Installed and the compressor turns over perfectly and doesn't trip.
So now my setup is this:
30 amp breaker -> 12 gauge wire -> 20 amp GFCI 2 plug outlet -> Air Compressor
Unfortunately when I google the NEC 430 section above I don't get any guidance on exactly what to use/how to note. I was thinking of taping a piece of masking tape over the second outlet and writing "Air compressor only" or something. Would that suffice?
Thanks to everyone including MrMark, sberry, Charles, Alchymist, Outlawmws, lwlobo, dwm, TheGrooveKing and the gentleman from Europe with the technical aspects.
So now my setup is this:
30 amp breaker -> 12 gauge wire -> 20 amp GFCI 2 plug outlet -> Air Compressor
Unfortunately when I google the NEC 430 section above I don't get any guidance on exactly what to use/how to note. I was thinking of taping a piece of masking tape over the second outlet and writing "Air compressor only" or something. Would that suffice?
Thanks to everyone including MrMark, sberry, Charles, Alchymist, Outlawmws, lwlobo, dwm, TheGrooveKing and the gentleman from Europe with the technical aspects.
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Ah Ok so I should just put the wire going into it like the CB then? I will do that from now on.
I attached the neutral to the left side of the bank vs. the right side where the CB is.
MrMark
Well-known member
All correct, and you are correct, that has absolutely no effect. They are tied together by a common metal bar. Use whichever side allows the cleanest install. I put two ground bars in on opposite sides for the same reason.
On your strip lengths make sure you use the breaker strip guide, you shouldn't have that exposed copper showing like that on your breakers. Tidy electrical work is good electrical work.
On your strip lengths make sure you use the breaker strip guide, you shouldn't have that exposed copper showing like that on your breakers. Tidy electrical work is good electrical work.
MrMark
Well-known member
I would like you to someday get an amp clamp, doesn't have to be the best, and clamp that wire and revive this thread to report your steady state current draw. It may be a little high. Let's see what it is. To be code, the wire should be rated for 125 percent of full load amps.
My compressor has a 15 amp rating on the motor, so 125% of 15 amp would be 18.** give or take, correct?
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MrMark
Well-known member
You should put a cover over the unused reptical, like to protect for kids, and get a label on the in use outlet. "Dedicated Outlet, Breaker Sized for Motor Start, not for general use."
MrMark
Well-known member
It is embossed right on that Hom breaker. Every electrical device should have a strip gauge.
Sounds official thank you