Correct breaker size for 15A compressor?

[sberry]

This is a good thread except for a couple bumps. The idea is to understand some of the fundamental principle of circuit design. The direct answers the op got here are safe and allowed.

 

[wyliesdiesels]

you will get shot down every time on this
max load on a 15 amp circuit is 12A.
need to go by nameplate rating not your calculated HP one.

That 80% rule only applies to continuous loads... a non continuous load can be 100% of circuit ampacity...

Once again this has nothing to do with a code book, no work is being done here that requires an inspection.

That depends on the AHJ...regardless, if one doesnt have a code book then how do they know what is to code?

codebooks are designed for wire pulling apes who memorizes the little bits and pieces that might affect the passing inspection from some other monkey. "ours not reason why, just to do and die." . Perhaps your brain shuts down when reciting code. "over my head" wow yer a legend in your own mind. I probably forgot more about electricity than you've ever known.

LMAO talk out of your *** much?

A codebook doesnt tell someone how to pull wire...

And BTW the guy you were responding to is an engineer so i doubt you know more than him.... but keep running your mouth like you know it all..

 

[Infinia]

That depends on the AHJ...regardless, if one doesnt have a code book then how do they know what is to code?

da code da code, for the third and final time what does this thread have to do with code? You obviously don't have a clue whats going on regards to the OP question. Continuously steering the conversation to 'the code', its pretty clear to me what's going on here, spreading FUD. The only thing that stands out, is how very strange it is that no attention is given to actually helping the OP. BUT you clowns put so much focus on how wrong everyone else is and how you since have a code book that only you are qualified to give advise.
what is this, tag team beat down with code books.

LMAO talk out of your *** much?

A codebook doesnt tell someone how to pull wire...

No one ever said that it did? Its obvious you make that **** up to make it seem like you are winning some kind of debate. If that's called talking out of your ***, you must be right since your the expert at it.

And BTW the guy you were responding to is an engineer so i doubt you know more than him.... but keep running your mouth like you know it all..

No you guys are the know it alls around here, that is why so much energy is focused on trying to beat down others. Stop talking badly about people and help the OP>
ohhh I'm really impressed. You might doubt it, but once again you don't really know what you don't know, right. BTW Anyone can say they are an engineer even trash men are "sanitation engineers". The only intellectual chops ive seen from him in this thread is that he reads the code book. haha

 

[mm08822]

The OP’s question was clearly answered in post 5, reconfirmed in post 10 and several other instances. Clearly his need has been addressed as he successfully accomplished the task reported in a parallel thread last night.

This thread has clearly taken a deep dive and shows a how a little bit of knowledge can be greatly embellished and potentially dangerous in/from the wrong mind/mouth. It is clearly a waste of time continuing to read this and even more so to reply feeding into a troll looking for an audience.

I will PM the moderators and ask to shut this circus stage down. We all have better things to do.

 

[Norcal]

Sounds like a good idea I deleted my comment.

 

[Infinia]

The OP question was answered even before he started this thread. Somehow I predicted a clusterf**k would be the result BEFORE the OP said he was headed over here to this side of the forum , clearly that was the case before the post count here had risen to 45. link to the original thread. )

https://www.garagejournal.com/forum/showthread.php?p=6633423#post6633423

Yes, that new thread has been a little bit of a trainwreck lol. I'm not bringing anything up to code. The house is a tear-down and will be after my mom sells it. I just need something to suit my needs that won't start on fire or shock anyone

.


And yet here you guys are still talking about 'the code'. wow
The whole thrust of my contribution here, was highlighting the safety of picking an adequate extension cord to match his load / breaker size. Using a needlessly larger breaker amperage or thin cheap extension cord is risky. full stop. A breaker isn't designed to protect any wiring beyond the outlet, so we need to apply a little common sense, and yet I was taken to task over and over by the code boys. good job!

 

[lakeroadster]

Infinia... you keep targeting people, ad nauseam, and your signature line is:

"Great Minds Discuss Ideas; Average Minds Discuss Events; Small Minds Discuss People"

I for one value the code guys input.

 

[Walter_TA]

And this thread is still open, and gets longer with more #$%$ in it. By the way @wyliesdiesels is the best. Good clear correct help.

 

[pattenp]

And this thread is still open, and gets longer with more #$%$ in it. By the way @wyliesdiesels is the best. Good clear correct help.

Don't go blowing up wilies head, it big enough already. And so is this thread.

 

[alfredeneuman]

Infinia:
"da code da code, for the third and final time what does this thread have to do with code?"
OP said in his first post:
"So...is it ok to run a dedicated 20 amp circuit for a 15 amp compressor? Or should I switch it back to a 15 amp breaker? Thanks."
To answer that requires some knowledge of the Code.

 

[wyliesdiesels]

And this thread is still open, and gets longer with more #$%$ in it. By the way @wyliesdiesels is the best. Good clear correct help.

Well thx but I dont consider myself the best.

There are several masters on here that are way more versed and skilled than me.

Don't go blowing up wilies head, it big enough already. And so is this thread.

Willie? Who's that? Was that a typo

And thx for the laugh. slick willie has a big head... ahahahahhahaha

 

[sberry]

A breaker isn't designed to protect any wiring beyond the outlet, so we need to apply a little common sense

But it is. Not against thermal but against short circuit. A cord wont overheat provided its heavy enough to serve the load, in this case 14, then the breaker needs to be limited to provide adequate fault protection up to any additional protection if it has it within the unit. In the case of 14 wire this would be 30A.
This is why we fundamentally,,,,,,,,, (this is why the listing is important,,,, its not always due to the fact that it may overheat the recept) but that the cord and the internals of the appliance are not rated for interruption on larger circuits.
This is why7 the 50 to 20 adapter isn't allowed. Not including the internals,,, but it allows things with a cord smaller than a number 12 (which a 240 v 180A mig has) to be connected to a 50A,,, in this case a compressor with a 14 cord could be plugged in to a 50A circuit.
I agree with some others here, its the code and for good reason and for reasons clearly illustrated in this thread. One doesn't need to have extensive knowledge of every aspect of circuit design, the installer simply follows the instructions. Its also obvious that we got lotso engineers not familiar with this, they may understand way more complex aspects of electrical theory but are sorely lacking in this aspect and it would be easy to cherry pick this thread for living proof of it.
Its also apparent one can get the engineering degree without ever opening the code book, this should be a course requirement, obviously not. (this does not apply to all engineers as a disclaimer) But it can be illustrated from cases where the simple statement that all 50A circuits require a 6 wire. If it was that simple then why he extensive education required. This was from someone that was a wireman before engineer,, wtf did we learn in the school? How in depth did they go in to simple fundamental circuits found in every installation in the country?

 

[Alchymist]

But it is. Not against thermal but against short circuit. A cord wont overheat provided its heavy enough to serve the load, in this case 14, then the breaker needs to be limited to provide adequate fault protection up to any additional protection if it has it within the unit. In the case of 14 wire this would be 30A.
This is why we fundamentally,,,,,,,,, (this is why the listing is important,,,, its not always due to the fact that it may overheat the recept) but that the cord and the internals of the appliance are not rated for interruption on larger circuits.
This is why7 the 50 to 20 adapter isn't allowed. Not including the internals,,, but it allows things with a cord smaller than a number 12 (which a 240 v 180A mig has) to be connected to a 50A,,, in this case a compressor with a 14 cord could be plugged in to a 50A circuit.
I agree with some others here, its the code and for good reason and for reasons clearly illustrated in this thread. One doesn't need to have extensive knowledge of every aspect of circuit design, the installer simply follows the instructions. Its also obvious that we got lotso engineers not familiar with this, they may understand way more complex aspects of electrical theory but are sorely lacking in this aspect and it would be easy to cherry pick this thread for living proof of it.
Its also apparent one can get the engineering degree without ever opening the code book, this should be a course requirement, obviously not. (this does not apply to all engineers as a disclaimer) But it can be illustrated from cases where the simple statement that all 50A circuits require a 6 wire. If it was that simple then why he extensive education required. This was from someone that was a wireman before engineer,, wtf did we learn in the school? How in depth did they go in to simple fundamental circuits found in every installation in the country?

^^^^

 

[J W]

I am an electrician, but have done a lot of automotive mechinacal work, I am very well rounded in many trades. But this thread is about electrical. I got here kinda by accident. I was Googling for some electrical info and saw that box where the Google nerds try to answer everything they are not qualified to answer. That statement is about everything, I see false information put out by Google on all sorts of things, automotive, solor power, medical things........... Anyway, I was curious as what they were saying about a 15 amp circuit and I was not surprised to see that they are full of **** once again, as they picked this thread out of this forum, a mechanical forum........ to form their opinion on. I read all of page one of this post, some of each of the others and did not see what I consider the correct answers on any of them, though some were workable. To directly answer his question first, about whether it is safe to plug that 15 amp compressor into a 20 amp circuit. The answer is an un-equivacal yes, it is very safe and is practically required. The compressor will pull what it needs, if it pulls too many amps for the breaker it will open which stops the electricity. The reason I highly recommend a larger than 15 amp circuit is that an electrical motor requires almost half again the power to get it going as it does in running. If anything else were on the circuit besides the motor it is highly likely it would trip the breaker because of the starting load. A 20 amp breaker gives the additional room to safely start the motor of the compressor. Now for a few other things which are argued about in this thread included from the senior members is that the circuit breaker is to protect the wire in the building from overheating and causing a fire, not to protect anything connected to it. That is correct. Another thing is it is safe to connect something that only requires 50 watts (half an amp) into a 20 amp circuit. Yes it is. It will only pull what is needed for the item. And I saw many different things with bad info on them. First, a wire does not have to be large in order to trip the breaker. I have accidently let a 14 gaute wire hit the buss bar in a circuit panel and trip a 200 amp breaker. And man what a loud noise as the wire exploded when it hit the buss bar.
The 14 gauge is rated for 15 amps of use in a residence, but actually carries a 20 amp rating capacity. This is downrated by code to 14 gauge wire can have no more than a 15 amp breaker. These are the only faults I will address, however I see many more. When I need mechanical advise I will not hesitate to come here. But this is not a good place for electrical questions other than for automotive ones. Good luck all of ya, and BEWARE OF THE ANSWERS IN THE GOOGLE ANSWER BOXES!

 

[sberry]

You will love this then. The breaker almost never protects wire after it for thermal other than on general use circuits with multiple recepts, it could but doesnt. Breakers protect wire ahead of it,,, service entrance,, the reset button on a power strip.
The common blanket statement we see shot out at near every thread is rather simplistic at best. The code does tend to assume all was done correctly and that someone didn't put the wrong end on a cord allowing it to be plugged in to a circuit with inadequate wire. The breaker would thermal protect in that case but with the correct plug on a circuit with single outlet the breaker only provides for short circuit.

 

[sberry]

I was considering if the breaker protected the travel trailer cord or circuit wire, that would be sort of,, at least the building wire to some extent but only slightly and the cord not really,, there is a legal 50/30 adapter for it, the thermal is really downstream similar to a power strip.

 

[sberry]

It's why the don't make 3 way for other circuits. You can put multiple recepts on a welder circuit and be safe as long as a undersized wire isn't used to daisey chained to connect them
. No 3 way allowed because it would conflict with 6.11.