|
|
|
Question about Outlets and terminals/push-in(real question, not a troll)
Is it allowable to use BOTH screw and push-in's on the same receptical?
My situation is this, I have 3x 14/2 romex running into a 12.5ci (2"x3"x2.5") box.
the Ontario electrical code allows 6 conductors and 0 or 1 marret in that size of box.
If I can use both screw terminals and 1 push in I would need no marrets, but if I can't I will have to try and find a 2x3x3 box.
I personally use marrets and pigtails normally when connecting outlets, but because this box is a little small it has raised this issue
There are receptacles that have rear contacts that rely on a screw to clamp it in place. Those are fine for your application. I've never liked the ones that relied on spring pressure to hold it in place. Otherwise, maybe a bigger box is the safer way to go.
Jim DeBruycker
Important note - I'm not a pro
Retired Defense Industry Engineer
UL has tested the push-in connections on the back of receptacles and switches at their rated load and has approved them for this use.
Should anyone come along and try to sell you the idea that the push-in connections are bad then they are trying to say that they are smarter than UL.
What your propose is just fine and legal
jw..........what you say is of course completely accurate. But in the same vein, there are plumbers who use plumbqwik one piece stop/riser combos, and push on valve/riser combos....because they are UPC/IAPMO listed, and they speed up new construction. Some of the plumbers on the forum would never use such products, because experience tells us that these products do not have the same long term reliability as better ( slower install types) products do. It is just a personal choice. Which product to use can also of course be a stricly business decision.
I am sure you have read or even posted on question from consumers trying to find why some of their outlets and switches do not work...and the answer often is a faulty push in connection. So you are correct....but those who might recommend sturdier products are also correct.....n'est pas? as Frenchy the electrician would say!
You are correct Jim in so much as ignorance builds a fear that can’t be explained away.
From 1979 through 1987 about 98 percent of the work I did was apartment townhouses and condominiums. For this nine year period I carried the maintenance contract on all but two of these projects. The smallest project was 125 units with most being between 225 and 250 units. Each unit would have between 40 to 50 devices (switches and receptacles) that were installed using the stab-loc connection included with the device.
Over this nine year period of installations I would estimate somewhere around 10 thousand units were wired with somewhere around three to four hundred thousand devices wired.
Now I must ask if this stab-loc was so bad why I didn’t experience a massive failure back when the twenty amp circuits were included in the stab-loc.
On the few failures (less than 50)and we almost always found portable electric heating equipment in use on the failed device. In the years of carrying the maintenance contract on these units not one switch failed. I am of the opinion that when there is a .0001 percent failure rate that the failure rate is nonexistent.
What I have come to the conclusion of concerning the stab-loc connection is that all failures are the direct result of either misuse (overload) or improper installation.
When these devices are properly installed and the circuit is not overloaded these type installations are just as safe and efficient as one wrapped around the screw. It has also been my experience that when the screw was used and the device overloaded the device would get to where the cord would not stay in the receptacle which is a blade being stabbed into the tension of the receptacle. Is this not the same principle as the stab-loc? So to say that the holes in the back of receptacles are bad, would not the holes in the front of the receptacle not be just as bad?????????
As to the plumbing I have no answer as I do no plumbing or do I do research as deeply as I have the stab-loc devices.
Hardly any organization ever admits they screwed up. You should have seen the gyrations the Patent Office went through when they failed to find a previous valid patent and so granted a new patent for the same invention.Originally Posted by jwelectric
The customer is the ultimate testing lab and only statistically significant [hypothesis testing, double-blind studies, etc.] results count.
Last edited by Thatguy; 11-06-2010 at 09:19 AM.
The plug on a cord has MUCH more surface area, and spot heating and resistance is less on heavy loads. The prongs on a back-stabbed device have much less surface area (but higher pressure). Given a choice, I'd prefer a device with a larger contact area, and that means a screw or a screw and clamp. Especially in a feed-through situation, I prefer a better connection than those small spring prongs.
Jim DeBruycker
Important note - I'm not a pro
Retired Defense Industry Engineer
I had a friend call yesterday, who has three outlets in the master bedroom which do not work while the other three do. After talking to him, it appears that the only source of the problem must be where those three attach to the other three. AND, since the wiring is done with "back stabbing", the inference is that one of them must be faulty. I also told him to plug a lamp into the bad outlets, because the simple process of removing the receptacle from the wall, COULD move the bad connection sufficiently to reenergize it. If that were to occur and he did not have a lamp which would illuminate when it happened, he would still not know where the problem was when he went back and retested the outlets and they were then working.
And just pushing on and releasing the outlets while the lamp is plugged in may reveal the bad outlet.
Has Mike Holt taken an official position on back-stabbed outlets? He seems to come close with AFCIs.
Last edited by Thatguy; 11-06-2010 at 02:33 PM.
You do not need Einstein to see that the tiny surface contact area of a stab in device is a problem waiting to happen. If pulled back hard when inserted and twisted a bit, it might be good forever. On high amp draws they likely arc until they melt together at which time they become "safer"
Back stab with a SCREW on the side seems to be the way these days except on the cheapest outlets.
But I have used them years ago and always felt a bit regretful. I have had call backs for bad connections. Often a whack or touch or twist will reconnect them. Sounds like TROUBLE to me.
Never more!
Thatguy said a lot yesterday in two short paragraphs. Every post here has said pretty much the same thing. Thanks to the wisdom of crowds, I now vote against the jwelectric point of view. I might receive a failing mark if I were forced to take his course. It is true that ignorance "breeds" a fear.
Yes I agree that with the CPSC, NFPA, and all the other NRTLs throughout America that should UL miss something that all these other testing labs and the Consumer Protect Protection Agency would just sit in silence and let the public be at risk.
The area of contact of a stab-loc device is the area that is required for the 15 amp device to safely carry 12 amps which is the most that is allowed to be carried by any device installed on a 15 amp circuit installed in any manner in which it can be installed.
Should more amperage be allowed on this circuit there will be a failure somewhere on the device carrying the current which is a DIRECT VIOLATION OF BOTH THE NEC AND THE LISTING OF THE PRODUCT.
Every time this question is posted someone comes along with a friend that had one fail yesterday and cost millions of dollars in property damage and lost time. What no one has ever posted was what caused the failure. Without a doubt it is because one of two reasons, 1- improper installation, 2- overload. Which was the case with your friend?
Take a look at 210.21(B)(2) of the NEC to see that a high amp draw is in violation.
A prime case of the blind leading the blind and the blind is blindly following;
My friend it is not the view of JW Electric but instead it is the view of
Underwriters Laboratories
Met Laboratories
Intertek Group
National Technical Systems, Inc.
Wyle Laboratories
Nemko
National Electrical Manufacturers Association
Just to mention a few and then we also have the Consumer Protect Protection Agency which orders a recall when a product is dangerous and causes all this damage that these uninformed people keep preaching about simply to make everyone think they know something that their jaw is proving they know nothing or little about.
So my friend it is not something that JW Electric is saying but the greatest electrical minds in the country and those minds who are charged with our safety are saying.
It is not me that those who think that the stab-loc is bad is arguing with but instead it is those who are charged with listing and labeling the product they are arguing with.
It is not me that they are turning up their noses at but those charged with mine and your safety they are looking down at.
Now the choice is yours. You can believe those who post of forums such as this one or you can believe those who spend millions of dollars each year testing the products we use everyday.
I would suggest that if you are going to take the word of the individuals who post on these forums that you take action to destroy all those fools who put their labels on the products saying they are safe to use.
I found out about this "possibility" the hard way
http://en.wikipedia.org/wiki/Regulatory_capture
The newspaper code words for Capture are ". . .this agency is too cozy with the industry it regulates."
The agency I tried to blow the whistle on has been in the papers twice since 2002. It turns out that 600 to 6000 preventable fatalities in the US each year is "down in the noise."
In another flap at another agency I read that one guy actually said that "not enough people have died yet. "
I thank him for his honesty and hope I see him someday in a very hot place presided over by a guy with horns, a tail and a pitchfork.
The good news is, the thousands I spent for a lawyer in a vain attempt to keep my job were tax deductible. Wow!
http://www.imdb.com/title/tt0078966/
Last edited by Thatguy; 11-07-2010 at 07:45 AM.
Originally Posted by ballvalve
You do not need Einstein to see that the tiny surface contact area of a stab in device is a problem waiting to happen. If pulled back hard when inserted and twisted a bit, it might be good forever. On high amp draws they likely arc until they melt together at which time they become "safer"
From jwelectric: Take a look at 210.21(B)(2) of the NEC to see that a high amp draw is in violation
NEC= Numb-nuts excreting crap. "high amp draw is a violation?" Huh?
What on earth does violation have to do with everyday reality?
Tell it to your kid that stuck his fire truck ladder in the outlet, or mom that plugged in the 1800 watt heater to the 15 amp circuit that actually drew 2200 watts because of Chinese sabotage, along with the American dope that used a 20 amp breaker on the line.
Hey! its okay to design and install 12 million devices that will arc and spark rather than blow a breaker because if they do its a "violation".
JW posted:Please cite the source of these statements, especially "...12 amps which is the most that is allowed to be carried by any device installed on a 15 amp circuit..." It seems to me that you are confusing the requirement that continuous loads may only be a maximum of 80% of the circuit rating with the non-continuous rating of a device. To my knowledge there is NO limiting factor of 80% that must be applied to all devices in any and all service conditions.The area of contact of a stab-loc device is the area that is required for the 15 amp device to safely carry 12 amps which is the most that is allowed to be carried by any device installed on a 15 amp circuit installed in any manner in which it can be installed.
Should more amperage be allowed on this circuit there will be a failure somewhere on the device carrying the current which is a DIRECT VIOLATION OF BOTH THE NEC AND THE LISTING OF THE PRODUCT.
Or to put it another way, any device rated at 15 amperes should be able to carry that 15 amperes for a period of up to, but not more than, three hours of continuous operation without failure.
Posting Permissions
Reply With Quote
Bookmarks