What to do with wires when installing light switches/plugs

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JWelectric

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Having been in this trade for many years I have found that poor workmanship is the cause of many failures. I have seen the top end devices that had failures due to someone not tightening the screw down tight enough to hold the conductor in place. I have seen the conductor stripped out to much and the equipment grounding conductor fault out the device. I have seen the insulation not stripped out enough and have arcing between the conductor and the device to the point of failure.

What I have never seen in almost 50 years of experience is a stab-loc failure when installed per the instructions that come with the device and the device not overloaded.

My point being is that any installation that is not done in a good workmanship manner will fail no matter how much is spent on the device or what method is being used to terminate the conductor. If done properly the stab-loc is just as good as any other method. The wrapping of the screw is bad if not done properly.

A #14 conductor has a area of .0097 square inches. Wrapping the conductor around the screw does not give more area for the conductor to contact the dev ice as the maximum current carrying area is limited to the area of the conductor.
In other words as long as .0097 square inches of conductor is in contact with the device the maximum amount of current that the conductor can carry is flowing to that device and wrapping the conductor around the screw in no way allows more current to flow through the conductor
 

DonL

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I say 0.0032 sq inches. The radius of 14AWG is 0.03205

So (0.0032 in) x (0.0032 in) x (3.1416) is 0.0032 sq inches

Lets say math may not be your strongpoint.



LOL, are you allowed to say that ?
 

JWelectric

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I say 0.0032 sq inches. The radius of 14AWG is 0.03205

So (0.0032 in) x (0.0032 in) x (3.1416) is 0.0032 sq inches

Lets say math may not be your strongpoint.

Well let's see what the NEC has to say

I think maybe we both missed it
 

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Hammerlane

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Well let's see what the NEC has to say

I think maybe we both missed it

My figures were based on AWG solid conductor size, I believe the table you quoted refers to conductor and insulation.

ANd I do understand your point when you spoke about the contact area at the device regarding ampacity.
 

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JWelectric

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Using either table to get the area of the conductor and looking at the picture you posted of the receptacle with the stab-loc connection we can come to the conclusion that if the conductor is terminated using the proper method the area of contact with the receptacle is far more than the area of the conductor.

If the contact area of the conductor is more than the area of the conductor itself then the amount of current flow is not impeded in any way.

Then what causes the failures that everyone seems to be finding? It must be one of two different things. One the termination was done improperly or the device was overloaded. In either case it was not the fault of the method of termination but the misuse of the device.

What many find hard to believe is that even methods such as using an upturned lug or wrapping the conductor around the screw can fail if done improperly. How many devices have you found that the screw was not to the proper torque? This is common on the neutral terminals in panels. Ever see the white turning brown on these conductors?

Over the years of my experience I have learned that saying one method is inferior to another or that one electrician is inferior to another gets one nowhere but in the lime light of an ego trip. The truth of the matter is that the push-in method is just as reliable as any other method as long as the proper method is carried out when doing so and no matter how it is done the device is only rated for 12 amps. A case in point is using the device for a feed through connection. Personally this is not something I look at as being a good idea using either method of termination. I have always only connected three conductors to a receptacle, one black, one white, and one EGC. It is common practice to feed through the device but in the event of a repair then the entire circuit is opened but if only one conductor is terminated on the device one does not open the entire circuit doing a repair nor is the first device carrying the entire load of the circuit.

The one thing you will never hear come from my lips during a service call is that my method is any better than the person in front of me. What I do is spend that energy explaining to the homeowner that they need to get rid of that tender box they have plugged into the failed device. I take the time to explain that the device will only handle 1440 watts of continuous current flow and that continued current flow of more than this will cause the device to fail and end up costing them at the very least a service call but could end up costing them everything they own.
 

JWelectric

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What is the continuous current rating for a 20A duplex receptacle?
16 amps if on a 20 amp circuit
A 20 amp receptacle is not supposed to be installed on a 15 amp circuit but a 15 amp receptacle can be installed on a 20 amp circuit as long as there is two or more places where something can be plugged into the circuit.
 

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rosem637

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The back wired way has that tensioned piece of metal that holds pressure against the wire. This keeps the wire in place and from falling back out of the receptacle but it doesn't keep the wire from turning in the terminal hole. If it can turn it is not secure. The proper way to make connections is to use the side setscrews or brackets under them to tightly grip the wire to these devices. This is the way the professionals would do it and that should be a clue to which connection is the appropriate connection.
 

JWelectric

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The back wired way has that tensioned piece of metal that holds pressure against the wire.
And the amount of tension used to hold the conductor in place is the amount of pressure in foot pounds required for the conductor to be secured to the device.

This keeps the wire in place and from falling back out of the receptacle but it doesn't keep the wire from turning in the terminal hole.
Once the device is secured to the box I don’t see how the conductor can be turned in the hole. Could you take a few minutes to explain just who is doing this turning of the conductor after the receptacle is secured to the box.

If it can turn it is not secure.
I suppose if we take the receptacle back out of the box on a daily basis and use a pipe wrench to turn this conductor there might be something to this statement but if no one is taking the device back out of the box turning the conductor then just what are you talking about.

The proper way to make connections is to use the side setscrews or brackets under them to tightly grip the wire to these devices.
The Standard to which the receptacle is manufactured disagrees with this statement. Are you on the UL Standards committee? If not this I would say this is nothing more than opinion.
This is the way the professionals would do it and that should be a clue to which connection is the appropriate connection.
With all those professionals doing it this way does this mean that all those posting of the failures they are finding is nothing more than a lie.

A true professional will install anything according to the instructions included in the listing and labeling of the equipment as outlined in NEC Section 110.3(B). The instructions that is included in the listing and labeling of the devices in question in this thread say to strip the conductor to the strip gauge on the device and insert it into the hole in the back of the device.

Of course there are many DIYers that think they are far superior in knowledge than those who design the equipment they want to use and have found many different methods of making installations that exceed the standards by which the equipment is manufactured.

The bottom line is that one method when done properly is no better than another. Anyone who says different is doing nothing more than expressing their opinion as these devices are tested every day of the week for the method listed. If there was a safety issue with the method then UL would not list it as a method of terminating a conductor to the device.
 

DonL

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Once they are mounted it the box they will not move.

But they may turn a bit while installing, but that should not be a problem.

Most of the install errors that I have seen, Is the nicking of the conductor when removing the insulation, and that is a No No.


Have Fun.
 

rosem637

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Seeing is believing. Side wired you can see. Back wired you cannot. Stop drinking the kool-aid. Side wired is more secure.

This is my point only. Side wired is more secured. I can deviate back-wired connection with about 45 lbs of force. With the same forc the side wired connection is unscathed.

Test is proof positive.
 

JWelectric

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Brother Don you have hit the nail on the head with most problems found in residential wiring or at least let me say that it has been my experience.

Young journeyman stripping conductors twist the strippers to and fro breaking the insulation free, opps the damage is done but they don’t trim it off and start over they just continue on without a care in this world.
Grab the conductor in the wrong hole of the strippers and then move to the correct hole, sorry damage is already done to the conductor.
One of my most favorite is the fellow grabbing two conductors at one time with dime store strippers that are not designed for the purpose.

Taking a phrase from some who are against the stab-loc, “if I had a nickel for every time,†I have found a handful of white conductors joined with a wire nut and one or two in the middle would be broke completely free “I would be a millionaire.†This comes from ringing the conductor with the strippers and also causes the burning of the stab-loc connection. We like to bend the end so when we do damage the conductor it breaks off and tells us we goofed.

When having lab with one of the classes I watch for this and try to head this habit off before it ever gets started by holding the stripped part of the conductor in my lineman’s pliers and with a couple of bends it breaks clean.

People do it and aren’t aware that they are damaging the conductor. No concentration at all, to busy jumping around to the beat of that awful mess coming out of that radio blasting louder than the jack hammer in the background.
Geez what is this world coming to? Next thing you know they will be demanding a water cooler and a chance to run to the port-a-jon every 30 minutes. That ain’t the half of it, they will be wanting to get paid to drink that water so they will have a reason to run back and forth on payroll.
 

JWelectric

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Seeing is believing.
Ever been to a magic show? I suppose you believe everything you saw, I know that some do. Poor folks will believe about anything they see and all they are told.

Side wired you can see.
So this proves what? Does being able to see something somehow make it better or is it something personal.
Back wired you cannot.
Are you blind or something? Are you working in the dark? How are you seeing the “side wired†but not able to see the back wired?
Stop drinking the kool-aid.
I already did way back years ago. I drink no less than 64 ounces of water a day now. It is better for you. Try it and see if things aren’t better.
Side wired is more secure.
And this means what? Ever see an earthquake? Sometimes being more secure means more damage. As a child I liked being close to mommy as this made me feel more secure.

This is my point only. Side wired is more secured. I can deviate back-wired connection with about 45 lbs of force. With the same forc the side wired connection is unscathed.
Just how much force do you think it takes for current to flow. Ever hear of the UL White Book? Why do you think it needs 45 foot pounds of torque to hold the conductor?
As to deviating, I suppose that anyone could deviate from anything if they try hard enough. For the wire binding screw of a device one could deviate in many different ways such as but not limited to turning the conductor counter clock wise around the screw, stripping to much conductor, stripping not enough conductor, damaging the conductor during the stripping process, not tightening the screw enough, or even trying to secure the conductor to the screw by exerting 45 pounds of torque and stripping the threads of the screw.

So just what is you point again?

Test is proof positive.
What test? All I have seen here is opinion that if you can see it then it must be better. This is not a test. A test is where you load the connection to the maximum amount of current for a predetermined amount to time not standing back looking at what you have done with no current.

Not wanting to be rude but the only proof positive I can find in this post is that you are very unsure of your comments and know little about the amperage rating of the device you are installing. You seem to be saying that by using the wire binding screw somehow makes the device rated for more current or that the securing of the conductor by the screw where it takes 45 or more pounds to remove the conductor that somehow this makes the device better.

Get a spec sheet form Leviton and you will see that the required torque for tightening of the screws is 14 ft. lbs. and would you like to guess what the foot pounds of the stab-loc of the same Leviton receptacle is?

Seeing is not always believing. I can make a quarter disappear right before your eyes but it did not disappear it was sly of hand and you believe you saw the quarter disappear. Education is where believing comes from. Seeing all the complied data from the testing labs is where seeing is believing comes from not from looking at something.

A very simple question we can ask ourselves to ascertain the information concerning this topic is, if it were no good then why do they continue to manufacture the devices with stab-loc. The simple fact that the devices are continually being manufactured with stab-loc says something to those willing to learn.

But if your mentality is, I know more than those who design and test these devices then there will be no future education as you already believe you are smarter than those who made the device you are installing.

The device in question is rated for 12 amps. Using the wire binding screw and tightening the screw to just before stripping the threads and the device is still rated for 12 amps. Failure of the device starts anywhere above 12 amps no matter the method used to terminate the conductor.
We can install #12 cable and terminate using the screw but the device is still rated at 12 amps. Nothing we do will change the fact that the device is rated at 12 amps but there are many who believe that using #12 conductors and terminating using the screw someway makes it a better installation when the fact remains that the device is rated at 12 amps. These are the facts weather you believe them or not. Believe it or not but the receptacle is still rated for 12 amps.
 

Wet_Boots

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As a side note, I suppose the 'area of contact' idea allows for side-wiring without looping the wire around the screw.
 
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