Backstabbing Receptacles

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jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
I'm inclined to agree that pigtailing EGCs has more to do with paranoia than reality.

Backstabbing gets a bad rap because it can be done poorly in a number of ways and often is. One of the problems is that it's not a good thing to do in a box that's not very deep because the wires get shoved up against the back of the box and can be moved around when the devices put in place. I've also seen people try and use it with stranded wire which is just a terrible idea or with conductors that have not been stripped to the proper length. What you are calling the back stab is just a terminal that is spring loaded. Spring loaded terminals have been around for a long time and by and large they are as safe as screw-in terminals if handled properly. Personally I don't like wrapping stranded wires around a screw and then tightening the screw down. There's plenty of potential for messing that up too.
You probably haven’t done much service work. Backstabbing is one of the main causes of trouble I have seen. It gets a bad rap because it is a sloppy wiring method.
Wrapping stranded conductors on a screw is not good either. I don’t have my book handy but I am see code disallows it. Some devices are made to take stranded wire in a clamp. You can pigtail a solid wire in or use fork terminals. I don’t really like that but use forks if I have to.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I have never seen it done except where Romex is used. It seems likely to me it is because the installer is too lazy to coil the wires in an orderly manner and put them inside the outlet box instead of just jamming them in. With Romex there is a tail of bare wire that can go just about anywhere when care is not taken when the outlet is shoved into the box.

I'd guess where romex is involved its a HO. DIY books often indicate wrapping everything in electrical tape.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
I've seen a lot of back stab that had browned conductor or partially melted ones. Can't say I've seen a screw connection that was properly done and not overloaded show wire melted.
 
I have a couple burned up receptacles in my collection and neither were backstabbed. Just cheap receptacles.
Yeah, I think in general receps should have to be of higher quality. Based on the number I have seen fried from having electric heaters plugged in, they apparently frequently cannot handle the amperage they are supposed to be rated for.
 

kwired

Electron manager
Location
NE Nebraska
I am not a fan of backstab receps. That said, I see it has a product standard issue not an NEC issue. An 800 amp I-line breaker has a spring tension connection to the bus. I think receptacle backstabs need to be of a better and higher quality design.
I'm not either. Consider the fact they generally only available on the low grade devices. When it comes to receptacles those are the ones that won't hold a plug very well after a year or two of regular use either. I'm somewhat insistent on only using spec grade receptacles for that reason in dwellings. At very least in kitchens, laundry, bath, garages, or any place you know will get heavy usage. I can't recall spec grade (other than some decora line types) that have push in rear entry, insert from rear and then tighten down a pressure plate they do have.
 

kwired

Electron manager
Location
NE Nebraska
You probably haven’t done much service work. Backstabbing is one of the main causes of trouble I have seen. It gets a bad rap because it is a sloppy wiring method.
Wrapping stranded conductors on a screw is not good either. I don’t have my book handy but I am see code disallows it. Some devices are made to take stranded wire in a clamp. You can pigtail a solid wire in or use fork terminals. I don’t really like that but use forks if I have to.
Wrapping stranded conductors around screws has been discussed here before. Code doesn't say anything, I believe listing standards is what allows it.

I have used stranded quite often, can't ever recall being called back for one failing, or seen others that did without also seeing other questionable install practices to go with it. What I see the most failures of regarding stranded conductors is those "quick disconnect" terminals failing. I think they are fine for low current controls and such, but keep them away from higher current applications.
 
D

Dell3c

Guest
You probably haven’t done much service work. Backstabbing is one of the main causes of trouble I have seen. It gets a bad rap because it is a sloppy wiring method.
Wrapping stranded conductors on a screw is not good either. I don’t have my book handy but I am see code disallows it. Some devices are made to take stranded wire in a clamp. You can pigtail a solid wire in or use fork terminals. I don’t really like that but use forks if I have to.
.. Brother from hometown of "Bull City".. In reading your post, happen to have NFPA 70 book open.. Let's see if can assist you w/ what your looking. Chapter 1/ Article 110/ Section 14(A)..
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
I'm not either. Consider the fact they generally only available on the low grade devices. When it comes to receptacles those are the ones that won't hold a plug very well after a year or two of regular use either. I'm somewhat insistent on only using spec grade receptacles for that reason in dwellings. At very least in kitchens, laundry, bath, garages, or any place you know will get heavy usage. I can't recall spec grade (other than some decora line types) that have push in rear entry, insert from rear and then tighten down a pressure plate they do have.
Those that stab snd screw down are the best IMHO. They are good for stranded wire also.
 

paulengr

Senior Member
You probably haven’t done much service work. Backstabbing is one of the main causes of trouble I have seen. It gets a bad rap because it is a sloppy wiring method.
Wrapping stranded conductors on a screw is not good either. I don’t have my book handy but I am see code disallows it. Some devices are made to take stranded wire in a clamp. You can pigtail a solid wire in or use fork terminals. I don’t really like that but use forks if I have to.

A spring clamp terminal has been proven to hold better than a screw terminal. In vibration or heating/cooling it does better.


They are definitely UL Listed.

That being said the typical DIN rail terminals require you to insert a 1/16” flat blade screw driver to open the haw, insert the wire (stranded or solid), then pull the screwdriver out. Push ins work similar except they only work with solid and the wire itself does the job of the screwdriver. But if the wire is not straight or inserted fully you will have problems. Then again I’ve had plenty of problems if I don’t insert a wire fully into ANY terminal. One of the tricks of the trade is to ALWAYS give the wire a good hard pull after landing it. This simple step would probably catch all your failures because the damaged ones I’ve found pull right out. So is this the fault of the manufacturer (UL testing) or the installer? Hint: workmanship might have something to do with it even if UL doesn’t.

I’ve seen burned wire, LOTS of burned wire. I’m a service engineer for a motor shop. We see failures almost every day. If a termination is done improperly you get brown discolored wire nut also if the circuit is overloaded repeatedly over the years the same thing happens. Resistance is always higher at joints so it is the first area where you see issues even with good solid connections.

I’ve had ZERO problems with stranded wire with a couple exceptions. Fine stranded wire takes a fine stranded terminal. Aluminum set screw type mechanical terminals have a tendency towards galling badly which is the beginning stages of stripped out (it already is) but can fool you into thinking it’s right when it’s not. Polaris tap type insulated terminal blocks fail a lot in motor peckerheads. Both stranded and solid wire in wire nuts in high vibration is a recipe for trouble. But if stranded wire was so horrendous then all the equipment that comes with pigtails such as NEMA style motors would have used solid core years ago, in fact it is rare in commercial/industrial and often the sign of an amateur. Granted the opposite is true in residential.
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
A spring clamp terminal has been proven to hold better than a screw terminal. In vibration or heating/cooling it does better.


They are definitely UL Listed.

That being said the typical DIN rail terminals require you to insert a 1/16” flat blade screw driver to open the haw, insert the wire (stranded or solid), then pull the screwdriver out. Push ins work similar except they only work with solid and the wire itself does the job of the screwdriver. But if the wire is not straight or inserted fully you will have problems. Then again I’ve had plenty of problems if I don’t insert a wire fully into ANY terminal. One of the tricks of the trade is to ALWAYS give the wire a good hard pull after landing it. This simple step would probably catch all your failures because the damaged ones I’ve found pull right out. So is this the fault of the manufacturer (UL testing) or the installer? Hint: workmanship might have something to do with it even if UL doesn’t.

I’ve seen burned wire, LOTS of burned wire. I’m a service engineer for a motor shop. We see failures almost every day. If a termination is done improperly you get brown discolored wire nut also if the circuit is overloaded repeatedly over the years the same thing happens. Resistance is always higher at joints so it is the first area where you see issues even with good solid connections.

I’ve had ZERO problems with stranded wire with a couple exceptions. Fine stranded wire takes a fine stranded terminal. Aluminum set screw type mechanical terminals have a tendency towards galling badly which is the beginning stages of stripped out (it already is) but can fool you into thinking it’s right when it’s not. Polaris tap type insulated terminal blocks fail a lot in motor peckerheads. Both stranded and solid wire in wire nuts in high vibration is a recipe for trouble. But if stranded wire was so horrendous then all the equipment that comes with pigtails such as NEMA style motors would have used solid core years ago, in fact it is rare in commercial/industrial and often the sign of an amateur. Granted the opposite is true in residential.
I have to disagree on stabbing. I’ve seen too many problems. True, not every stab gives trouble but many of the issues I’ve seen were with stabs, from the late 1970’s to today. I’ve seen a lot fewer problems with screw terminals or clamps. I like stranded wire, it pulls easier & packs better into a box. A bit harder to terminate without a clamp device. Agreed on splices, they need to be done well. I prefer 4 wires max, 3 is better. As far as UL, their emblem is nothing more than a costly trademark. I have seen a lot of junk with their labels.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
Push ins work similar .... But if the wire is not straight or inserted fully you will have problems.
I've made the same assertion many times. Not only receptacles, but WAGOs, too.

Wires that are kinked, curved, etc just will not make a good enough contact. But that's not an issue with the device, it's installer error.

It's no different from somebody wrapping a wire around a screw backward, it gets pushed out as the screw is tightened, has a horrible connection as a result, burns up, then somebody badmouths the screw. 🙄
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
I've made the same assertion many times. Not only receptacles, but WAGOs, too.

Wires that are kinked, curved, etc just will not make a good enough contact. But that's not an issue with the device, it's installer error.

It's no different from somebody wrapping a wire around a screw backward, it gets pushed out as the screw is tightened, has a horrible connection as a result, burns up, then somebody badmouths the screw. 🙄
Agreed on the screws. I’ve scolded a lot of helpers that refused to get that right.
BTW, I just recalled seeing stranded wire leads on some piece of equipment years ago that had soldered ends, still flexible enough to wrap a acres terminal. Only saw them that one time.
 
D

Dell3c

Guest
I've bought eight or nine different books lately. The Handbook wasn't among them, but it sure was tempting..
 
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