RossS
Member
- Location
- Research Triangle, NC USA
- Occupation
- Electrical engineer
thermal data during the process would have been interesting
Do push-in connections actually overheat?
- Thread starter RossS
- Start date
kwired
Electron manager
- Location
- NE Nebraska
Your picture is missing the contact surface on the bottom side, which in both types is much larger. Your image is just showing the means to put pressure on that other contact surface.Holy freggin' hell. Now I understand you all's posts. I did not take into consideration the way I wrapped the wire around the screw. My bad. The point was to show surface contact and I was trying to do it fast to get back to some other stuff. Opps. Bunch of jokers. LOL All good.
Dang it. It's too late to edit it above.
View attachment 2571439
kwired
Electron manager
- Location
- NE Nebraska
I think the WAGO's have a better spring than the push in connections of a switch or receptacle device has and are better connection than the switches/receptacles give you.
Bear in mind most the receptacles that have this feature are the lowest grade receptacles made, and we all know how well the contacts hold a cord cap within just a year or so if that receptacle is used often, the push in connectors are on the same assembly made of same metal as the plug contacts are.
kwired
Electron manager
- Location
- NE Nebraska
I did have an incident where a lever lock did not survive the fault current during a fault incident one time.
Don't know what the available fault current actually was but it was a pretty short run to the branch breaker and that panel was basically right next to the larger distribution panel so should been much higher there than if it were at some remote location in the plant. Drive rectifier was what failed and caused the fault.
kwired
Electron manager
- Location
- NE Nebraska
same here. Has gotten to where I just use these on nearly all light fixtures anymore.
kwired
Electron manager
- Location
- NE Nebraska
true, but so far I've had no more call backs maybe even less call backs than for failed twist on connections.
I trust wago style or push-in quick connects for any sort of small stranded to solid connection. I have never trusted wire nutting those, the fine strands on fixture wires don't hold up well to splicing.
Anything else I'm using linemans and a wire nut, where the wire nut is more for insulation as I've already fully spliced them prior to application.
Anything else I'm using linemans and a wire nut, where the wire nut is more for insulation as I've already fully spliced them prior to application.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
With "Push In" style ... sometimes when you remove the device, the wires will also pull out. Also, many times the installer(s) will uses the device as a junction and not "Pig Tail" them.
4x4dually
Senior Member
- Location
- Stillwater, OK
- Occupation
- Electrical Engineer/ Ex-Electrician
I negated the bottom contact surface on both images on purpose. They are both just flat pads so it should be approx the same for each instance.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
But the connection may depend entirely on this back surface with the screw or clip simply providing a holding/pressing force.
I believe the device style stab-in uses only two pinch points while the wire nut clamp style uses pressure against the conductor.
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4x4dually
Senior Member
- Location
- Stillwater, OK
- Occupation
- Electrical Engineer/ Ex-Electrician
Important to keep in mind here, I'm not debating the new lever lock Wago style. I have no issues with the levers, just the flipper-spring type. No way the metallurgy of a spring clamp can remotely compare to the clamping and holding force of a screw. Anyway, I'm no expert at anything, just adding to the conversation.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Plus heat weakens the springiness, which leads to more heat, and the effect snowballs over time.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
I am not talking about the lever style either.
Spring clamp designs have been successfully used for more than a few decades, in most plug-in breakers.
I remember, some 15 years ago, when I got my first Hoffman enclosure heater with push-in connections.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
True, but bus stabs have much more contact area than a cylindrical conductor.
4x4dually
Senior Member
- Location
- Stillwater, OK
- Occupation
- Electrical Engineer/ Ex-Electrician
Another valid point.
Having been a desk-jocky engineer for the last 27 years and counting, I haven't seen a lot of spring type connections since I'm not out in the field installing devices all day like you all are. We design DOD, flights, and ISS equipment and it's ring lugs and torqued screws all the way here so I can't speak to what all brands use them and the longevity. It just seems like a failure waiting to happen to me.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I remember old tandem QO breakers with push-in terminals.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
But the QO bus connection is made with a type of spring clamp. CH, tan handle, breakers also use a clamp that has what looks like a helper spring.
Almost every 1" wide residential breaker uses a spring design to connect to the bus.
Even all receptacles use spring clamps for their plug connections.
Many specifications are passed down from one generation to the next, so we do things the way grandpa did. There was a time when spring style twist on wire nuts were not allowed, specs often called for set-screw style wire nuts with separate twist on insulator caps.
My point, is do not lump all push-in connections into the same basket.
Some are better than others.
And of course if it works why change it?
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The fact that one method is superior does not necessarily mean that the other is not sufficient for the task at hand.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I thought I posted this but don't see it. There was a member here that ran a test using push-in connectors (Wago. Ideal) and regular wirenuts.
He pushed several volts and high current through both. Both connectors held up except the plastic melted like the video above. Both connectors' metal parts held intact up to a very high voltage. The wirenut may have held a little longer than the push-in connectors. However the current/voltage was way above what would be ran through them normally.
His conclusion, the push-in held adequately as well as the wirenut for their listed current/voltage range.
He pushed several volts and high current through both. Both connectors held up except the plastic melted like the video above. Both connectors' metal parts held intact up to a very high voltage. The wirenut may have held a little longer than the push-in connectors. However the current/voltage was way above what would be ran through them normally.
His conclusion, the push-in held adequately as well as the wirenut for their listed current/voltage range.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Each connection is designed for its purpose. It is totally possible to engineer clamps for limited wire sizes.
The breaker needs to exceed 100A, while a wire nut or control terminal may only need to handle 30A.
This is similar to the discussion of bolt-on versus plug-on breakers in panelboards.
Years of experience have shown properly terminated devices are not prone to failure.