Do push-in connections actually overheat?

[ptonsparky]

By the looks of the video posted even the knockoffs were adequate for normal operations.

 

[a.bisnath]

All connections are to be mechanically and electrically sound .One consideration is whether solid or twisted stranded wire is being used. I would never use stab or spring type for power connections ,I have seen them fail and burn receptacles. they can work fine for controls and instrumentation applications like control and pilot relay circuits, 4 to 20 mA transmitters, etc - generally low power usage. Surface area contact and tightness are essential to prevent oxidation and heating at connection points. Its even more bad if its aluminium wires being used.

 

[kwired]

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.

But that opposite pad is what is the primary current handling device of the connection and not so much the underside of the screw head or the tip of the spring. In a WAGO that spring might be tempered steel (which is going to give better spring pressure than what is in switches/receptacles and that flat pad is something of higher conductivity and is intended to handle the current carrying functions.

 

[kwired]

Plus heat weakens the springiness, which leads to more heat, and the effect snowballs over time.

heat weakens the contact pressure in any connection type. It may start out rather unnoticeable but every time the connection heats up the resistance increases a little more until it gets to a point where the heat is rather extreme over a small area. that iswhat eventually leads to glowing connections.

 

[zbang]

How does that work for what should be a copper-to-copper gas-tight connection?

 

[RossS]

Another factor to consider is also if the wire connection is listed then it faced destructive testing. Wago and Ideal products are fairly respected even with their push ins when in the past installer error and other issues causes some concern for some people

I assumed that was the case (the destructive testing). But I was eventually able to talk to a technical representative at WAGO who informed me it's definitely not the case. As he told me, UL is a performance standard, and in order to be listed, a manufacturer only has to certify that their product meets those standards. There is no test-to-failure requirement, and apparently even no requirement that the testing be conducted by a NRTL. WAGO's testing results are proprietary, which is understandable, but they did share with me the relevant testing protocols, and the pass/fail thresholds are pretty robust.

 

[kwired]

I assumed that was the case (the destructive testing). But I was eventually able to talk to a technical representative at WAGO who informed me it's definitely not the case. As he told me, UL is a performance standard, and in order to be listed, a manufacturer only has to certify that their product meets those standards. There is no test-to-failure requirement, and apparently even no requirement that the testing be conducted by a NRTL. WAGO's testing results are proprietary, which is understandable, but they did share with me the relevant testing protocols, and the pass/fail thresholds are pretty robust.

NRTL's wouldn't necessarily test items to a failure point but manufacturers very well might in their own R&D labs. They also could test things to assure they meet a standard that is a higher standard than listing standard may be, if they want their item to meet that higher standard.

 

[letgomywago]

Just remember everyone wire connectors aren't required to be listed still just throwing this out there. They only need to be identified

 

[RossS]

NRTL's wouldn't necessarily test items to a failure point but manufacturers very well might in their own R&D labs. They also could test things to assure they meet a standard that is a higher standard than listing standard may be, if they want their item to meet that higher standard.

That's what WAGO provided me; their testing standards which meet or exceed UL standards.