Well, at least it is silicone rubber jacketed wire... I always wondered if china rated a wires ampacity as the point at which the wire melted open like a fuse.

Like the "fusible link" in a car, two sizes unded the gauge of the wire it's meant to protect, but short in length and silicone insulated. The wire melts but the jacket doesn't.

 

I have noticed that electrical wire is now rated to higher currents for a given size because the insulation is rated higher, i.e. 125 degrees Celsius. The wire will get hotter but the insulation with a higher rating will not melt with the extra heat causing a fire in a house. The connector may skimp by but the wire used may catch fire. So beware. I'm still trying to figure out how an IRFZ44N MOSFET can handle 50 amps through a TO220 case and legs. They sure are not 12 Gage leads

 

At one job I inherited a disaster of a project that included AMP brand connectors running at their published max ratings.
WHAT IS NEVER EXPLAINED IS THE VOLTAGE DROPS.
I did not look at the connector in question, but even if it can handle a few milliseconds pulse at that current the voltage drop would be unacceptable. It appears that many connector current ratings are based on pulses so short that nothing melts or even heats up. Unfortunately most real world applications demand that the device must carry current constantly.
The 20 amp rating for #12 wire is based on temperature rise , not fusing failure, which is when the wire melts and the circuit opens. That rating is much greater but not very useful. Of course, temperature rise is driven by the voltage drop, and so if your application requires some specific voltage then you must consider the voltage drop.

 

I have noticed that electrical wire is now rated to higher currents for a given size because the isolation is rated higher, i.e. 125 degrees Celsius. The wire will get hotter but the insulation with a higher rating will not melt with the extra heat causing a fire in a house. The connector may skimp by but the wire used may catch fire. So beware. I'm still trying to figure out how an IRFZ44N MOSFET can handle 50 amps through a TO220 case and legs. They sure are not 12 Gage leads

That 50 amp rating is under some very specific conditions that do not relate to real world applications, and also very narrow pulse widths that do not have time for any temperature rise. So if your application needs that 50 amp pulse for one NANOSECOND it may work OK, maybe, if that pulse is only every few minutes.

 

I guess my humor was lost there.
It's sad that we can't trust the datasheets verbatim. Getting to be like the politicians; can't believe a word they say. I am disappointed in the post about the comparing of the IRFZ44N, the FQP30N06L and the IRL3205 at a gate voltage of 3.3 volts.

https://forum.allaboutcircuits.com/...logic-level-irlz44n-irf3205-fqp30n06l.168699/

This poster said, "At a gate voltage of 3.3V, again the IRLZ44N performed best. Remarkably, the "logic level" FQP30N06L now performed worse than the IRF3205. A second FQP30N06L was tested but gave the same results."

This was certainly not what I experienced. I had definite failures with the IRFZ44N with 3.3 volt logic levels with my clock project. I also had definite success with the FQP30N06L at the 3.3 volt logic level. The results of the TS was no where near the data sheet specifications either. Something as small as a letter "L" in the nomenclature [of the FQP30N06L for instance] can change the whole specification, meaning a different datasheet.

 

I guess my humor was lost there.
It's sad that we can't trust the datasheets verbatim. Getting to be like the politicians; can't believe a word they say. I am disappointed in the post about the comparing of the IRFZ44N, the FQP30N06L and the IRL3205 at a gate voltage of 3.3 volts.

https://forum.allaboutcircuits.com/...logic-level-irlz44n-irf3205-fqp30n06l.168699/

This poster said, "At a gate voltage of 3.3V, again the IRLZ44N performed best. Remarkably, the "logic level" FQP30N06L now performed worse than the IRF3205. A second FQP30N06L was tested but gave the same results."

This was certainly not what I experienced. I had definite failures with the IRFZ44N with 3.3 volt logic levels with my clock project. I also had definite success with the FQP30N06L at the 3.3 volt logic level. The results of the TS was no where near the data sheet specifications either. Something as small as a letter "L" in the nomenclature [of the FQP30N06L for instance] can change the whole specification, meaning a different datasheet.

Sorry about missing the humor part. "Specsmanship" is an art practiced by those who want to stretch the truth very thin. That is why sometimes you see published the Test Circuit that was used to obtain some of those specs. And that is why I mentione the "Very Specific Conditions". For some devices that may be a huge water cooled heat sink, like ten pounds of copper that can absorb huge amounts of heat without getting very warm.

 

My bad. I misread the MOSFET IRLZ44N. in the previous post as an IRFZ44N. Seems the IRLZ44N has a gate voltage threshold of 1 volt, not the 2 to 4 volt I was thinking. Sorry for the mistake and confusion. . Joe