What is the difference between compression lugs with ring lugs

Whether Compression Lugs or Ring Lugs , They both have ring tongues, then they are the same in that single regard, but only that. There is a big difference in the termination technology.

In a compression lug, you have a specific amount of pressure that is expressed on the connector and conductor, theoretically to form a solid mass without voids that could lead to corrosion and resistance. In the process, the die of the compression tool leaves a specific mark that is only impressed AFTER the proper amount of compression pressure is applied, giving an inspector a visual indication that the lug is applied correctly.

A crimp type ring lug just relies upon a simple indentation on the copper lug body to flatten out and make contact with the conductor. Much less accurate, no true indication that is was done correctly etc. etc. I can’t tell you how many crimp terminals I have found in troubleshooting where the installer forgot to strip the wire properly (or at all) and crimped onto the insulation. The ring tongue lug had the proper dent in it, but there was LITTLE OR ZERO connectivity. That could never happen with a compression lug. But the technology for compression lugs is way too expensive to apply to small conductors.

There is also a HUGE difference in pull-out strength. I think it’s been shown that if you try to pull a conductor out of a compression lug, the conductor itself will fail first, but on a crimp lug, they pull out relatively easily.