Burning smell and burnt wire at SSR terminal

I've been running my EHERMS system for over a year now with no problems. The other day I smelled a burning plastic smell and noticed one wire on my SSR was burnt at the terminal. The wire is not in contact with anything else and the plastic cap is on the SSR. Does this simply mean I have a failing SSR? It still works but after about 10mins of use I smell that smell again. The wire that is burnt is one leg of a 220v that powers my HLT element. If I run the element in manual mode bypassing the SSR it works as it should.

It sounds like you use crimp on connectors for the wire to SSR terminal connection.

If that is the case, that is the reason for the failure. Most of the common crimp tools do a very poor job of crimping. The connection needs to be soldered as well to prevent failure.

Or buy a better crimp tool.

IMHO

It could be a hi-resistance joint causing excessive heating. That may be a bad / loose crimp if you're using that type of terminal end or an oxidized connection at the SSR screw. I'm not sure if localized heating at the terminal would shorten the life of the SSR. I would say remake the high voltage connections so everything is clean & tight and see what happens and if the heat on the heat sink side seems normal.

yep, what P-J said - he beat me to it!