In general, tin-plated copper compression lugs, installed on appropriate copper conductor and under normal conditions of use, are rated in the industry for use up to 300oF (149oC) actual operating temperature.
In typical applications with 75-90oC (167-194oF) rated wire systems, the lugs will normally experience a moderate temperature rise (due to self-heating because of their own resistance) when carrying normal rated amperage. With correct selection and sizing, proper installation (cleanliness, compression, bolt-down torque, etc.) and under normal usage conditions (amperage, ambient temperature, pad conductivity, cleanliness, etc.) the resulting operational lug temperature will remain well below the 300oF (149oC) capability of standard tin-plated copper compression lugs.
For operation above 300oF (149oC), nickel-plated copper lugs are suggested, which are rated up to 650oF (343oC).