Dissimilar metals in a ground wire

Found a residential main panel (200-amp GE) that has a copper ground wire and an aluminum ground wire connected to the service box together under one connect ‘clamp’. They used flux, too, but I’m wondering if these two dissimilar metals will effect the two grounds. Cliff Mark, Texas

First question is

  • Was it flux or was it anti-ox paste?

Second question is

  • Does Aluminum conduct electricity any worse or better than copper?

Answering these two will probably allay your concerns.

Copper and aluminum should not be touching. Also the lug would need to be Rated for two conductors .