Speaker/Wire/Setup/Receiver question

In my house I have 2 speakers upstairs and one down. The three speakers are fairly large. I have a problem when i turn my receiver close to max it throws it into protect because I think I am getting current back into the receiver somehow (Maybe because of the length of the wire). I am using 10 gauge wire and i was wondering if I should lower the gauge or if there is something else up.

Thanks!

In my house I have 2 speakers upstairs and one down. The three speakers are fairly large. I have a problem when i turn my receiver close to max it throws it into protect because I think I am getting current back into the receiver somehow (Maybe because of the length of the wire). I am using 10 gauge wire and i was wondering if I should lower the gauge or if there is something else up.

Thanks!

Livebythesword

Double check + and - are consistent from receiver to the speakers.