Hello:
Is there any problem with using a larger gauge wire, say 8, for an electric water heater on a dual pole 30amp breaker? That wire is already run and I didn't want to run a new one.
Thanks.

First, how do you know the cable is an 8 AWG cable? Did you look at the cable, it should be marked with its size on the sheath.

Now to answer your question, no, there are no problems using a larger cable gauge as long as the connections are made properly.

First, how do you know the cable is an 8 AWG cable? Did you look at the cable, it should be marked with its size on the sheath.

Now to answer your question, no, there are no problems using a larger cable gauge as long as the connections are made properly.

Thanks Don, the sheath has it marked as 8.

Any larger wire can be used. Make sure they are the same class and temp rating.