I have a home with 150A service breaker panel that is mounted on a pole on the exterior of my home. The home was built in the 50's but the service panel was updated about 1970 with SquareD circuit breakers. I have totally gutted the interior and replaced the old cloth wiring and outlets with new romex. My question is? Can I install a secondary service panel inside my house with breakers and connect mains to the existing service panel ?:confused:

Since the original 150 amp panel will not allow a 150 amp branch circuit breaker installed into it, you will need to change the panel to a 150 amp fusible or circuit breaker disconnect switch, that will then feed the new panel inside.

Be sure you know how to connect the grounding for this system. The feeder from the disconnect to new panel will need to be a 4 wire cable.