I'm swapping out a heat pump package unit. The information with the system says to use a 70-80 amp breaker. The circuit supplied to the unit is on a 100 amp breaker with awg #4 copper wire (rated for 70 amps). Inside the unit are 60 amp fuses. I am uncertain as to what kind disconnect to use. I kinda of thought about any would do as long as it would carry the load. However, it seems that the only disconnects I've found in box stores are 60 amp. This is confusing since the unit supposedly is rated at 70 amps. What should I do for a disconnect? And, is the breaker on the circuit the correct one for the wire used (100 amp breaker for 70 amp wire?) Seems to me that the breaker should not be rated greater than the wire....