RFTools Block Protector
With the block protector you can protect blocks from being harvested or affected by explosions. Use the 'sneak-select' mode on the Smart Wrench to select the protector and then just 'select' all blocks you want to protect with the Smart Wrench in 'select' mode. The maximum distance is 10. Note that the block protector will need a little amount of power per tick for every block it protects.
In addition it needs extra power when a protected block is being harvested or affected by an explosion. If there is not enough power to protect a block then the block is removed from the protection list (and will probably get destroyed). If you want to make a room to protect against more powerful explosions (like from the Wither) it is recommended to use more then one block protector to protect smaller groups of blocks. Also make sure to protect the block protector itself.
In this screenshot you can see the block protector being configured with the smart wrench:
