I recently wrote about the Leviton whole house circuit breaker.  These devices protect an entire building from power surges, which come in the form of lightning, or from power spikes in the electric grid.  Whole house circuit breakers are mounted near your electric panel. 

I have figured out a few tips that will make the installation more effective.  As the installation is different from house to house, some things will vary.  First off, the device needs to be mounted within a few inches of the electrical panel.  A ½” threaded-nipple works best for this.  In the case that you have a subpanel, you are left with some options. 

These devices function better the closer they are located to the main panel.  They will work with a sub panel, but only offer protection for the circuits fed off of it.  Interestingly enough, I think that if installed to a sub, these circuits would be better protected than if mounted at the main panel.  As the ground and neutral are isolated from each other in a sub panel, the surge is offered two separate routes back to ground.  However, everything fed by the main panel would not have very good protection, as the surge would travel through the main panel before hitting the sub and getting shut off, putting all of the main panel circuits in danger. 

So clearly the idea is to get this device wired as close to the main breaker as possible.  This way the surge is cut off and diverted out before the surge enters any of the branch circuits.  Levition suggests installing a whole house circuit breaker on two 20 amp breakers.  Use two separate breakers, not a two-pole. 

They go on to state that circuit spots #2 and #4 be used.  As these are the top two on the right, the surge is almost guaranteed to turn around.  Also, use as little wire as possible.  The shorter the wire run, the faster the device can dispose off the excess current.  Just because the breakers are 20 amp does not mean that you are forced to run 12 wire.  The code generally allows you to oversize wire.

As the wire will potentially be carrying an amazing amount of power, why not go with a larger diameter?  #6 or #8 THHN would be more effective when having to carry a potential lightning bolt.  The Leviton 51120-1 Surge Surpressor is a great investment, if you consider the fact that it offers protection for your appliances or devices that are not plugged in to a power strip surge protector.  However, they are of much higher quality, and offer much better protection, and cover the entire house.  This item sells for around $180.