Split off of this post. JasonLion
First understand what a protector does. Does it block or absorb a surge? Protectors that do that do not claim to protect from destructive surges. The Intermatic protector does not do protection. It is only a connecting device to what must absorb hundreds of thousands of joules - earth ground.Originally Posted by jragan
Surges do damage by finding earth ground maybe via your controller. A surge connected to earth before it gets to a controller does not damage that controller. That means every wire inside every incoming cable must connect to earth. Either directly (ie a coax cable). Or via a protector (AC electric, telephone). Every cable must connect low impedance (ie less than 10 feet) to that same earthing electrode.
So view your situation as if one structure or two. For example, if pools and house are the same structure, then a 'whole house' protector must be where the main breaker box makes a short as possible (ie 'less than 10 foot') connection to earth. All other incoming wires must also make the same earth connection.
Or consider the pool and house as two separate structures (ie more than 20 feet apart). Then the pool wire must enter at the main box to be earthed by the main 'whole house' protector. And the other end of that wire must be earthed at the pool controller by its 'whole house' type protector. Also with a 'whole house' type protector. Any wires from the pool to its controller also must be earthed either directly or via a 'whole house' type protector. Only then will a surge current not find earth destructively via the controller (ie from pool, through controller to earth via something inside the house).
That incoming wire to earth can be via a protector inside a controller. So the controller must have a short (low impedance) connection to an earthing electrode. A safety ground wire (ie from remote panel to controller) is not an earth ground. That is only a safety (or equipment) ground. Your concern is connecting a surge to earth via the earth ground. And again, low impedance means short, no sharp wire bends, and that wire not inside metallic conduit.
Either a surge is earthed before entering a building (or pool controller). Or that surge is inside hunting for earth destructively via appliances. This concept was so routine and so well proven that damaging lightning strikes are considered a human mistake. If damage does occur, an investigation starts with the earth ground - the item responsible for absorbing surge energy.
Effective protectors (ie the Intermatic) must connect to what does protection. If that connection from Intermatic to earth goes up over a foundation and down to an electrode, then the Intermatic is compromised. That connection must be low impedance (shorter, no sharp wire bends). It must go through the foundation and down to an electrode. Because distance to single point earth ground is critical for effective protection.
A professional's application note demonstrates the concepts. In that case, the two structures are a building and radio tower. Each has its own single point ground. To make both grounds better, grounds are interconnected. The note shows even underground wires must be protected before entering either structure.
http://www.erico.com/public/library/fep ... ncr002.pdf
Too many confuse a protector with protection. A protector (Intermatic) is simple science. The protection (earthing) is an art.