Sorry for the delay Dasersc,
Depends on what type of lightning protection system your working on.... I'll take it, that it's a conventional air conductor/down conductor system. Does the system have air conductor spikes, or will just rely on the flat tape as the air conductor??.
On this system yes it's basically Rod tests and resistance tests. If it's a new installation then a thorough air conductor routing inspection should be performed, to make sure there are no flash-over points and that there is never less than 30cm between parallel or adjacent air conductor tape or cable runs.. And to make sure that the flat tape/cable fixings are adequate in number as to be suitably braced for potential lightning strikes....
All through and crossing connections on air conductors, as well as connections to mechanical roof plant, such as AC units, roof fans and the like must be solidly made and have a maximum resistance of .05 ohms, ...which to be honest is really generous, actual readings should be much lower than this!!! These tests normally conducted with a low ohm or ''ductor'' type tester that injects current/potential into the connection/joint under test. Down conductor test points must also be tested to the same level, after the rod testing and with the removable link reinstated...
The rods in such a system all need to be tested individually, and then tested combined. The combined Ra value is the important result. In the UK that Ra value must be no more than 10 ohms (Max). Very few such installations will have such a high combined value...
Don't forget to check there is a suitable bonding connection from the LP system to the buildings electrical MET, and don't forget to disconnect that bonding during your LP system testing...
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