[NLRS] Transient Suppressors

[Bud Patten]

GM All:
I want to place surge suppressors across a 230V ac line.   I'm thinking one from each side of the line to ground and one across the line.  The question is what should the voltage ratings be for the suppressors?   I was looking through the DigiKey catalog and found some Panasonic ZNR types that look promising but I'm a bit confused by the voltage specs.   I understand that the voltage rating for the device across the line will be twice that of the ones from line to ground.   If any of you guys have some experience in this area, I could really use some input.

73,
Bud