TVSS and Air Terminal LPS?

[wirenut1980]

Hi all, does anyone think there is any added benefit to having an Air Terminals to ground LPS system installed if there is also going to be a TVSS installed at the service equipment? I was thinking maybe the exterior LPS might prevent some kind of structural damage to the building if it was directly hit, or maybe on the off chance someone was leaning against a conductive material during a lightning strike, would the LPS help in protecting them? Having both seems like overkill to me.

 

[spence]

Re: TVSS and Air Terminal LPS?

I think you are confusing TVSS with LPS functions. The TVSS only takes care of transient voltage surges that opccur with the power distribution system. They generally protect form outside surges, but can also protect from surges generated from surge producing equipment within the building (i.e. motros, compressors, copiers, etc.). The LPS protects the building structure and roof mounted electrical equipment (HVAC equip, etc.) from Lightning hits by shunting the energy directly to ground. It is typically bonded to the electrical distribution metal conduit system where it comes within 6 feet of the LPS system. The LPS system and the TVSS's complement each other and both should provided to fully protect the building and the distribution system.

 

[wirenut1980]

Re: TVSS and Air Terminal LPS?

Spence, I guess they do serve different purposes. But in all fairness a lightning strike is a transient voltage surge event, so a TVSS would protect the interior equipment (to a degree) from lightning surges. But what you said was what I was getting at, was that the building structure itself is only protected by the exterior LPS with strike terminals. I was not aware that a TVSS protected from surges interior to the building. Very cool! Thanks for the reply.