TVSS options

[tjmurf]

My question is about TVSS manufactures and technologies.
We are in the process of replacing / upgrading the main services into our Waste Water treatment plant. The designing engineer has specified a sole manufacture for the TVSS equipment. The only major difference I find between the device specified and what the contractor wants to install is the MOV's are or have selenium in them and it requires a special cable to connect. The cost of this device is substantially more and is a separate device that hangs on the wall. The contractor wants to use a device that is internal to the switch board. Any thought on manufactures or technologies would be appreciated. I have kept names out but have no problem mentioning them. Just don't want to brand bash.

Thank You
Terry Murphy

 

[dpc]

There has always been a lot of marketing hype used by some manufacturers of these devices.

AFAIK, none of these "special" products has been shown to be anymore effective in the real world than a standard MOV surge suppression device, properly sized and installed. The suggestion that a special cable is required is highly suspicious and made my BS detector start to jingle.

It's critically important to keep the TVSS as close as possible to what is being protected and to keep the ground connection as short and as straight as possible.

We typically suggest the GE surge protection products, but there are other good products available.

 

[alehman]

Be sure to look for compliance with UL 1449 *2nd edition* or even 3rd edition. There had been some rather dramatic failures of earlier devices, so UL made the failure requirements more stringent. Be sure it is rated for the the available fault current.

Several manufacturer's sell special cables for connecting their devices. I agree these have snake-oil overtones.

I'm with dpc in that I've not seen any independent tests that convince me one is better than another. You can try to compare surge current rating and clamping voltages, but those numbers are always suspect. Do look at protection modes (line-ground, line-line, etc).

Oh, and keep the wiring *short*. Mounting in the switchboard can help with that, but may make maintenance/replacement more difficult and may limit available manufacturers.

 

[YuriSarcas]

ASCO makes one that can be mounted in the switchboard if there is room. I included a link and it should give you all the information you need.

http://www.asco.com/cgi-bin/redirect.pl?/product.html