Re: Surge suppression
The canister type you mention is a class A type TVSS. Class A is the smallest device and used to protect a branch circuit. You will need at least a class B or C device to protect a sub-panel or service panel.
My first question is this a sub-panel or a main service panel? If it is a service I would recommend a class C device. Sub-panel class B device.
When selecting a TVSS device look at the modes of protection, and surge rating in amps.
For class C device select a device that offers L-L, L-N, L-G, and N-G modes with at least 160K amps.
Class B, look for L-L, and L-N protection modes with at least 100K amps. Avoid L-G and N-G modes.
There are several manufactures out there (ACT, Dihn, LaMarche, Northern Technologies). Choose one that has hybrid modules meaning they have a combination of MOV, SAD, and or Gas. Gas absorbs the most energy, but take too long to operate. SAD is the fastest, but cannot handle large current. MOV's are fast and can handle large currents, just not as fast as SAD, or as much current as gas tubes. Best combo is MOV/SAD or SAD/GAS.
From an installation point of view twist the leads and keep them as short as possible. Lead length grater than 12 inches make the units worthless. Select a knock-out adjacent to first breaker nearest feeder or service. The best installation tip is buy a panel that has TVSS buit in using a Kelvin-Clamp method, or a device that is in front of the service or panel using Kelvin-Clamp. A Kelvin-Clamp is basically a bus with the protection modules bolted onto the bus with no leads.
[ April 07, 2003, 09:55 PM: Message edited by: dereckbc ]
