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#129733 01/19/06 10:37 AM
Joined: Jul 2001
Posts: 599
J
JBD Offline
Member
X,

Also glad to have you back. I was looking forward to more of the "healthy" debate/discussion on this topic.
I mean like this post ain't any where near a record length yet.

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#129734 01/19/06 12:55 PM
Joined: Apr 2005
Posts: 116
X
Member
dereckbc,
OK, your last post made more sense to me. Especially: this "Although the reference ground point (the N-G bond) goes to 10,000 volts, so does our Line and neutral voltage". My thoughts were that the excess line surge needed to be re-directed, and to ground, but if the ground has the same surge current on it...Also, I'd like to add that I'm in Florida, and you know we have lot's of lightning here. But, a recent study conducted in Tampa (I'm not sure of the date of this study), shows that 80% of the surges came from equipment inside the premises, while only 20% came from lighning and the utlility. So this led to my other belief, that a surge from inside, had to be directed to the outside of the premises. And when I'm talking about a surge re-direction, I'm talking about the excess voltage that escaped the clamping devices. If I remember correctly, the article said that only 20% of the surges were from outside sources, because of how effective modern day service entrance TVSS is.

#129735 01/19/06 03:21 PM
Joined: Oct 2003
Posts: 156
D
Member
X, glad I was able to help out. FWIW you are now on to something; most transients are generated within, it is true in commercial and industrial applications. That is why the entrance TVSS is just a starting point called Class “C” application. You have to apply Class “B” and Class “A” devices to control the internally generated transients.

Again I will say earth ground has no function here either. But that is not to say the EGC does not have a function, because it does. Internally generated transients are all carried on the premise wiring. Any transients need to be returned back to its source. So how do you do that. To start you install Class “B” devices in all breaker and distribution panels. Actually the best method is to install panels with TVSS built-in the unit. Add-ons can be made worthless by the installation itself. Finally you install Class “A” device right across the point of use or at the terminals to stop (or return it) at the source.

Some more IEEE/ANSI document that you might try to get your hands on is IEEE Std C62.41 Recommended Practice on Surge Voltages in Low-Voltage AC Power Circuits, IEEE Std C62-1990 Guide and Standards for Surge Protection, and UL-1449.

#129736 01/29/06 11:00 PM
Joined: Jun 2003
Posts: 681
P
Member
This has been an outstanding thread!!!
It is good to see XEdgeX come back and explain himself...good for you... it will be good to hear your ideas in the future.
Bob- it is good to see you refraining from putting the hammer on X. Who says you are stubborn?

Derec... as usual, you are great. Each time I learn more and more from you and my peers will benefit as well.


Pierre Belarge
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