Ground choke?

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jes25

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Midwest
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Electrician
A while back there was a thread and somebody mentioned something about a ground choke. Today I had an inspector mention this as well. I am not sure what this is and what will happen if you do "choke" a wire. I want to make sure I dont do it whatever it is!
:confused:
 
Re: Ground choke?

If you "choke" a conductor it will eventually turn purple and pass out. :p

When you pass a single conductor through a metallic raceway without bonding the two together, a high frequency, high current event like lightning will cause the raceway to act as an inductor thus increasing the impedance of the current path quite significantly. I have seen some estimates that claim an inductive choke can reduce the current flow by as much as 97%.

Perform a serch for this topic in the grounding vs bonding forum to obtain lots of good info on this phenomenon. The math is pretty extensive but the theory is fairly basic.
 
Re: Ground choke?

Thanks for the reply. Would the choking effect be caused by a nonmetallic raceway and a die cast or steel locknut.

[ November 30, 2005, 09:24 PM: Message edited by: jes25 ]
 
Re: Ground choke?

reduce the current flow by as much as 97%.
The above comes from the IEEE green book.
Its possible the locknut could become hot from induction, not sure about that
 
Re: Ground choke?

actually, they do
they are used in my jurisdiction at corrosive locations.

[ November 30, 2005, 09:53 PM: Message edited by: augie47 ]
 
Re: Ground choke?

Originally posted by jes25:
Well they dont make plastic locknuts :D
Click to expand...
Yes they do. They're on Carflex Conns. :D

CarflexConn.jpg


[ November 30, 2005, 09:56 PM: Message edited by: paul ]
 
Re: Ground choke?

Bryan

"If you "choke" a conductor it will eventually turn purple and pass out."

I got a good chuckle from that statment. :D


I wonder. Do the manufacturers choke the wire until it turns purple and then stop choking it just before it passes out? :D

Yeah, it is starting to get late.
 
Re: Ground choke?

Bryan,
When you pass a single conductor through a metallic raceway without bonding the two together, a high frequency, high current event like lightning will cause the raceway to act as an inductor thus increasing the impedance of the current path quite significantly.
Click to expand...
The experiments on this issue were done at 60 hertz.
Don
 
Re: Ground choke?

So I am still a little unsure about the diecast locknut, do I need to go back and change the one I have installed in a nonmetallic receway.
 
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