Counterpoise vs triode

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bwyllie

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MA
Can anybody offer me opinions on the counterpoise vs triode for grounding connections and any explanation of the two would be helpful.

Thanks
 
Re: Counterpoise vs triode

How are the words being used, what context.

Counterpoise means equal.

Triode means equipotential cathode.
 
Re: Counterpoise vs triode

It was in a peer review of some design documents, the engineer stated he would prefer to use the counterpoise grounding method in lieu of the triode because it would be an easier connection to the lightning system as well as easier to install.
 
Re: Counterpoise vs triode

I used the triode configuration for my Ham radio station, years ago.

The triode is buried tuned radials arranged in a star. This is for a wider bandwidth.

A counterpoise is a half wave length buried radial.

I don't know how this ground concept is used in lightning systems.
 
Re: Counterpoise vs triode

These electrodes are designed to deal with the capacitance coupling between the electrode and the dirt. This coupling changes with a change in frequency.

60 Hertz systems are not as sensitive to capacity changes.

The building ground should be the common method, as indicated in the NEC.
 
Re: Counterpoise vs triode

I found some of my old papers. A triode for building ground is three rods over ten feet apart, bonded together, and installed at each building corner.

A counterpoise ground is a ground ring, with multiple rods.

The applied math indicates the triode is of lower impedance, but that is dependant on soil conditions.
 
Re: Counterpoise vs triode

thanks for the info, it is our company standars to use the triode method, not sure why, but I am trying to figure that out. Someone had mentioned that the current can't make it around a 90 degree turn in the ground ring, or something like that.
 
Re: Counterpoise vs triode

What type of system are you grounding? This sounds like a generating plant or a sub station.

I understand lightning produced current does not like sharp turns.
 
Re: Counterpoise vs triode

The project that this was recommended for is high-rise residential building.
 
Re: Counterpoise vs triode

When only 60 Hertz is involved, I would think the rebar would make a good earth connection.

When other frequencies are involved then an engineered grounding system is in order.

A grounding system for lightning dissipation should be designed to compensate for how much the capacitance coupling increases the impedance.
 
Re: Counterpoise vs triode

Counterpoise is one of those definitions that should be avoided because it has no single definition. Typically it is a radio term: "Counterpoise, a conductor or system of conductors used as a substitute for earth or ground in antenna systems".

Triode doesn't make much since either. Triode is a electron tube with a anode, cathode, and controlling grid.

"Ground Rings" and "Grids" are the simplest and most effective ground electrodes to connect lightning down conductors too.

In a high rise building, the usual method of lightning protection is just simply the structural steel framework or rebar that the building is made of. It forms a faraday cage surrounding and protecting the contents inside, and discharges lightning into the foundation much like a Ufer ground.

Are you possible referring to a "Triad" or "Tri-Pod"? That is a system of three rods layed in a triangle pattern.

[ March 06, 2004, 08:01 PM: Message edited by: dereckbc ]
 
Re: Counterpoise vs triode

Triode also means three paths to equipotential cathodes. Counterpoise is two balanced paths. These terms may not be used in the US.

[ March 06, 2004, 09:05 PM: Message edited by: bennie ]
 
Re: Counterpoise vs triode

dereckbc, that is what I am referring to and it is typically what we call for.
 
Re: Counterpoise vs triode

Here is a good site on the subject:

National Lightning Safety Institute
Just do a search on there site. There is much infomation and a lot of it is good to know.

This is what I could find on there site about a counterpoise:

single point grounding system is achieved when all equipment within the structure(s) are connected to a master bus bar which in turn is bonded to the external grounding system at one point only. Earth loops and differential rise times must be avoided. The grounding system should be designed to reduce ac impedance and dc resistance. The shape and dimension of the earth termination system is more important a specific value of the earth electrode. The use of counterpoise or "crow's foot" radial techniques can lower impedance as they allow lightning energy to diverge as each buried conductor shares voltage gradients. Ground rings around structures are useful. They should be connected to the facility ground. Exothermic (welded) connectors are recommended in all circumstances
 
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