250.30(A)(5)

[m sleem]

If i have dy 13.8/0.48 kv client transformer located in building's transformer room adjacent to room of main disconnecting mean, Should the tr's terminal bar which is indicated in EXHIBIT 250.15 be located on wall? accordingly neutral and sbj will go out from transformer to this bar.

 

[hhsting]

If i have dy 13.8/0.48 kv client transformer located in building's transformer room adjacent to room of main disconnecting mean, Should the tr's terminal bar which is indicated in EXHIBIT 250.15 be located on wall? accordingly neutral and sbj will go out from transformer to this bar.
View attachment 2552086

Is it wye to wye, delta to wye? Can you install main bonding jumper of service disco outside?

 

[ActionDave]

If i have dy 13.8/0.48 kv client transformer located in building's transformer room adjacent to room of main disconnecting mean, Should the tr's terminal bar which is indicated in EXHIBIT 250.15 be located on wall? accordingly neutral and sbj will go out from transformer to this bar.
View attachment 2552086

It needs to attach inside the transformer somewhere but where is somewhat unique to each transformer.

 

[electrofelon]

It needs to attach inside the transformer somewhere but where is somewhat unique to each transformer.

I agree. I dont see mounting the terminal bar exterior of the transformer to be code compliant and seems like a hassle anyway. The transformer likely has a convenient bonding strap built into it.

 

[m sleem]

So the clouded connections are just supplemental

 

[electrofelon]

Looks to me like that is the grounding electrode conductor that connects building steel (or whatever your electrode is) to the ground terminal with XO and SBJ inside the transformer.

 

[m sleem]

Looks to me like that is the grounding electrode conductor that connects building steel (or whatever your electrode is) to the ground terminal with XO and SBJ inside the transformer.

You mean the clouded part?

 

[electrofelon]

You mean the clouded part?

yes

 

[ActionDave]

Looks to me like that is the grounding electrode conductor that connects building steel (or whatever your electrode is) to the ground terminal with XO and SBJ inside the transformer.

I concur.

 

[electrofelon]

I dont know all the details of the premisis GES, but I consider those exterior triads un-necessary/auxiliary. Are they part of the building Grounding electrode system or are they installed just for the transformers? ITs hard to say without knowing more details about how everything is connected and what is existing.

 

[ActionDave]

That delta diagram with all three corners going to earth threw me for a bit until I e realized it was the magic triangle, power of the pyramid, mystical voodoo thing that so many high dollar engineers believe in.

 

[m sleem]

So, the other GEC goes to triangle rods is for what?

 

[electrofelon]

So, the other GEC goes to triangle rods is for what?

Voodoo? Usually when you see those triad type arrangements you are getting into grounding voodoo land.

Take a look at 250.30(A)(4) for the grounding electrode conductor and grounding electrode details, and dont forget about 250.50 and 250.58

 

[LarryFine]

So the clouded connections are just supplemental

My opinion is the building-steel connections in the clouds are required, and the triangular rod arrays are what are supplemental.

 

[m sleem]

That delta diagram with all three corners going to earth threw me for a bit until I e realized it was the magic triangle, power of the pyramid, mystical voodoo thing that so many high dollar engineers believe in.

It's the best arrangement in terms of saving spaces,

 

[electrofelon]

It's the best arrangement in terms of saving spaces,
View attachment 2552109

I would caution against focusing too much on ground resistance values, it realy doesnt matter unless you have a spec to meet. Also, I dont know where you are reading about "deep earth grounding", I thought it might be here, but I dont see that same chart:

DEEP EARTH GROUNDING

Just take everything you read from these "grounding consultants" with a grain of salt as they usually peddle mostly snake oil.

 

[m sleem]

I would caution against focusing too much on ground resistance values, it realy doesnt matter unless you have a spec to meet. Also, I dont know where you are reading about "deep earth grounding", I thought it might be here, but I dont see that same chart:

DEEP EARTH GROUNDING

Just take everything you read from these "grounding consultants" with a grain of salt as they usually peddle mostly snake oil.

It's also mentioned somewhere in Motorola spec as well as the exhibition in NEC,

It's not easy to believe you guys an disregard others.

 

[electrofelon]

It's also mentioned somewhere in Motorola spec as well as the exhibition in NEC,

It's not easy to believe you guys an disregard others.

I understand. The dirt worshipers have penetrated deeply into many areas.

There are a few specialty areas, such as antennas, tower sites, medium voltage where lower earth resistance might be beneficial, but generally there is nothing to be gained. Is there something specific you are trying to accomplish?

 

[ActionDave]

It's also mentioned somewhere in Motorola spec as well as the exhibition in NEC,

It's not easy to believe you guys an disregard others.

Oh believe me I know. Especially when it's high dollar engineers that are specing these wacko, triangle ground rod patterns and such.

The Motorola spec is a different deal than anything NEC. But it's for communication towers and similar.

 

[jim dungar]

It's the best arrangement in terms of saving spaces,
View attachment 2552109

So this table shows that a triad arrangement has more resistance to ground than 2 rods in a line. About it's only purpose, besides wasting material, is when 20' rods are installed and you cannot get 20' between them. Okay, maybe there is a place for them with standard rods and extremely difficult installation (like in rock) but there is no need for triads in the majority of the new construction where you see them specified.