Switchgear Grounding

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A-1Sparky

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I need to tie some wires into the buss bars of a gear. I have a 15.5 kv switch that powers a transformer that then powers the gear I need to work on. The 15.5 kv switch has 3 positions: open, closed, and ground. Do I need to ground this switch in order to safely work on the gear, or can I just put the switch to the "open" position? Is the "ground" position of the switch for bleeding residual voltage? If not, what is the "ground" position for? Thank you in advance.
 
No offense to you, but if I did not know the answer to such a question there is no way I would be touching that switch.

And BTW, I don't know the answer to the question.
 
This is relatively new gear (installed 2 years ago) and I haven't had to work on any of it yet. The old gear just had "open" and "closed" positions, so I'm a little thrown off by the "ground" position.
 
can you post pictures of the gear?

im sure zog will chime in but if im not mistaken the ground is used to ground the phases if power comes back on it trips whatever is feeding it and doesnt hurt the workers. i could be wrong but im pretty sure i remember hearing about grounding busbars while they are deenergized in order to safely work on them. ive seen 4/0 jumpers in catalogs for this purpose.
 
You should be familiar with personal protective grounding methods, and qualified on the system and voltage that you are working on. Your work should be performed between grounds. Just my 2 cents.

Jim
 
MY gut opinion is locked in the ground position.

But the correct answer is are you trained in working on/in/and around HV gear?
Do you have the proper PPE?
Do you have the literature on the gear to read up on this question or contact the manufacture?


No one was trying to slight you, but in many of our experiences the majority of electrical accidents are a result of a lack of training and knowledge regarding the equipment to be serviced.
 
According to the NFPA 70E, a ?Qualified Person" is one who is trained and knowledgeable of the construction and operation of the equipment or the specific work method, and be trained to recognize the hazards present with respect to that equipment or work method.

And, liek Brian said, can't tell you much without the nameplate info from the switch.
 
Ground Position

Ground Position

In my experience, that kind of switch is usually feeding a capacitor bank. The ground position bleeds off the capacitors.
 
petersonra said:
No offense to you, but if I did not know the answer to such a question there is no way I would be touching that switch.

And BTW, I don't know the answer to the question.
Click to expand...

I fully agree with you. this is serius stuff. It can make you go boom if you don't know what you are doing.
 
Just a quick question, do you know what is being grounded? I have seen the ground switch ground the feeder, with the transformer being disconnected; ground the transformer with the feeder being disconnected; grounding both the transformer and the feeder. So depending on how the ground switch is connected what kind of protection is provided. As said before if you don't kn ow and are not properly trained you shouldn't be operating the ground switch on that particular device.
 
A-1Sparky,

I work for a private utility and we have these switches on our 13.8kV generators. In our case, they are wired so that in the "Ground" position we are disconnected from the grid and earthing the generator leads so we can do maintenance on the unit.

However, I absolutely agree with Richxtlc that you need to do your homework on this system and find out how it was actually wired. You'd be really sorry if it turns out that the "Ground" position earths the energized line-side conductors in your system. Medium voltage is no place to make guesses and assumptions.

-John
 
Switchgear grounding

Switchgear grounding

In the ?ground? position, the line side is disconnected and the ?load? terminals (connected to the capacitor bank) are grounded. Those responding to your inquiry expressing concern that you may be getting in over your head are right. If you haven?t had experience with this kind of gear, and don?t make sure you completely understand how it functions in this location, you could be in for big trouble.
 
Project Manager

Project Manager

Sometimes the gear has a ground position to bleed off any static electricity on the bussing! Make sure you get some literature from the manufacturer of the switchgear ( Square D, G.E., Siemens, Cutler-Hammer, etc.).
 
Thanks to all of you who tried to help answer my questions. For those of you who just chimed in to say that I'm not qualified to work on such a system, that is exactly what I'm trying do do--become qualified. That starts with asking people who may be more experienced than me with this type of switch gear. For you pencil-pushers out there...I appreciate your concern for my safety, but stick to your computers and try not to get your hands dirty. I don't plan on working on this gear until I fully understand how and what it operates. I've operated and worked on numerous MV switches in the past...just none like the aforementioned one. I'll update those of you who may be interested what I found out about this switch: It's a 15.5 kv-rated switchway with vacuum interrupters and SF6 gas insulation. It has a main disconnect which de-energizes all 3 switchways via manual interruption or electronic interruption in the case of a fault. Also, each of the 3 individual switchways can be de-energized by rotating the puffer switch to the "open" position. The "ground" position can be used to bleed off any stored capacitor voltage or to ground the incoming MV cables. I still need to contact the contractor who installed the gear to determine how the switch was wired before I de-energize it and work on the gear. Thanks again to those of you who actually tried to help.
 
A-1Sparky said:
Thanks to all of you who tried to help answer my questions. For those of you who just chimed in to say that I'm not qualified to work on such a system, that is exactly what I'm trying do do--become qualified. That starts with asking people who may be more experienced than me with this type of switch gear. For you pencil-pushers out there...I appreciate your concern for my safety, but stick to your computers and try not to get your hands dirty. I don't plan on working on this gear until I fully understand how and what it operates. I've operated and worked on numerous MV switches in the past...just none like the aforementioned one. I'll update those of you who may be interested what I found out about this switch: It's a 15.5 kv-rated switchway with vacuum interrupters and SF6 gas insulation. It has a main disconnect which de-energizes all 3 switchways via manual interruption or electronic interruption in the case of a fault. Also, each of the 3 individual switchways can be de-energized by rotating the puffer switch to the "open" position. The "ground" position can be used to bleed off any stored capacitor voltage or to ground the incoming MV cables. I still need to contact the contractor who installed the gear to determine how the switch was wired before I de-energize it and work on the gear. Thanks again to those of you who actually tried to help.
Click to expand...


Around here,,,,,the power company has a saying. "If it ain't grounded, it ain't dead"............hence your switch
 
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