INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Evaluation between earth switch and earth truck for 11kV Switchgear

Evaluation between earth switch and earth truck for 11kV Switchgear

(OP)
Can anyone throw some light on the evaluation between earth switch and earth truck for 11kV Switchgear.

I personally feel that earth switch is better, as it is integral part of the switchgear, less prone to deterioration due to external factors, storage is not a problem etc.
Less chance to commit mistake and safer compared to earth truck.

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

I am not familiar with the term "earth truck".

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

Bill, something like this. I've also seen versions which don't include the switch, they simply rack in to the board in place of the breaker.

krisys,

In my opinion a fault-making earth switch built into the gear, or a transfer earth applied through a withdrawable circuit breaker, would be preferable to an earth truck.

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

Thanks Scotty.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

"Earth truck" sounds like what my utility calls a "ground and test device," made to take the place of a circuit breaker within a switchgear cubicle. One design of GTD I've seen has two sets of insulated contacts similar to what Scotty is describing, viz., one each for the supply and load sides, brought out to a horizontally divided box with a lockable hinged lid; the two faces of the lid bear the words "BUS" and "FEEDER," allowing the GTD to be guaranteed locked in such a way as to permit access to only the intended side.

A major disadvantage of going the GTD route is when more than one feeder requires grounding simultaneously, specifically in a dense urban setting with all underground cables and no overhead conductor at all, something I've seen happen numerous times. For this reason I'd go with "earthing switches" instead, particularly in the case described.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

If you accidentally manage to close an earth switch onto live conductors it should withstand the fault long enough for protection to clear it. If you accidentally insert an earthing truck into the wrong holes it will very probably be Game Over.

Fault-rated earth switches or a circuit breaker transfer earth are much safer ways to apply an earth.

RE: Evaluation between earth switch and earth truck for 11kV Switchgear

Our GTDs normally have no intrinsic connection to ground, but I can see how the type Scotty described could have and could therefore inadvertently or, more likely negligently, be racked onto live equipment. In that case, hope the switching agent is wearing a good bomb suit, as I wouldn't want to be counting on the arc rating of the enclosure.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close