Protective Ground required?

[Skogsgurra]

Hi, just testing the mooload service to make pictures available in the fora. But also asking a question:

Is protective grounding required when a structure is completely passive? In this case (an insulator on display at the Hoover dam) there is nothing connected to the insulator chain or the structure where it hangs. Nonetheless, there is some sort of ground wire attached to the structure and to the handrail surrounding it.

I imagine that there has been some discussions before attaching this wire. The way it was done tells that it was not taken very seriously.

Comments?

http://www.mooload.com/file.php?file=files/1130791649/Protective

Ground 1.jpg

Gunnar Englund

http://www.gke.org

 

[itsmoked]

Comment... Your link is kaput!

 

[Skogsgurra]

Sorry upload didn't work. No spaces allowed in URL. Try again:

http://www.mooload.com/file.php?file=files/1130792221/Protective_Ground_1.jpg

Gunnar Englund

http://www.gke.org

 

[davidbeach]

How far away is this from live HV circuits? Could be close enough to develop induced voltages.

 

[BJC]

I thik it's there to ground the handrail.
The insulator string is there for an exhibit I take it ( a close up look for the tourist).
The handrain could be anchored to the concrete with some drop in anchors and not coneectedt to rebar.
The handrail ground itself may be an educational feature the display.
Where are you now, how was/is the trip?

 

[Skogsgurra]

Thanks for your comments!

No, I do not think that it is there because of induced voltage. There are several other metallic structures about the same size. And they are not grounded with an extra wire. I think that someone just thought that "this looks electric - better ground it"

And, as you can see, the wire hasn't been laid with great care. The connections are very haphasardly made. It is a "let's get done with it" installation.

Otherwise the trip was a total sucess! Jraef and zdas04 took care about us in San Francisco and Farmington. Had dinner with them and their wives. Nice to meet people that you have come to know and respect via the eng-tips fora. And the south-west is a great part of USA. We have a couple of 1 GB memory sticks filled with pictures. It will take some time to sort all this out.

Gunnar Englund

http://www.gke.org

 

[stevenal]

There's a real transmission tower in the background. I'm sure that too many people were complaining about the harmless static shocks they were getting off the handrail, and this was the quick and easy fix. The other structures may be grounded to rebar below, be out of reach of the visitors, or be oriented differently to the lines. See

http://www.transmission.bpa.gov/NewsEv/pdfs/LivingAndWorking.pdf

page 2.

 

[itsmoked]

Nice article stevenal!