Temporary Protective Grounds 1

[111R]

Where is a good location to purchase temporary protective grounds?

I've read IEEE 1246-1997 and will need 350KCM copper for the available fault current and X/R ratio.

Are the clamps usually sold separate? If so, can I combine copper wire and aluminum clamps? What precautions do I need to take to prevent galvanic corrosion?

Why is copper recommended? Can I use aluminum since it's lighter for a given conductivity?

Do many utilities use undersized cable for this application just to prevent induced voltage? Sizing it for fault current with the 350KCM cable will make the grounds heavier than desired.

Thanks!

 

[Marmite]

Attached is a catalogue for a UK based supplier. Probably not much use to you directly, but it does give you an idea what is available. Cables are usually sold by length pre-terminated with a fitting either end which attaches to the line end or earth end clamp. You buy the clamp to suit the application, ie are you earthing solid bar, stranded conductor, tape etc. Over here portable substation/line earths are aluminium because they have to be light enough for a linesman to be able to apply them on the end of a pole. The conductor is pure aluminium and the PVC oversheath is clear to that any corrosion is visually apparent. If the fault level exceeds the rating of the portable earth you would need to apply multiple sets rather than specifying bigger and bigger cable as they would become physically unmanageable.

http://www.pbsigroup.com/userfiles/file/datasheets/weir/earthing.pdf

Regards
Marmite

 

[wbd]

Contact AB Chance. I work at a utility company and that is where we buy all our grounding eqpt. A websearch should give you their website and on-line catalog.

 

[HornTootinEE]

Hubbell Power systems owns Chance, who sells grounding cable, clamps, etc. They can set you up with whatever you need.

I believe Chance's clamps are dual rated Aluminum clamps-which should do just fine.

The utility I used to work at didn't undersize their grounds. It is a safety ground after all-Designed to protect the lineman working on that dead line should it inadvertently become energized.

 

[Zogzog]

If you are going to be using these on some common locations install ball studs at your ground points and use the ball style clamps, much lighter and easier to apply.

http://www.mitchellinstrument.com/b...on-switches-and-transformers.html?source=bing