# Ground Fault Location Equipment for Ungrounded AC



## MDShunk (Jan 7, 2007)

Sounds like the old Metro-Tech fault finder. Does that ring a bell? That's the only one I know about that uses a headset.


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## brian john (Mar 11, 2007)

Bit confused at first (I WAS) you are looking for fault locating equipment for buried conductors.

I have used numerous systems over the years at present we are using the 3m (MODEL?) I get on Monday when I get int he office


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## bmart (Dec 28, 2011)

*Biddle set*

This is called a "thumper" for fault locating underground cable. You can hear the noise by picking up the manhole covers


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## Lone Crapshooter (Nov 8, 2008)

Try Fault Wizard www.iupcorp.com


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## Lone Crapshooter (Nov 8, 2008)

If you have a delta secondary transformer you can use two 250 volt bulbs connected in series between the phase conductor and ground. that will give you a total of 6 bulbs. If there are no grounds all 6 bulbs will glow dim. 

When you have a ground the 4 bulbs on the ungrounded phases will glow bright because there could be as much as 480 volts on them. The 2 bulbs on the grounded phase will glow very dim because they are in parallel with the grounded phase.

Because on a delta transformer all loads are balanced the way to find a ground is to place a unbalanced load on one of the ungrounded phase. Generally it is done with a heater or resistor bank. In series with the resister bank is a pulsed contactor that makes and brakes the load to create a pulse. 

With the unbalanced load pulsing you use a large jaw clip-on ammeter to find current coming back on the conduit . With this ammeter you can pinpoint exactly where the ground is. 

What I have described to you in this brief description all operates on line voltage there are no batteries involved.


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## bmart (Dec 28, 2011)

This a typical ground detection system that is used on control panels for detecting grounds on an ungrounded system

bmart


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## kf5aeo (Dec 4, 2011)

i also like the 3m dynatel for locating pipes/cables/faults find lines by either direct coupling to the pipe/cable or by induction....


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## ce2two (Oct 4, 2008)

MDShunk said:


> Sounds like the old Metro-Tech fault finder. Does that ring a bell? That's the only one I know about that uses a headset.


I work with guys who have limited experience in electrical, they use it, i never use it:no:Never had a need for one...


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