SPITFIRE Set-up to Fault Locate
WARNING
Observe all safety rules for operating energized equipment up to
1000 volts.
General Information:
1. When a faulted service cable is fed directly from the transformer, it is not necessary to disconnect the secondary service cables from the transformer when fault locating from the customer's meter location. Prior to connecting the SPITFIRE to the faulted cable, a voltmeter may indicate 120 volts on the faulted conductor. Go ahead and connect the transmitter to the faulted cable because this voltage will have no adverse effect on the transmitter.
2. When a faulted cable is fed from a service mains cable which feeds a group of homes, all of the meters beyond the faulted section must be removed. The meters between the faulted section and the transformer need not be removed. The faulted cable must be identified using some type of loading device that will indicate low voltage.
 Where electronic meters are installed on mains cable systems, because of the strength and duration of the impulse, ALL meters should be removed before fault locating.

3. When fault locating street light circuits, remove all lamps and ballast's between the SPITFIRE transmitter and the suspected fault location.

Setting up the SPITFIRE to Fault Locate:

Note: It should be remembered that the SPITFIRE transmitter can deliver up to 960 plus volts dc and should be treated with respect. Electrical gloves should be worn when working around the transmitter and the service meter connections.

ALL UNAUTHORIZED PERSONS SHOULD BE KEPT AWAY FROM THE TRANSMITTER.

Remove the accessory tray and assemble the ground probes. Insert the RED and BLACK banana plugs into their respective jacks on the Detector panel.

Using a short piece of ground rod or a large screwdriver stuck into the earth, establish a ground about 8 feet away from the Transmitter and perpendicular to the cable route. Clip the SPITFIRE Transmitter BLACK lead to the driven ground.

To test the SPITFIRE operation prior to fault locating, attach the RED Transmitter lead clip to a screwdriver or piece of ground rod and push it into the earth as far away from the BLACK ground connection as possible.

Connect  the SPITFIRE Transmitter to a good 120 volt ac source and switch it "ON". Within seconds it should begin pulsing the cable sending an impulse out the RED lead and returning it through earth to the BLACK lead.

Push the detector ground probes into the ground about 2 feet apart with the RED probe closer to the RED Transmitter connection and the BLACK probe closer to the BLACK Transmitter connection. Reduce the "SENS" control knob to it's lowest setting. Depress the "ON" switch and center the meter needle with the "BAL" knob. Slowly increase the "SENS" control until a ½ to full scale deflection to the RED side of the meter is achieved. This should be accomplished with a low sensitivity setting. The meter will deflect to the RED side when the RED probe is closest to the RED Transmitter connection and to the BLACK side when the BLACK probe is closest to the RED Transmitter connection. The RED Transmitter connection, in this testing situation, is representative of a fault location.

If no signal is obtained, make these checks:

1. Remove the ground probe plugs from the detector and try deflecting the meter from side to side by turning the "BAL" control back and forth.

2. Remove the four screws on the detector panel and replace the 9 volt battery if the detector does not respond to the first test.

3. Check all connecting cables to see if any are damaged or broken. You can return it to the factory to effect repairs.

4. If all tests to the detector and cables have positive results, pack the entire unit and return it to the factory to effect repairs.

Fault Locating:

You may begin fault locating from either the transformer or the service entrance meter location.

Starting at the Transformer:

Note: When fault locating from the transformer, the service meter/meters MUST be removed and the cable ends made safe.

1. Determine the condition of all three cables using the SPITFIRE. First, remove the three cables from the transformer terminal par or connector. 

2. Set up the SPITFIRE Transmitter BLACK clip to a suitable driven ground ( i.e., Piece of ground rod, long screwdriver) about 8 feet away perpendicular from the cable starting point. The 120 volt Adapter Cable supplied with the SPITFIRE may be used at the transformer to provide a voltage source for the Transmitter. The Adapter Cable's GREEN clip goes on the GROUND, the WHITE clip goes on the NEUTRAL, and the BLACK clip goes on the 120 volt source. Connect the RED clip to the NEUTRAL conductor.

3. Assemble the Ground Probes and connect them to the Detector in their respective banana jacks. Push the probes into the earth about 2 feet apart with the BLACK probe near the transformer and the RED probe toward the cable route end or the customer's service. Depress and hold the Detector "ON" switch and center the meter needle using the "BAL" control knob. Set the "SENS" control to the second mark.

4. Switch the Transmitter "ON" while holding the Detector switch depressed. If the Detector meter deflects after the Transmitter begins pulsing, the NEUTRAL insulation has a hole in it and must be fault located. If no deflection occurs, you may increase the "SENS" control to see if the signal may be weak. If no signal is obtained, the cable is good and can be reconnected. Return the "SENS" control to the second mark. Turn the Transmitter "OFF". 

5. The RED Transmitter clip can be put on either of the other two cables to check next using the same procedure as described in paragraph 2. Repeat for the third cable. This should identify all faulted cables. Leave the RED Transmitter on one of the faulted cables to begin finding the fault. To finish got to "Finding the Fault".

Starting at the Meter Socket:

Note: When fault locating from the meter location, temporarily remove all meters as required and remove the cables from the meter socket of the suspected faulted service.

1. Determine the condition of all three cables using the SPITFIRE. First, remove the three cables from the meter socket.

2. Two methods can be used to determine if the NEUTRAL cable is undamaged.

Method A. Disconnect the NEUTRAL cable from the transformer. At the meter location, set up the SPITFIRE Transmitter BLACK clip to a suitable driven ground
(i.e., Piece of ground rod, long screwdriver) about 8 feet away perpendicular from the meter location. The 120 volt Adapter Cable supplied with the SPITFIRE may be used on one of the good 120 volt cables to provide a voltage source for the Transmitter. The Adapter Cable's GREEN clip goes on the GROUND, the WHITE clip goes on the NEUTRAL, and the BLACK clip goes on the 120 volt source. Connect the RED clip to the NEUTRAL conductor.

Assemble the Ground Probes and connect them to the Detector in their respective banana jacks. Push the probes into the earth about 2 feet apart with the BLACK probe near the transformer and the RED probe toward the cable route end or the customer's service. Depress and hold the Detector "ON" switch and center the meter needle using the "BAL" control knob. Set the "SENS" control to the second mark.

Switch the Transmitter "ON" while holding the Detector switch depressed. If the Detector meter deflects after the Transmitter begins pulsing, the NEUTRAL insulation has a hole in it and must be fault located. If no deflection occurs, you may increase the "SENS" control to see if the signal may be weak. If no signal is obtained, the cable is good and can be reconnected at both the transformer and the meter socket. Return the "SENS" control to the second mark. Turn the Transmitter "OFF". 

Method B. At the meter location, set up the SPITFIRE Transmitter BLACK clip to a suitable driven ground ( i.e., Piece of ground rod, long screwdriver) about 8 feet away perpendicular from the meter location. The 120 volt Adapter Cable supplied with the SPITFIRE may be used on one of the good 120 volt cables to provide a voltage source for the Transmitter. The Adapter Cable's GREEN clip goes on the GROUND, the WHITE clip goes on the NEUTRAL, and the BLACK clip goes on the 120 volt source. Connect the RED clip to the NEUTRAL conductor.

Assemble the Ground Probes and connect them to the Detector in their respective banana jacks. Push the probes into the earth about 2 feet apart with the BLACK probe near the transformer and the RED probe toward the cable route end or the customer's service. Depress and hold the Detector "ON" switch and center the meter needle using the "BAL" control knob. Set the "SENS" control to the second mark.

Switch the Transmitter "ON" while holding the Detector switch depressed. The Detector meter will deflect after the Transmitter begins pulsing, the NEUTRAL is still connected at the transformer and the pulse is traveling down the cable to the ground at the transformer and leaking into the earth. It will also leak from any damaged place in the insulation between the Transmitter and the transformer. You will have to fault locate toward the transformer to find any insulation damage. If the Detector indications reverse, you have passed a damaged place in the cable. To find the spot, go to "Finding the Fault". If there is no damage you will end up locating the signal origin at the transformer ground connection. Return the "SENS" control to the second mark. Turn the Transmitter "OFF".

3. The RED Transmitter clip can be put on either of the other two cables to check next. Repeat for the third cable. This should identify all faulted cables. Leave the RED Transmitter on one of the faulted cables to begin finding the fault. To finish go to "Finding the Fault".

Finding the Fault:

 Knowing the route of the cable can  be helpful during fault locating, but when using the SPITFIRE voltage gradient system, it is only necessary to know the direction from the transformer feeding the service to meter socket. When the SPITFIRE Transmitter discharges into the faulted cable, the impulse travels through the conductor and out through any holes or damage in the insulation and back through earth to the remote driven ground with the Transmitter BLACK clip on it. The electric field created from the impulse at a fault in the cable would look like a series of concentric circles if seen. Imagine throwing a stone into a pond and the concentric ripples or circles that would appear.

Now that you have identified a faulted cable from either the transformer end or from the meter socket end, you must locate the fault. The Detector "SENS" should be set for receiving a good meter deflection (½ to full scale deflection. Don't peg meter needle off the scale. It may result in Detector meter damage.) from identifying the faulted cable. Establish a straight line of sight from the transformer to the meter socket that you will walk along to locate the fault. This straight line of sight may not necessarily be the cable route, but this is not important. You will, while walking this straight line of sight, pass through the field created by the fault current leaking into the earth.
Walk about 10 feet away from your starting point and push the Ground Probes into the earth about 1-2 feet apart with the RED probe ahead of you and the BLACK probe closer to the starting point and depress the Detector "ON" switch. 

Note: If you depress the "ON" switch prior to pushing the Ground Probes into the earth, pushing the probes into the ground may cause the Detector meter to deflect. This is not an indication of the output pulse and you should wait for several seconds for the Detector circuit to settle down.

You should get a RED meter deflection. Repeat this procedure until you get a reverse meter deflection to the BLACK. This indicates you have passed the center of the energy field created at the fault location and the energy entering the probes is now greater in the BLACK probe. Slowly back up short distances at a time until the meter begins to try to move back to the RED side. At one point equal energy is entering the two probes and no meter deflection will be obtained. This is a mid point of the energy field. Draw a line halfway between the two probes perpendicular to the first path you were walking.

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Turning the probes onto this line you will continue to  probe until you obtain a meter reversal again and then slowly adjust moving back and forth until a null or no meter movement is again established and mark between the two probes here. This is also a mid point of the energy field. 

 Once you have marked this point on the ground, turn the probes perpendicular to the second path you were walking and moving in a line, zero in on the fault by moving toward the probe that the meter is indicating is closer to the fault. You should be close by the center of the field, so not much adjusting should be necessary to pinpoint the spot.

 When trying to locate faults under concrete or asphalt, it is generally necessary to wet the surface to increase it's ability to conduct the electrical field occurring at the fault.

 Three planes to intersect the energy field are all that is necessary to identify the location of a direct buried cable fault. After you have established your first null point and turn perpendicular, it is possible and probable that you will not be able to walk directly along the null point line to the fault location but you will establish a second null point. The third step of turning perpendicular and probing will bring you to the third null point or the actual fault location. The diagram below shows the three steps taken to locate the diagrammed fault.

If multiple faults are on the same cable you may find yourself marking several locations on the cable route. If the cables are all insulated, then these marks will all be faults.


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