C.A.T and Genny User Guide
Contents
1. INDUCTION Induction is a convenient and quick way of applying the Genny signal to a pipe or cable where access for using direct connection or a Signal Clamp is not possible Figure 11 Figure 11 Signal Induction The following illustrations are of a typical street situation comprising four parallel lines 1m 3 ft apart and 0 5 m 1 5 ft deep When the Genny is in the upright position it radiates a signal directly below Figure 12 shows the Genny upright over one of the lines inducing a signal of 100 Assuming all lines are identical the other lines have signals of 20 6 and 3 respectively Figure 12 Genny Induction Signal Radiation Upright Position 4 4 1 C A T and Genny User Guide When the Genny is placed on its side with the Connection Socket Cover uppermost the signal covers a wider area with no signal directly below Figure 13 shows the Genny on its side and above a target line The lines have signals of 0 50 30 and 19 BETA TEANNA SR AA I LRA Nx x Figure 13 Genny Induction Signal Radiation Horizontal Position Procedure Note Always carry out the following procedure as precisely as possible Place the Genny on the ground in line with the suspected route of the target lines Switch the Genny on Switch the C A T to G and squeeze the On Off trigger Hold the C A T upright and at right angles to the suspected route Using the C A T at approximately 10 paces away from the Genny pinpoi2. C A T and Genny User Guide If the signal is lost stop and locate in a circle 1 m yd around the point where the signal was lost Figure 10 The C A T gave a response where the conductor entered the circle and if the conductor has curved another response where it leaves the circle If there is no second response increase the sensitivity to check if the signal has divided into a tee or has weakened due to increased depth Figure 10 Lost Signal Trace the conductor back to a point where it can be identified i e valve junction box street lighting column etc Warning The C A T will not locate some conductors particularly those with small cross sections or which are short such as pot ended conductors Dig with great care or use the C A T with the Genny if unlocated conductors are suspected In a noisy environment the loudspeaker can be removed from the C A T and held to the ear Always ensure the C A T is switched on and the battery test beep has sounded before holding the loudspeaker to the ear LOCATING WITH C A T AND GENNY Check the battery state by switching the Genny on if there is no loudspeaker tone or it is very slow replace the batteries There are several rules that always apply when using the Genny a Sweeping with the C A T in the Power and Radio modes indicates the position of buried conductors Check their identity by applying then tracing the Genny signal b Where possible Direct Connection or us
3. A ghost signal appears before and behind the main signal position Figure 6 Reduce the C A T sensitivity to receive only the main signal Peak Ghost O Ghost Figure 6 Mouse Transmitter Signal Peaks Locate the Mouse at 2 m intervals Equipment incorporating a Mouse is sometimes lost underground It is important to locate it before the batteries are exhausted Carry out a sweep with the C A T in the Genny mode at maximum sensitivity to locate the Mouse Page 5 C A T and Genny User Guide Page 6 3 1 3 2 3 3 C A T and Genny User Guide FUNCTIONAL CHECKS TEST AREA Using the C A T in the Power and Radio modes find a site free of interference from buried cables overhead lines etc and also clear of structural steel reinforcing bars etc TEST PROCEDURE Place the Genny on the ground and switch on Check there is an audible sound from the speaker Place the C A T flat on the ground and pointing towards the Genny Figure 7 t gt measured distance P S Figure 7 Test Configuration With the C A T switched on and set to maximum sensitivity check that the audio response which should be synchronized with the Genny audio output is as detailed in Table 1 Table 1 Functional Check Audio Responses TEST MODE DISTANCE AUDIO OUTPUT Power 1m 3ft Pulsed clearly audible Radio 6 m 20 ft Pulsed clearly audible Genny 15 m 50 ft Pulsed very high volume 26 m 85 ft Pulse
4. Connector if there is access to a live electric socket in a nearby building If there is no access point to the cable carry out a C A T sweep in the Power and Radio modes when a conductor is located induce the Genny signal and trace the conductor to a point where it can be identified Reverse the process to confirm the cable identity STREET LIGHTING If the cable cannot be found with the Power and Radio sweep carry out a C A T and Genny sweep obtain a response then induce the Genny signal and trace the conductor with the C A T Metal street lamp columns are normally bonded to cable sheaths Using a Connection Clip with a magnet fitted provides a quick and safe street lamp column connection method without the need to involve the lighting department This method is also useful for locating cables to from distribution cabinets Keep Left bollards No Entry signs traffic lights etc Concrete columns may have the cable sheath bonded to the inspection door frame If not the lighting department must make the Transmitter connection to the cable sheath Use this opportunity to gain Knowledge about the position and depth of lighting cables plus feeds to other street furniture on the same system One connection point will energize cables over a considerable area Induction can be used by placing the Genny at the base of the column Page 15 5 4 5 5 5 6 Page 16 C A T and Genny User Guide ELIMINATION If it is not possible to iden
5. Gota ESTEAN EAE ANA IEAA tedio e eta TATAA 9 PINPOINTING tosca n 9 LOCATING WITH C A T AND GENNY uii ce ceccccceecececeeececceecececeeececeaueececeuaeeeeaueeeeeaateeaaaneeesanes 11 INDUCTION lt a e Lia ad di 12 ACGTIVME SSEARCO A A ccoo ta E tros ll a tl re ts 14 USEFUL TECHNIQUES 020 A at ae at ee ees 15 PIPES PNP ND A A e 15 aN A S AS ATA PAE S PEE ile 15 STREET FIGHTING a a a a tag a a aa a ATR R A ea 15 ELIMINATION 2 a etd ee kek oe ak e ic seas 16 CONCRETE REINFORCING BARS cccccccceneececceececeaueececeaucececeuceceaueueeeeaueeeeceaeeeeaaneeesanes 16 LOCATING FEE CONNECTIONS a e cotenece laa 16 GONGESTED AREAS e coeeaeoccasschos caged A oO aa a addii 17 SIGNAL APPLICATION as 19 DIREGT GONNEGTON cuca a liz 19 ACCESSORIES ES A a a O 21 SIGNAL CLAME E a said TAS 21 ENEPLUG GONNECTOR ua bd A bea 22 GABLEAVOIDAN CE a e de nd aos 23 EQUIPMENT ORDER CODES AND SPARE PARTS cccccecseececeeeeececeeeeeeecneceeecaueeeeeeaneeees 25 CLOSSA iii ta dees de A dy evicted A dai 27 C A T and Genny User Guide C A T and Genny User Guide C A T LOCATOR 1 1 FEATURES The features of the C A T Locator Figure 1 are as follows ON OFF 1 Press and hold to use the C A T LOUDSPEAKER 2 To use in noisy environments unscrew and hold to the ear Always replace when not in use SENSITIVITY CONTROL 3 Rotate clockwise if weak signal anticlockwise if strong signal On hearing a signal reduce the sensitivity for a
6. alternative means of connection an wo ff Figure 2 Genny Transmitter Figure 3 Connection Cable Ground Stake and Ground Cable Page 3 2 2 2 2 1 2 2 2 2 2 3 Page 4 C A T and Genny User Guide OPTIONAL EXTRAS Signal Clamp The Signal Clamp Figure 4 which fits into the Genny storage compartment will apply a selective signal when connected to the Genny The Signal Clamp can be fitted to extension rods 70 cm 28 in if required Figure 4 Signal Clamp Live Plug Connector The Live Plug Connector applies the Genny signal to mains cabling via a live domestic electric socket The Genny has a safety circuit which protects the user and transmitter from the mains voltage Mouse Signal Transmitters A range of small self contained watertight transmitters for insertion into non metallic pipes or sewers Figure 5 The Mouse radiates a signal which can be pinpointed by the C A T in the Genny mode O Y Figure 5 Mouse Signal Transmitter Insert the battery into the Mouse Attach the Mouse to the drain rod using the relevant connector purchased separately Switch the C A T Function Switch to G and squeeze the On Off Trigger Place the Mouse on the ground and holding the C A T in line with it not at right angles check that the signal is being received C A T and Genny User Guide Insert the Mouse 1 m yd into the duct drain and adjust the C A T sensitivity to receive the signal
7. 1 Obtain Plans and walk the site to check for obvious signs of utilities Use safe digging practice Use the C A T upright NEVER swing it Use Power and Radio to sweep the whole area Use the sensitivity control correctly to pinpoint the conductor O oa A WO N Use the C A T again in the trench hole once you have excavated approximately 0 3 m 1 ft to locate deeper or smaller services not locatable from the surface 7 Remove the speaker when using the C A T in noisy environments 8 Remember the C A T alone cannot always locate every conductor including small services and street lighting use the Genny 9 Remember the C A T will only trace metallic conductors and not plastic pipes or fibre optic cables for example 10 Maintain your C A T and Genny regularly to ensure continued trouble free performance 2 1 2 2 3 1 3 2 3 3 4 1 4 2 4 3 4 4 4 5 5 1 5 2 5 3 5 4 5 5 5 7 C A T and Genny User Guide CONTENTS Title Page GALT L OGAT OR do lin 1 FEATURES citada a AET E E ta eal et A E AaB Ah Al td 1 GENNY TRANSMIT TERis atecick ci 3 EENTURES a ee oe AN oe 28 ae cea ate ae cle deol g chy ttt ae 3 OPTIONAL EXT BA Sin tata te ane alt se ett stented tlre hea ch elle e Ald hea peta a 4 FUNCTIONAT GHEGKS i a ie 7 FEST AREA dl is do 7 FEST PROGEDURE 024004 dao o At a e ata Dada ea dd 7 TROUBLESHOOT ING sissesoosesedtedicg poscezaadaageden A a T aa aea ia AAE AEE 7 EGA TING aa ha eet ha A a ts Md i Aa a a 9 SWEEP IN
8. C A T and Genny User Guide Revision 3 06 00 C A T and Genny User Guide Troubleshooting When reporting any problem to your Radiodetection Dealer Supplier it is important to quote the Receiver Serial Number A Warning Radiodetection Receivers detect almost all buried cables and most conductors but there are some which do not radiate signals and which Radiodetection Receivers cannot detect Radiodetection Receivers do not indicate whether a signal is from a single cable several buried side by side or one above another Live cables may not be detectable in the Power mode IF the cable is not loaded OR the cable load is well balanced This equipment is NOT approved for use in areas where hazardous gases may be present Ensure the Receiver is switched on and the battery test beep has sounded before attempting to use the loudspeaker as an earphone Ni Cad batteries should be disposed of in accordance with your Company s work practice and or the relevant law or guidelines in your country C Complies with European EMC Directive 89 336 EEC This instrument or family of instruments will not be permanently damaged by reasonable electrostatic discharge and has been tested in accordance with IEC 801 2 However in extreme cases temporary malfunction may occur If this happens switch off wait and switch on again If the instrument still malfunctions disconnect the batteries for a few seconds The Ten Golden Rules of Locating
9. L O EL eS COC CI Figure 17 Induction Signal Application Close Parallel Conductors An extension of this technique is to edge the Genny sideways until it is directly over one of the conductors This will now carry no signal and the other can be traced This technique is very effective if the two conductors are different types or at different depths Page 17 C A T and Genny User Guide Page 18 6 1 C A T and Genny User Guide SIGNAL APPLICATION DIRECT CONNECTION Direct connection is the most effective form of signal application and is suitable for connecting the Genny to a valve meter junction box or other access point Warning Should only be used on a power cable sheath by qualified personnel Procedure Plug the Connection Cable into the Genny Connection Socket and attach the red lead to the target line Figure 18 If necessary clean off paint rust or scale to ensure a good connection Figure 18 Direct Connection Configuration Clip the black ground lead to the Earth Stake which should be placed in the ground 3 4 paces away from and at right angles to the target line Alternatively the ground lead can be clipped to the rim of a valve box cover drain cover or manhole cover The earth lead can be extended using the extension cable connected to the earth clip To reduce the possibility of adjacent lines being energized decrease the signal output level by either pulling the Eart
10. d clearly audible TROUBLESHOOTING If any of the above Test Procedures give a poor result check the battery orientation Prove the fault with another C A T or Genny Page 7 C A T and Genny User Guide Page 8 4 1 4 2 C A T and Genny User Guide LOCATING SWEEPING Turn the Function Switch to Power Note The Power signal is radiated by loaded electric power cables and often found on other nearby conductors Press and hold the On Off trigger The battery test bleep will confirm the condition of the batteries Replace the batteries if necessary Rotate the Sensitivity Control fully clockwise for maximum sensitivity but reduce if there is a blanket signal across the site Define the area to be excavated and carry out a grid pattern sweep in the Power mode Figure 8 Figure 8 Sweep Grid Pattern Sweep in two directions as illustrated holding the C A T upright and by your side Walk beyond the edges of the area to be excavated PINPOINTING The presence of a buried conductor will be indicated by a tone emitted from the loudspeaker Keeping the blade vertical slowly move the C A T backwards and forwards across the conductor reducing the sensitivity for a narrower response Do not swing the C A T Page 9 Page 10 C A T and Genny User Guide When directly over the conductor and with the sensitivity level set for a narrow response rotate the C A T on its axis Figure 9 until the signal minimu
11. e Plug Connector applies the Genny signal to a live domestic power socket and via the domestic wiring system to the service cable and the supply cable in the street The signal is applied between the live and ground conductors on a 3 pin plug The connector can also be fitted with a 2 pin plug with the signal applied between the live and neutral conductors The current does not affect domestic appliances Suitable for system up to 250 V rms from dc to 400 Hz Procedure Connect the Live Plug Connector to the Genny Connection Socket and to the live domestic power socket Switch the socket and the Genny on Note Live Plug Connector contains a protection unit to protect the user and the Genny from mains voltage up to 250 V C A T and Genny User Guide CABLE AVOIDANCE The Power and Radio sweeps should locate the main conductors however some house connections streetlight cables or metal pipes may not have been detected If it is suspected that an unlocated conductor crosses the excavation site apply the Genny signal at a point where it surfaces If there is a metal street light or illuminated sign use the magnet to connect the Genny to the metal support If this is not possible induce a Genny signal and trace with the C A T At a nearby building if possible apply the Genny signal to an electricity supply cable using a Clamp or where applicable a Live Plug Connector Connect the Genny to any pipes at a nearby valve or where t
12. es from the Genny Pinpoint and mark any lines that are located Reposition the Genny at 5 pace intervals around the site searching each time with the C A T Pinpoint and mark any lines that are located Another type of search is for two operators 20 paces apart one with the Genny and one with the C A T on maximum sensitivity Figure 15 Move around the search area maintaining the 20 pace distance between operators The C A T must always be at right angles to the line of the Genny to receive the signal Figure 15 Dual Operator Active Search Page 14 5 1 5 2 5 3 C A T and Genny User Guide USEFUL TECHNIQUES PIPES Apply the Genny signal by direct connection at a meter or a tap spigot and trace with the C A T Connect the Genny signal to a valve at the junction of the branch and main and trace with the C A T Connect the Genny signal to the tracer wire on plastic water pipes Using a Signal Clamp is possible if the end of the pipe is grounded If there is no access point to the pipe carry out a C A T sweep in the Power and Radio modes if this fails to give any response carry out a C A T and Genny sweep obtain a response then induce the Genny signal and trace the conductor with the C A T CABLES Apply the Genny signal to the cable with a Signal Clamp at the meter If possible use the Signal Clamp around cables in a chamber at a distribution box or in a sub station Apply the Genny signal with a Live Plug
13. h Stake partly out of the ground or laying it on the ground A good connection is indicated by a change in loudspeaker tone If there is no tone change check the electrical contact and the earth point If necessary change the position of the earth point or tip water over it if placed in dry soil or sand Ground connections may sometimes apply the signal to other conductors or buried concrete reinforcing bars These unwanted signals can be eliminated by using the C A T 30 cm 12 in from the ground Consider the possibility of other paths the signal can take when connected to a pipe in a buried chamber for instance If the pipe is feeding machinery that has electric and water supplies the signal may feed back through these other lines Little can be done about this but always be aware of all possible paths a signal can take Tracing of the target line is normally possible from the point of connection Page 19 C A T and Genny User Guide Page 20 7 1 C A T and Genny User Guide ACCESSORIES A Warning There are potential dangers when connecting to a power cable The cable may have sheath insulation damage which could mean an accessible part of the cable may be live or may become live should a fault occur Moving the power cable to make space around it for clamping could cause stress to the insulation or conductors which could in turn cause a potentially dangerous defect either instantly or in the future In either situation the cab
14. he pipe is accessible and trace with the C A T to check if the cable crosses the excavation site Induce the Genny signal either side of any nearby covers and trace with the C A T Carry out a C A T and Genny sweep if the presence of unlocated conductors is still suspected If a conductor radiating the Genny signal is located pinpoint it then trace it across the excavation site Page 23 C A T and Genny User Guide Page 24 C A T and Genny User Guide 9 EQUIPMENT ORDER CODES AND SPARE PARTS These Part Numbers will assist when ordering spare parts and replacement equipment C A T 22 kHz 10 CG1375 33 kHz 10 CG1375 33 Genny 22 kHz 10 GG1376 33 kHz 10 GG1376 33 Signal Clamp Not allocated Extension Rod 10 EXT Live Plug Connector 3 wire 10 GG1540 LPC Ground Stake 04 AC1453N1 Ground Cable Spool 10 m yd 09 310 Connection Lead 17 GG1376E3 Genny Storage Compartment Not allocated Battery Holder C A T 04 381BH Mega Mouse Depth range 3 5 m 12 ft 22 kHz 10 SC0412 22 33 kHz 10 SC0412 33R Mighty Mouse Depth range 3 5 m 12 ft 22 kHz 10 SD0322 22 33 kHz 10 SD0322 33R Mini Mouse Depth range 1 5 m 5 ft 22 kHz 10 SE0323 22 33 kHz 10 SE0323 33R It will be necessary to order the relevant rod connectors for the above Mouse Signal Transmitters Radiodetection also supplies high performance instruments for locating buried pipes cables and sewers and for pinpointing problems on buried lines Page 25 C A T and Genny User Gu
15. ide Page 26 GLOSSARY Active Signal Conductor Direct Connection Induction Passive Signal Sensitivity Target Line C A T and Genny User Guide A signal applied to a conductor with a Genny A long metallic cable or pipe Application of an active signal to a conductor using the Connection Cable Signal Clamp or Plug Connector A signal radiated from the internal antenna of the Genny which is induced into a conductor and re radiated A signal that occurs naturally on a buried conductor such as 50 60 Hz power energy or very low frequency radio energy The ability of the C A T to receive a signal e g with increased sensitivity weaker signals can be received A selected metal cable or pipe to which the Genny signal has been applied and which is to be traced or pinpointed using the C A T Page 27 C A T and Genny User Guide Radiodetection Ltd Western Drive Bristol BS14 OAZ UK Tel 44 0 117 976 7776 Fax 44 0 117 976 7775 email sales uk radiodetection spx com http www radiodetection com S Radiodetection Riser Bond Dielectric Technologies Bicotest Pearpoint Telespec Radiodetection products are under continuous development and are subject to change without notice Part No 90 UGO05EN3 All rights reserved
16. ing a Signal Clamp is preferable to Induction when applying the Genny signal c Whenever possible apply the Genny signal at an access point where the conductor can be positively identified d For a further identity check after normal location reverse the procedure by inducing the Genny signal on to the conductor and tracing it back to the original point of application Tracing and pinpointing the Genny signal with the C A T requires similar techniques to those used in the Power and Radio modes Adjust the C A T sensitivity in the Genny mode for a narrow response Sensitivity will need a periodical increase as the signal strength reduces when tracing further away from the Genny Never assume a buried cable or pipe is straight and trace every part of the length to be certain Page 11 4 4 Page 12 C A T and Genny User Guide The Genny signal will sometimes transfer on to unwanted conductors therefore never assume that the first response to a signal is the conductor to be traced Increase the sensitivity to maximum and carry out a sweep in a circle around the Genny Note the position of all conductors leaving the circle Repeat the sweep reducing the sensitivity until the C A T is sensitive enough to locate only one conductor which is almost certainly the conductor with the applied signal Note A signal which has leaked on to a conductor near the surface can appear to be stronger than the actual signal on a deeper conductor
17. le is inherently dangerous and not to be touched with or without a Signal Clamp SIGNAL CLAMP The Signal Clamp safely applies a transmitter signal to a pipe or a live cable of up to 76 mm 3 in diameter without interrupting the supply in situations where direct connection is not effective In Figure 19 A B C and D are four conductors from a common source When a signal is directly connected to D the other three share the signal proportionally according to the line impedance causing A to have a greater signal strength than D Figure 19 Direct Connection Current Comparison If conductor D is energized with a Signal Clamp Figure 20 all the current is through D and then divided among the others D is clearly identifiable as the conductor with the strongest signal Figure 20 Clamp Connection Current Comparison Page 21 7 2 7 2 1 Page 22 C A T and Genny User Guide Note Two conductors would have equal signal currents The conductor must be grounded at both ends Do not use the Signal Clamp at the end of a pipe or cable unless the end is grounded Do not make a ground connection from the Genny when using the Signal Clamp Procedure Plug the Signal Clamp into the Genny Connection Socket Place the Signal Clamp around the pipe or cable ensuring the jaws are closed Figure 21 Switch the Genny on Figure 21 Clamp Connection LIVE PLUG CONNECTOR The Liv
18. m is found the blade is now in line with the conductor Figure 9 Finding Signal Minimum Sometimes it is not possible to define a zero and a maximum signal over a buried conductor particularly when it is radiating a strong Power signal Raise the C A T to 0 5 m 20 in from the ground reducing the sensitivity if necessary then rotate to find the minimum signal Trace the conductor out of the area marking the position as required with chalk or paint Rotate the Sensitivity Control fully clockwise and resume sweeping the area following the grid pattern There is often but not always a Radio signal originating from distant radio transmitters that penetrates the ground and is re radiated by buried conductors When the Power mode sweep has been completed select the Radio mode and again sweep the area following the grid pattern Ensure that the ground is well marked where all buried conductors were located before excavation commences Local know how plans and knowledge about the presence of buried conductors will help when locating as they indicate what to expect Moving the C A T steadily from side to side and adjusting the sensitivity as necessary follow the line so that the audible signal is heard when over the conductor and not at either side The response from the conductor can suddenly reduce or disappear due to a A curve b A depth change c A Tee connection d A break in or the end of the conductor 4 3
19. narrow response to pinpoint the conductor FUNCTION SWITCH 4 Selects three locating modes Power Detects 50 60 Hz energy present on most buried conductors IN Radio Detects re radiated radio energy if present on buried conductors Genny Detects conductors radiating the applied Genny Transmitter signal BATTERY COMPARTMENT 5 Open the access cover using screwdriver coin to replace 8 LR6 AA 1 5 V alkaline batteries 4 AS a Figure 1 C A T Locator Page 1 C A T and Genny User Guide Page 2 C A T and Genny User Guide GENNY TRANSMITTER 2 1 FEATURES The features of the Genny Transmitter Figure 2 are as follows ON OFF BUTTON 1 When the On Off button is pressed with no accessory connected to the Genny an induction signal is radiated CONNECTION SOCKET 2 When an accessory is connected to the Genny Connection Socket the signal is applied via the accessory Induction mode is automatically disabled LOUDSPEAKER 3 To reduce the audio level press and hold the On Off button at switch on BATTERY COMPARTMENT 4 Open the access cover using screwdriver coin to replace 4 LR20 D 1 5 V alkaline batteries STORAGE COMPARTMENT 5 Opened by releasing the two end clips and contains a Connection Cable for connecting the Genny directly to a conductor a Ground Cable on a reel and a Ground Stake for making ground connection Figure 3 Connection Clips with magnets fitted provide an
20. nt the position of the target line The Genny signal can sometimes be received directly by the C A T causing incorrect pinpointing information To eliminate this unwanted signal reduce the C A T sensitivity If difficulty isolating this direct signal from the signal on the target line continues move a further 10 paces away from the Genny and resume pinpointing It is possible with practice and by carefully reducing the C A T sensitivity to pinpoint a target line radiating the Genny signal when the C A T is only 5 paces from the Genny It is usually possible to induce a signal on to a line at the base of a street light beside a meter or where the cable or pipe enters the ground Adjust the Genny position for the best signal application Always place the Genny over the cable or pipe before it enters or after it leaves the chamber never on a cover In congested areas the precise positioning of the C A T and Genny is important To help discriminate between two adjacent lines keep the C A T stationary and inch the Genny sideways Page 13 C A T and Genny User Guide 4 5 ACTIVE SEARCH This technique can be used to check for the presence of lines not radiating Power or Radio signals Figure 14 o Figure 14 Active Search Place the Genny on its side with the Connection Socket Cover uppermost The Genny will energize all lines to either side but not lines running directly below Carry out a search with the C A T at least 10 pac
21. sate If the response suddenly reduces or disappears check with increased sensitivity if necessary that the conductor has not curved or gone deeper If not there is probably either a Tee connection Figure 16 or an insulation fault if insulated The actual point of the junction is generally midway between the point where the signal starts decreasing and the where it levels out Figure 16 Tee Connection Response 5 7 C A T and Genny User Guide CONGESTED AREAS A wide response from the C A T usually indicates the presence of two or three conductors buried close together The limit of obtaining separate responses from close together conductors radiating the same signal is normally limited to a distance apart marginally more than 85 of their depth Usually the position of the two close together conductors can be defined by using the C A T in its two passive modes A telecom cable radiates a stronger Radio signal than an energized power cable and careful pinpointing over the area first in Power mode then in Radio mode will define separate responses very close to each other Close together conductors can also be defined using the Genny If two close together conductors are running parallel the Genny can be positioned across each of them enabling the C A T to pinpoint the other The Genny should be used horizontally with the Connection Socket Cover uppermost and be placed symmetrically across the route of the conductors Figure 17 E
22. tify the conductor being searched for carry out either a C A T Power and Radio sweep or a C A T and Genny sweep across the area and mark the position of all conductors that are located Trace them back to a point where they can be identified and mark each line with its identity telecom power water etc The procedures just described are some of the more common methods for obtaining results with the C A T and Genny but there are many others CONCRETE REINFORCING BARS Any longitudinal piece of metal in the ground will re radiate ac signals such as Power Radio and Genny In the case of reinforcing bars or lengths of discarded cable the signals are virtually undetectable at normal depths 50 cm 20 in at which cable and pipes are buried When near the surface they are easily detected and form unwanted interference when tracing a deeper conductor The solution is to lift the C A T approx 30 cm 12 in above the ground The distance to the shallow reinforcing bars is increased by a factor of around ten so their effective signal is reduced by the same and they are no longer detected by the C A T LOCATING TEE CONNECTIONS Apply the Genny signal to the conductor Using the C A T trace the conductor with the sensitivity adjusted to give a very narrow response Moving away from the application point the signal will gradually reduce as the Genny signal leaks off the conductor making it necessary to periodically increase the sensitivity to compen
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