The Tinker & Rasor Model APS Holiday Detector is an all-purpose electrical inspection instrument which maintains a given inspection voltage in spite of the electrical load on the circuit.  It is recommended for use on any pipe diameter as well as on flat surfaces when such surfaces are coated with a highly electrical resistance material, and when the surface beneath the coating is electrically conductive.  The detector works equally well on damp or dry surfaces, and is especially desirable where humid conditions prevail.  


Open the shipping carton and make note of the various accessories.

(A) Instrument
(G, H) Battery (LiFePO4)
(I) Battery Charger (115v or 230v)
(D) Screwdriver
(B) Ground Cable (20’)
(1) Wand Handle (18”) Not shown, under APS

C) Compax Connector for Spring Electrodes (F) Adapter, use with SPY® brand spring electrodes
(E) Inspection Paddle, silicone-rubber, 4” (1) Carrying case (Not shown)
(1) Electrode of Choice* (Not shown)


INSPECTION should be made upon receipt.  If damage has occurred during shipment, file a claim with the carrier immediately. If it is necessary to contact your supplier or the manufacturer concerning damaged or missing items, be sure to include the serial number, purchase order number, and invoice number of the instrument in question. * Instrument ships with electrode of choice. Electrode may be Full Circle Spring Electrode (up to 36” pipe diameter), Half Circle Spring Electrode (up to 8” pipe diameter) or Silicone Rubber Electrode (up to 8” pipe diameter) or Wire Brush Electrodes (up to 8” width). Larger size electrodes and additional electrodes available at additional cost. 

NOTE: Additional accessories may ship in separate packaging.

Unpacking and Reviewing your Tinker & Rasor Holiday Detector Before Every Use

  • Make certain the inside of the case is clear and dry.

  • Inspect each component for damage, such as cables, instrument & wand handles.  

  • Make sure all of the electrodes are clean.

  • Verify the unit is fully charged.

  • Verify that the output voltage is correctly set to the coating manufacturers recommend inspection voltage.

  • If manufacturers requirements are not stated, NACE International, SSPC or ASTM Standards can be followed.


WARNING! This is a HIGH VOLTAGE device capable of producing an electrical shock if not properly grounded and/ or operated in accordance with the instructions and procedures prescribed in this manual!


If you have a pacemaker, life critical electronic medical devices or any medical condition effected by High Voltage, DO NOT use this type of equipment. Only trained and responsible personnel should operate high voltage equipment. Alert all personnel nearby prior to testing and display warning signs. It is important to realize you are now using a high voltage, low energy holiday detector.  Tinker & Rasor holiday detectors, APS & AP/W, are designed to generate between 800 to 35,000 volts, pulsating DC.  While these voltages are high, the energy emitted is well within US, OSHA guidelines. Rubber or plastic gloves and non-conductive footwear can minimize potential shock. Keep in mind that the shock prevention effectiveness of the rubber or plastic glove and footwear is limited to the condition of their protective surface. Make sure your gloves and footwear are in good condition and have no holes or tears. Most Portable Holiday Detectors are limited to finding defects in nonconductive coating materials. Testing should ONLY be conducted clear of personnel not involved in the testing procedure. Personnel operating Holiday Detectors should always be aware of their environment and the safety limitations imposed by same. Operator should have an alert assistant, to ensure that all unauthorized personnel are kept clear of the testing area. 
DANGER!!! Portable Holiday Detectors create an arc or spark. Use of a Portable Holiday Detector in or around combustible or flammable environments can result in an explosion. When operating in any potentially hazardous area, consult with the plant or site safety officer before proceeding with a holiday detection test in any potentially hazardous or suspect area. 
“on” but not in use, Tinker & Rasor Pulse Type Holiday Detectors, APW and APS will generate radio frequency emissions which are within the limit defined by the Electromagnetic Compatibility Directive. Due to its method of operation however, the APW and APS Pulse Type Holiday Detector will generate broadband RF emissions when the unit is generating high voltage or when a spark is produced at the electrode. It is therefore recommended that the user does not activate the high voltage within the vicinity of sensitive electronics or radio equipment. 
WARNING! USE CAUTION WHEN RAINING. If it is raining then there is a safety concern for the operator. Surface water on the sub straight is usually not conductive enough to transmit voltage, but almost any contaminant will cause water to become more conductive. If water covers the wand handle while connected to the APW Power-Pak or the APS Instrument, then the operator could become the return path for the high voltage. While the output voltage will cause harm to a healthy person, according to OSHA, your environment must be taken into consideration when operating this type of equipment.  For example; if you are standing on top of a flag pole and receive a jolt of high voltage, it will most likely cause you to jump, and you will fall off the flag pole. Stay Alert, Stay Aware and Stay Alive. 
If it isn’t raining, but the coating surface is wet, Tinker & Rasor Holiday Detectors are designed to minimize the effects of damp or wet coatings. In extreme cases, “ghost” holidays might be witnessed, should a continual path of water reach a holiday. If this continues, dry the sub straight and continue testing.   It is important to note that all accidents are preventable.  Take caution when using Tinker & Rasor holiday detectors or any other high voltage test equipment. 


  • Remove all accessories from the shipping carton.

  • Connect high voltage wand handle to front of instrument and ground cable to detector handle (insert and twist clockwise). Never connect or disconnect the cable or wand when the instrument is turned on.

  • Attach electrode to the high voltage wand handle assembly and apply to the structure to be inspected.  The electrode should always make intimate contact with the surface under inspection.

  • The Model APS Holiday Detector is now ready to turn on.

  • Turn the instrument ON by holding the safety switch handle firmly against the instrument handle. (Instrument handle has rubber grip), then pressing the “ON” button.

NOTE: The instrument will turn OFF when the safety handle is released.

  • Use push buttons to select the HIGH or LOW range.  Remove the dust cover with the supplied screwdriver, and adjust the voltage setting, using the digital display for reference. The instrument must be ON for this operation.

  • The instrument will “remember” the last HIGH or LOW and voltage setting selected, after being turned OFF and then ON again.

  • If holiday detection testing is to be done in a high noise environment, the instrument audible alarm may be set to the LOUDER volume using the appropriate push button found near the speaker on top of the unit. Similarly, to lower the volume, push the LOUD button.

  • The instrument is now ready to use.


The Model APS Holiday Detector includes an integrated voltmeter displayed on the front panel of the main instrument.
The LCD of the voltmeter measures and displays the output voltage of the holiday detector. This display gives the user the ability to tune the APS to a specific voltage within the 800v –8,000v Low range and the 3,500v – 35,000v High range. Voltages increment in 100v steps. Because the Model APS includes this integrated peak reading voltmeter, it is not suggested that an external peak reading voltmeter be used with this instrument. Most external peak reading voltmeters currently available are not as accurate as the integrated voltmeter of the APS, and will not show as accurate results.


The Model APS voltmeter is accurate to +/- 5% of the output voltage, as shown on the LCD display on the instrument panel. It is recommended that the Model APS follow an annual calibration cycle to ensure the instrument is in good working order and that the LCD of the integration voltmeter is accurate. 


A good ground return system for both the pipe and the detector will always provide the best and most reliable inspection.  The pipe to be inspected must be grounded from the bare pipe to earth at some point along the pipe.  If individual joints of the pipe are to be inspected that are not electrically connected, each joint must be grounded.     The speed of the electrode's travel along the pipe should never be excessive, since faulty inspection may result.   Occasional checks of the detector operation should be made, particularly if no holidays are being found.  This can be accomplished by testing for the spark and signal at the edge of the coating where bare pipe exists or by touching the probe end to the bare pipe and noting the length of the spark and the visual and audible signal effectiveness.  If the visual and audible signal do not both occur when the spark discharges from the electrode into a known holiday, the ground return (i.e. the path between the metallic pipe and earth and the earth to the ground trail of the detector) is of high resistance.  In this case, a better ground is required and a direct connection between the metal pipe and the ground wire may be necessary.  This type of grounding is extremely uncommon unless the soil is very dry (if using a grounding rod) or the detectors output is low. 

Correct voltage output for a given thickness of coating has long been a matter of controversy.  However, recent formulas have been suggested which may be used as a guide for correct peak voltages on various coating thickness.  The calculation is as follows: 

V  =  K √ T    WHERE V  =  Peak voltage in volts.

T  =  Thickness of fusion bonded epoxy (FBE) coating in mils (not including outer wrappers). 
K  =  Constant of 1,250 for coatings over 30 mils and 525 for fusion bonded epoxy coatings under 30 mils.

NOTE: Formula taken from NACE International Standard RP0274, RP0490. These standards and other available for free download to members at: 

These formulas, when applied to a coating of 3/32” thickness and with a constant of 1,250, would indicate an applied voltage of 12,500 volts peak or a coating of 16 mil thickness with a constant of 525 would indicate an applied voltage of 2,100 volts.  A common practice used in setting inspection voltages in the field is to adjust the output voltage by visual observation.  It is the general consensus that spark discharge at least twice the thickness of the coating will give adequate inspection voltage and compensate for any irregularity in coating thickness and grounding conditions.  If this practice is desired for determining inspection voltage, it should be done while the electrode is in the normal operating position and under actual grounding conditions. The formulas and suggestions for setting voltage are supplied as a guide, and are not necessarily recommended by the manufacturer of this detector.   Consult the coating manufacturer for recommended voltage applications. 


The Model APS comes with two (2) batteries. The lithium-ion battery should be charged after each use. The Model APS will indicate when the battery voltage is low, by a slow blinking of the Green Power LED, instead of providing a steady glow. The battery charger has an LED. RED color LED indicates the battery is being charged. GREEN color LED indicates that battery is fully charged. GREEN color LED also means that the battery is on trickle charge, and can be left in this condition. The charger can be used with 110v / 240v AC. It is an auto sensing charger that can be used throughout the world. Older Battery and Charger 
Beginning with APS serial number 827, the battery charger included with the instrument has a slide switch that will allow the charger to operate from 115V AC or 230V AC. The factory setting of this slide switch is set for 115V AC, which is correct for the US. To adjust for 230V AC, slide the switch so that 230V AC Shows. 
The new battery charger also now comes with a standard computer –style AC cord that plugs into the battery charger and the wall outlet. When the charger is being used outside of the US, a different plug configuration may be required. This type of computer –style cord should make it easy to find an appropriate AC cord throughout the world. 
Older Model APS units were supplied with either a 110V or 240V charger with a hardwired cable. Check the packing list or invoice of your order to verify which battery charger was included with your Model APS. 
The battery charger has a special plug that is designed to fit into the connector on the side of the battery, so that polarity of the connection is not an issue. 
The battery charger has an LED on its side. This LED will glow steady while charging the battery. The LED will begin BLINKING when the battery is fully charged. 


   1. Cleaning:  Keep the instrument clean and dry.  Clean the instrument case with a soft, damp cloth, then wipe dry.  Do not use solvents such as lacquer thinner, methyl ethyl keytone, etc.


2.  Voltage Output Checks

  •  In case of LOW output voltage:

    • Check the LED indicator for the HIGH or LOW Range selector, to ensure the instrument is in the correct Range. 
      Check the display for voltage output. Voltage displayed is in kilovolts. (22,000volts = 22.0 on display) 
      Check green ON LED. If flashing, this indicates a low battery voltage. 

  • ​In case of NO output voltage:

    • ​Check green ON LED. If flashing, this indicated low battery voltage.

    • Check for poor connection on battery terminals. 

    • Check ground cable and wand handle connections. 


Holiday Detectors returned to the factory for repairs should be sent TRANSPORTATION PREPAID.  In most cases the detector can be repaired and returned the same day it is received at the factory. WHEN ORDERING PARTS FOR YOUR DETECTOR OR REQUESTING FURTHER INFORMATION ALWAYS GIVE THE DETECTOR’S SERIAL NUMBER. 

Holiday Detectors returned to the factory for repairs should be sent TRANSPORTATION PREPAID.  In most cases the detector can be repaired and returned the same day it is received at the factory. WHEN ORDERING PARTS FOR YOUR DETECTOR OR REQUESTING FURTHER INFORMATION ALWAYS GIVE THE DETECTOR’S SERIAL NUMBER. 


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