MEGGER CBT3 Residual Current Device Tester User Guide SAFETY WARNINGS Continuity of protective conductors of new or modified installations must be verified before carrying out RCD tests. The instrument must never be connected across two phases of a 3 phase supply. If either neon fails to indicate when the CBT3 is connected, connections and fuses must be checked and any defects rectified. The instrument should not be used if any part of it is damaged. When testing high energy system circuits other than by mains supply socket, HSE recommends the use of fused test leads. Replacement fuses must be of the correct type and rating. Safety Warnings and Precautions must be read and understood before the instrument is used. They must be observed during use. NOTE THE CBT3 MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS Symbols used on the instrument Caution: refer to accompanying notes Equipment protected throughout by Double Insulation (Class II) Equipment complies with relevant EU Directives
R R MULTI-AMP BIDDLE MEGGER R R GENERAL DESCRIPTION The CBT3 is a portable, compact, robust instrument designed to test the operation of A, B and C type Residual Current Devices (RCDs). Single phase RCD tests may be performed via a socket supply (incorporating the RCD under test) or by direct connection to the RCD terminals with the optional 3 wire fused test lead set. Each separate phase of three phase circuit RCDs can be similarly tested to Neutral and Earth. Never connect the instrument directly across 2 phases. The neons illuminate to show a correct connection to the supply, and that the instrument and (if fitted) optional 3 wire test lead fuses are intact. Membrane toggle buttons are used to set up the test configuration, and a test is executed by pressing the membrane Test push. The time taken for an RCD to operate is displayed (autoranging) on the 4 digit LCD. Phase/Earth Voltage neon Setting Indicators TYPE A B C P-N P-E 150 I 2 I ma 5I Phase/Neutral Voltage neon Polarity setting indication RCD TYPE Toggle Button MEGGER CBT3 Digital LCD RCD Current Toggle Button TEST Push Button 500 300 100 30 10 6 POLARITY Toggle Button RCD TRIP CURRENT Rotary Switch RCD TESTER ma Testing is inhibited if: 1) Neutral - Earth voltage >50 V. Display shows. 2) Thermal protection device operates to protect the instrument from overheating if used repeatedly without time for heat dissipation. Display shows. 3) Time limit for the selected test expires.
PRE - TEST CONFIGURATION Before performing a test, CBT3 must be configured for the specific Type of RCD, its rated Current, Type of test, and Polarity (0 or 180 ). Default settings are for a type A RCD at test current 1 2 I, occuring at. RCD Rating selection Six standard current ratings are selectable with the rotary switch. Stand - by position is used to reset the microprocessor. The display remains blank in this position. RCD Type selection Pressing the TYPE button toggles the indicator to select the type of RCD. A Ordinary General Purpose type device conforming to BS 4293. B Selective device designed to operate with a time delay after the appearance of a residual current. Also known as Type S or time delayed RCD. C General device to IEC 1008-1 which have specific pass / fail criteria. Default setting is for Type A RCD. Test Current selection Pressing the I button toggles the indicator to select the test current as follows:- Test Current Test Description 1 2I No-trip test at half the rated current of the selected RCD. Checks if the RCD is subject to spurious nuisance tripping, or not. Max Time 2 secs I 150 ma 5I Trip test at the rated current of the selected RCD. (BS7671). For RCD s rated at not more than 30 ma. Test current of 150mA must cause the RCD to trip in less than 40ms. (BS7671). Fast trip test to check that the RCD operates in a time much faster than for the normal trip time. (BS4293). A - 2 secs B - 500 ms C - 300 ms 40 ms A - 200 ms B - 150 ms C - 40 ms Test current default setting is for the 1 2 I No trip test. Note:- Selection of incompatible settings are automatically defeated. e.g. The 5I test cannot be performed for a 300 ma or 500 ma rated RCD. Polarity selection The choice of polarity enables the trip time to be measured accurately, as some RCD s perform differently if the current occurs at the beginning of a positive or negative cycle. Test current is always applied during a zero crossing at 0 or 180. It is recommended that tests at both and are performed, the final value being the larger of the two results. Pressing the button toggles the indicator to select the polarity. Polarity default setting is for when the test current is applied at 0 of a positive cycle.
Neon Indication Both P-E and P-N neons illuminate to show a correct connection to the supply, and that the instrument and optional test lead set fuses are intact. (Voltage required to illuminate neons >100 V). Illuminated neons should be taken as voltage indication only and not as complete proof of continuity. If neon P-E illuminates, but P-N does not, either:- i) Neutral is open circuit. ii) Phase and earth are exchanged. Check and rectify iii) All 3 connections are incorrect. defects If neon P-N illuminates, but P-E does not, either:- i) Earth is open circuit. ii) Phase and Neutral are exchanged. Check and rectify defects iii) All 3 connections are incorrect. It is not possible to perform tests if the P-E neon is not illuminated. If both neons fail to illuminates, either:- i) Phase is open circuit. Check and rectify ii) Neutral and Earth are open circuit. defects iii) Instrument (or supply) fuse(s) are ruptured. Failure of neons to indicate must not be taken as proof of a dead circuit, as the instrument or test lead fuses may be ruptured. It is possible for capacitance between conductors to cause the neon(s) to illuminate, even if the Neutral or Earth is open circuit. OPERATION Refer to Safety Warnings before using the instrument To reduce possible interference, it is recommended that all loads normally supplied through the RCD are disconnected during testing. Making a test - Power plug method 1. Insert the test lead supply plug into a socket of the installation under test. 2. Confirm that neons P - E and P - N are both illuminated. 3. Select the appropriate RCD current rating. 4. Accept the default configuration, or re-set as appropriate. 5. If possible, observe the RCD under test and press the TEST button. 6. Compare the displayed value with the RCD manufacturers specification. Making a test - 3 wire test lead method 1. Firmly connect the Red crocodile clip to Phase, the Black crocodile clip to Neutral and the Green crocodile clip to Earth. 2. Confirm that neons P - E and P - N are both illuminated. 3. Select the appropriate RCD current rating. 4. Accept the default configuration, or re-set as appropriate.
5. Observe the RCD under test and press the TEST button. 6. Compare the displayed value with the RCD manufacturers specification. TEST RESULTS DISPLAY FOLLOWING A TRIP Trip Display Test Current 1 2I I 150 ma 5I A Type B Type. If time <130 ms -. If time <50 ms - C Type TEST RESULTS DISPLAY FOLLOWING A NON - TRIP No Trip Display Test Current A Type B Type C Type 1 2I I 150 ma 5I Standard RCD Trip Current Ratings: Display: Resolution: Accuracy: Time measurement Test current Operational Voltage: Temp. Coefficient: SPECIFICATION 6mA; 10 ma; 30 ma; 100 ma; 300 ma; 500 ma 4 digit L.C.D. (max reading 1999 ms) <1 second - 0,1 ms Between 1 and 2 seconds - 1 ms ± 1% ± 1 ms ± 10% over operating voltage range 230 V -6% +10% r.m.s. 50 Hz <0,03% / C for time measurement <0,01% / C for test current Temp. Range: Operating: Storage: Thermal Protection: -5 C to +40 C (90% RH at 40 C non Condensing) -25 C to +65 C (90% RH at 40 C non Condensing) Thermal cut-out will prevent overheating caused by excessive repetitive testing. Disconnect and allow to cool.
Replaceable Fuse: Mains cord Plug 13A H.B.C. BS1362 (25 mm x 6mm) Non - Replaceable Fuse: Instrument 1A (F) 250 V, ceramic H.B.C. (20 mm x 5 mm). Fitted for overall protection, this fuse is not replaceable by the user. No response from the instrument when there are no wiring faults, and the mains plug and 3 wire test lead fuses are intact, is likely to mean that this fuse has ruptured. The instrument must be returned to the manufacturer, or an approved agent for repair. Safety: Meets the requirements for double insulation to IEC 1010-1(1995) EN61010 (1995) at 230V installation Category II with mains power cord and plug and installation Category III with 3 wire fused test leads. E.M.C: Meets EN 50081-1 and EN 50082-1(1992) Dimensions: 175 mm x 95 mm x 57 mm Weight: 400g Cleaning: Wipe disconnected instrument with a clean cloth dampened with soapy water or Isopropyl Alcohol (IPA) Relates to transient overvoltage likely to be found in portable equipment and appliances. Relates to transient overvoltage likely to be found in fixed installation wiring. Power cord If the power cord plug is not suitable for your type of socket outlets, do not use an adaptor. You should use a suitable alternative power cord, or if necessary change the plug by cutting the cord and fitting a suitable plug. The colour code of the cord is: Earth (Ground) Yellow/Green Neutral Blue Phase (Line) Brown If using a fused plug, a 13 Amp fuse to BS 1362 should be fitted. Note: A plug severed from the power cord should be destroyed, as a plug with bare conductors is hazardous in a live socket outlet. Note Users of this equipment and or their employers are reminded that Health and Safety Legislation require them to carry out valid risk assessments of all electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as from inadvertent short circuits. Where the assessments show that the risk is significant then the use of fused test leads constructed in accordance with the HSE guidance note GS38 Electrical Test Equipment for use by Electricians should be used.
ACCESSORIES Supplied Part Number User Guide 6172-303 Power cord test lead with plug to BS1363/A 6131-970 Zip up Carry Case 6420-083 Optional Test lead set with fused probes and 3 crocodile clips 6231-522 REPAIR AND WARRANTY The instrument contains static sensitive devices, and care must be taken in handling the printed circuit board. If an instrument s protection has been impaired it should not be used, but sent for repair by suitably trained and qualified personnel. The protection is likely to be impaired if for example; it shows visible damage; fails to perform the intended measurements; has been subjected to prolonged storage under unfavourable conditions, or has been subjected to severe transport stresses. NEW INSTRUMENTS ARE GUARANTEED FOR 1 YEAR FROM THE DATE OF PURCHASE BY THE USER. Note: Any unauthorized prior repair or adjustment will automatically invalidate the Warranty. INSTRUMENT REPAIR AND SPARE PARTS For service requirements for MEGGER Instruments contact :- AVO INTERNATIONAL or AVO INTERNATIONAL Archcliffe Road Valley Forge Corporate Center Dover 2621 Van Buren Avenue Kent, CT17 9EN Norristown, PA 19403 England U.S.A. Tel: +44 (0) 1304 502243 Tel: +1 (610) 676-8579 Fax: +44 (0) 1304 207342 Fax: +1 (610) 676-8625 or an approved repair company. Approved Repair Companies. A number of independent instrument repair companies have been authorised for repair work on most MEGGER instruments, using genuine MEGGER spare parts. Consult the Appointed Distributor / Agent regarding spare parts, repair facilities, and advice on the best course of action to take. Returning an Instrument for Repair If returning an instrument to the manufacturer for repair, it should be sent freight pre-paid to the appropriate address. A copy of the invoice and of the packing note should be sent simultaneously by airmail to expedite clearance through Customs. A repair estimate showing freight return and other charges will be submitted to the sender, if required, before work on the instrument commences.
AVO INTERNATIONAL Archcliffe Road Dover Kent CT17 9EN Tel: +44 (0) 1304 502100 England Fax: +44 (0) 1304 207342 4651 S. Westmoreland Road Dallas TX 75237-1017 U.S.A. Tel: +1 (800) 723-2861 (U.S.A. only) Tel: +1 (214) 330-3203 (International) Fax: +1 (214) 337-3038 PO Box 9007 Valley Forge PA 19484-9007 Tel: +1 (610) 676-8500 U.S.A. Fax: +1 (610) 676-8610 MEGGER SA 29 Allée de Villemomble 93340, Le Raincy Paris Tel: +33 (1) 43.02.37.54 France Fax: +33 (1) 43.02.16.24 This Instrument is manufactured in the United Kingdom. The Company reserves the right to change the specification or design without prior notice. Part No 6172-303 - Edition 1 - Printed in England - 11CC