Chauvin Arnoux CA 6240 10 A Micro-Ohmmeter

CA 6240 is a portable micro-ohmmeter from Chauvin Arnoux that measures very low resistances with a test current of up to 10.2 A, using four-wire Kelvin connections for contact resistance, busbar joints, cable lugs and winding checks.

Low-resistance measurement with a 10 A source

A micro-ohmmeter injects a direct current through a joint and reads the voltage drop across it, so that microohm and milliohm values can be resolved that an ordinary multimeter cannot see. The CA 6240 works in six ranges from 5 µΩ up to 399.9 Ω, with an accuracy of ±0.25 % ±2 points in every range, and it selects one of four test currents: 10.2 A, 1.02 A, 102 mA or 10.2 mA.

The manual describes it as a portable instrument in a site case with a rechargeable battery and built-in charger. It has an eight-position range switch, a five-key keypad, one START/STOP button and a back-lit 100 x 57 mm LCD that shows two values at once, for example resistance together with current or the voltage across the joint.

Features given in the manual

• The current direction can be reversed with the ±I key, and the instrument then shows the average of R(+I) and R(-I), which cancels thermoelectric effects.
• Clip detection: disconnecting a clip stops the test, and attaching it to the next object starts a new one without pressing START/STOP.
• Memory for 100 results, organised by object (OBJ) and test (TEST), with read and erase functions.
• Optical/USB cable and the MOT application software to configure the instrument and transfer stored data to a PC without erasing it.
• Rapid charging to 90 % in about 3 h, and the instrument can be used while charging.
• Electrical safety to IEC/EN 61010-2-030, with resistance measurement to IEC 61557-1 and -4.

Technical specification

Resistance ranges

Measurement details

General specification

When to choose this model

Pick the CA 6240 when the job needs a true 10 A test current, for instance verifying that bolted busbar joints, circuit-breaker contacts or welded connections stay within the resistance limit set by the equipment maker. For protective-conductor continuity at 200 mA, an installation tester is the better tool; a micro-ohmmeter is for sub-ohm values where contact quality matters.

Using it on site

The object under test must not be live. Connect the two cables to the four terminals, attach the Kelvin clips to the object, choose the range and press START/STOP. The manual gives a strong warning for inductive loads such as transformer windings: never touch or disconnect the leads until the test has stopped and at least ten seconds have passed, because the stored energy can produce an arc.

The delivery condition is a cardboard box with a carrying bag holding two 10 A Kelvin clips on a 3 m cable, a 2 m power cord, the optical/USB cable and quick start guides in each language. Charging must be done between 0 and 40 °C.

Applications

Maintenance teams in power stations, substations and industrial plants use micro-ohmmeters to check busbar joints, switchgear contacts, winding connections and cable terminations after installation or during shutdowns. In Gulf conditions, heat cycling and dust make connection checks a recurring item on maintenance schedules, and a stored result for each joint gives a baseline for the next shutdown.

Accessories and spares

The manual lists double probe tips, miniature Kelvin clips, a CA 846 thermo-hygrometer, an optical/RS cable and a GB power cord as accessories, and fuses (5 A, 500 V, 6.3 x 32 mm) as spares. See other instruments in the Portable Test & Measurement category.

Selection and installation notes

Electrical test instruments are selected from the test voltage or current, the range and the safety category. Check the leads and the instrument before each use, make sure the circuit is isolated and proved dead before a resistance or insulation test, discharge the test object after an insulation test, follow the site safe-working procedure and keep the calibration current according to your quality system. Record the test conditions with each result.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Frequently asked questions

What test currents does the CA 6240 provide?

10.2 A, 1.02 A, 102 mA and 10.2 mA, depending on the range in use.

How does it deal with thermoelectric voltages?

Press ±I to reverse the current. The instrument then shows the average of the two readings.

Does it include measurement leads?

Yes. Two 10 A Kelvin clips on a 3 m cable, a power cord and an optical/USB cable are in the delivery condition.

How many results can it store?

It stores up to 100 measurements, which can be transferred to a PC with the MOT software.

Does Seven Star LLC act as a Chauvin Arnoux distributor?

No, we are an independent supplier in Muscat and supply Chauvin Arnoux items on request rather than acting as a Chauvin Arnoux channel partner.

Documents and quotation

Download the official Chauvin Arnoux user manual for CA 6240 from this page. As an independent supplier based in Muscat, Seven Star LLC supplies Chauvin Arnoux items on request: use the quote form with the quantity you need. Check every value in the document against your own specification before you order. Browse similar items in the category.