Extech MG500 10 kV Insulation Tester

Name: Extech MG500 10 kV Insulation Tester | Seven Star LLC
Brand: Extech
SKU: MG500

MG500 is the Extech digital high voltage insulation tester for motors, cables, transformers and switchgear. It generates test voltages from 500 V to 10 kV DC in 500 V steps, measures insulation resistance from 800 kOhm up to 500 GOhm, and calculates the Polarization Index (PI) and Dielectric Absorption Ratio (DAR) automatically. It is supplied in a rugged hard case.

Spot checks and trend tests on high voltage insulation

Insulation resistance falls slowly as windings and cables age, absorb moisture or collect dust, so maintenance teams test at a voltage matched to the equipment rating. The MG500 offers 20 voltage steps and four preset buttons for 1 kV, 2.5 kV, 5 kV and 10 kV, with the test voltage defaulting to 2500 V on power-up. A bargraph shows the voltage as it ramps, soaks and decays.

The manual defines DAR as the resistance at one minute divided by the resistance at 30 seconds, and PI as the resistance at 10 minutes divided by the resistance at one minute. The tester computes both, shows the elapsed timer and, when a test ends, automatically discharges the capacitive or inductive circuit and shows the discharge on the bargraph.

Features stated in the datasheet and manual

Test voltage 500 VDC to 10 kVDC; resistance 800 kOhm to 500 GOhm with dynamic auto-ranging.
EnerSave mode limits test duration to save battery energy; a longer test is started by holding the test button.
Live circuit warning when more than about 500 V AC or DC is present on the leads; low battery indicator and automatic battery test at power-up.
CAT III-300V rating; optional fused test leads and a leakage guard lead for surface leakage.

Technical specification

Measurement specification (datasheet and manual)

Parameter	Specification
Insulation resistance range	800 kOhm to 500 GOhm, auto-ranging; resolution 1 kOhm
Basic accuracy	± 5 % (manual: ± (5 % + 2 digits))
Test voltages	500 VDC to 10 kVDC, 20 ranges in 500 V steps; presets 1 kV, 2.5 kV, 5 kV, 10 kV
Output voltage tolerance	+20 % to -5 % of nominal unless current limited; voltage is lowered automatically if output current is too high
Output power limit	1 W
Short-circuit current	0.83 mA at 1 kV and 2.5 kV; 0.62 mA at 5 kV and 10 kV
PI and DAR	Calculated automatically
Safety category	CAT III-300V; IEC/EN 61010-1:2001

General specification

Parameter	Specification
Display	2 x 16 character alphanumeric dot matrix (OLED) with bargraph
Power source	Eight 1.5 V C alkaline cells; battery life 40 hours (no load, at 10 kV)
Test leads (silicone)	Red with integrated blue guard lead, 3 m (120 in); green ground lead 127 cm; blue leakage guard lead 127 cm
Operating conditions	0 to 40 C (32 to 104 F); below 80 % RH; altitude up to 2000 m
Storage conditions	-10 to 60 C (14 to 140 F); below 80 % RH
Dimensions and weight	330 x 260 x 160 mm (13 x 10.2 x 6.3 in); 3.6 kg (7.9 lb)
EMC standards listed	EN 61326-1, EN55011 and EN 61000-4 series as printed in the manual
Warranty	Two years from date of shipment; six months on sensors and cables

Choosing test voltage and test mode

The datasheet lists a single order code, MG500. Select the test voltage from the equipment rating and your own site procedure; the manual does not prescribe voltages, so follow the cable, motor or transformer maker guidance. A short EnerSave test is the default; press and hold the start button for more than three seconds to run the longer DAR and PI test of ten minutes.

Be aware that the datasheet gives the EnerSave test time as 10 seconds while the operating text in the manual mentions 5 seconds; treat the exact time as approximate.

Safety and connection notes from the manual

Always de-energise and isolate the circuit, and never test live circuits. The manual warns that devices such as power factor correction capacitors, low-voltage mineral-insulated cables, electronic dimmers and fluorescent ballasts can be damaged by 10 kVDC, and that rubber gloves, insulating mats and trained personnel are expected when working near high tension systems.

Connect the green earth lead to the earth side of the insulator and the red line lead to the other side; the blue guard lead is wrapped around the insulation, for example with a copper wire at the centre, to divert surface leakage. Do not remove the leads until the HOLD indicator appears after discharge.

Typical uses in Gulf plants

The manual shows tests on AC and DC motors, power tools, single and multi-conductor cables, transformer windings, contactors and circuit breakers, insulating gloves and blankets. General engineering note: motors and cables in dusty, humid coastal plants often show falling readings between outages, so logging PI and DAR values per asset gives a trend that single spot readings do not.

Related Extech items

For a lower-voltage tester see the other insulation and resistance testers on the Extech range; for temperature checks of motor housings see the IR400 mini IR thermometer. Browse the portable test and measurement category.

Frequently asked questions

What voltages can the MG500 apply?

From 500 VDC to 10 kVDC in 500 V steps, with preset buttons for 1 kV, 2.5 kV, 5 kV and 10 kV.

How high a resistance can it read?

Up to 500 GOhm, with auto-ranging from 800 kOhm and 1 kOhm resolution.

Does it calculate PI and DAR?

Yes. PI and DAR are calculated automatically during the long test, using the resistance ratios defined in the manual.

What does it need for power?

Eight 1.5 V C alkaline cells, giving about 40 hours of life with no load at 10 kV according to the manual.

Is Seven Star LLC an Extech distributor?

No. Seven Star LLC is an independent supplier in Muscat that sources Extech products on request.

Documents and quotation

The official Extech datasheet and user manual for MG500 are hosted on this page for download. Seven Star LLC is an independent supplier in Muscat; send your quantity and delivery location through the quotation form and we will quote this item. Please confirm the exact order code, supply voltage and output options against the documents before ordering. More related products: product category.

Meters, testers and inspection tools

The Extech range includes multimeters and clamp meters, insulation and resistance testers, power analyzers, thermometers, light and sound level meters, anemometers, tachometers, vibration meters, moisture meters, borescopes and water quality meters. Each datasheet and user manual lists ranges, accuracy, safety category and ordering codes, and many models are listed with NIST-traceable calibration versions ordered by adding -NIST to the part number.

Frequently Asked Questions