Megger RCDT320 RCD Tester

Megger RCDT320 Overview

The Megger RCDT320 is a feature-rich residual current device (RCD) tester from Megger’s RCDT300 range. As well as the standard ½I, I and 5I trip-time tests, it adds ramp testing – slowly increasing the current until the device trips to measure the actual trip current – and automatic test sequences that run the full set of tests at the press of a button, saving time on routine inspections.

Covering rated sensitivities from 10 mA up to 1000 mA on standard and selective (time-delayed) devices, the RCDT320 also measures supply voltage and frequency and features a backlit display for use in poor light. With a rugged CAT III 300 V design, EN 61557 compliance and up to 2000 tests per battery set, it is a capable everyday tool for electricians and inspectors.

The Megger RCDT320 is for electricians, commissioning engineers and facility maintenance teams who verify RCDs on distribution boards and want the actual trip current, not only a pass. Its ramp test raises the current from half the rated value to about 110% in 200 ms steps and holds the trip current on the display, which Megger calls very useful for diagnosing nuisance tripping. The auto test runs ½I, I and 5I at both 0° and 180° while you stand at the RCD and reset it, then shows every result at the end. It works on 50 to 280 V supplies, so it also tests on 110 V centre-tapped site supplies, and it is three-phase safe: connected across two phases by mistake, it stays safe and undamaged.

From Megger’s RCDT300 datasheet and user guide: ranges are 10, 30, 100, 300, 500 and 1000 mA, with AC, AC selective, DC and DC selective settings (Type A, pulsed DC sensitive). 5I tests run on RCDs up to 100 mA. Test times are 2 s for ½I, 300 ms for I (2 s selective) and 40 ms for 5I (150 ms selective), and selective RCDs get a 30 s pause before the test current. Test current accuracy is −8% to −2% on the no-trip test and +2% to +8% on the trip tests; trip time is ±1% ±1 ms. The minimum supply is 71 V for 300 mA, 100 V for 500 mA and 205 V for 1000 mA RCDs. Touch voltage is checked at the start of each test against a 25 V or 50 V limit, and testing is blocked above 300 V. Frequency reads 25 to 450 Hz (±0.1 Hz to 199.9 Hz). It is CAT III 300 V to IEC 61010-1, IP54 and EN 61557-6. Eight AA cells (or NiCd/NiMH rechargeables) give about 2000 consecutive tests; it weighs 980 g and measures 203 × 148 × 78 mm.

Choosing in the range: the RCDT310 drops the 10 mA and 1000 mA ranges, ramp, auto test, backlight and frequency, and needs 100 V or more. The RCDT330 adds programmable RCDs from 10 to 1000 mA (1 mA steps up to 50 mA), storage for 1000 results and USB download.

MME is an authorized Megger representative in the UAE. See the Megger range and our RCD testers. For the entry model, see the Megger RCDT310; to store and download results, see the Megger RCDT330. For RCD, loop and insulation tests in one instrument, see the Megger MFT1741 or the Megger MFT-X1. To find the leakage that keeps tripping an RCD, see the Megger DCM300E leakage clamp. Read our guide What is a multifunction tester?

Megger RCDT320 Key Features

What the Megger RCDT320 gives you on an RCD test:

• RCD tester with ramp and auto-sequence testing
• ½I, I and 5I trip-time tests at 10, 30, 100, 300, 500 and 1000 mA
• Ramp test measures the actual trip current
• Tests standard and selective (time-delayed) RCDs; DC-sensitive support
• Voltage and frequency measurement; backlit display
• CAT III 300 V; conforms to EN 61557
• 8 × AA batteries – up to 2000 tests

Megger RCDT320 Applications

Where the RCDT320 is used:

• RCD testing during periodic inspection and commissioning
• Measuring actual trip current by ramp
• Fast full-sequence RCD verification
• Electrical contractors and inspection bodies

What’s in the Megger RCDT320 Box

What comes with the RCDT320:

• Megger RCDT320 RCD Tester
• Mains plug test lead and 2-wire test lead with prods and clips (1001-976)
• 8 × AA batteries
• Printed quick start guide, safety instructions and user manual on CD

Megger RCDT320 questions

What electricians ask before ordering:

• Does it test Type A RCDs? Yes. All RCDT300 models test Type A (pulsed DC sensitive) RCDs at ½I, I and 5I.
• Does it store results? No. Storage of 1000 results and USB download are on the RCDT330.
• Will it work on a 110 V site supply? Yes. The RCDT320 runs from 50 to 280 V, including 110 V centre-tapped supplies.

Why Buy the Megger RCDT320 from MME in UAE

MOHAMMAD MAHDI Electronics Trading LLC (MME) is a trusted supplier of Megger test and measurement equipment across the UAE and wider Middle East. We offer genuine products, competitive pricing, and knowledgeable local support to help you choose the right instrument for your application. For full technical details, download the datasheet below.

Rcdt320 Datasheet PdfPDF