Electrical test equipment according to NEN-EN 50191

In the Netherlands, NEN-EN 50191:2010 (Installation and operation of electrical test equipment) is the standard for setting up test equipment, for both low and high voltage. The requirements come up most with high voltage. How to set this up safely and correctly is a question we often get when we supply test systems.

Suppliers and manufacturers of (high-voltage) test and measurement equipment state in their data sheet or manual that the system meets EN 50191. Is that still true once you unpack the tester, set it up and start using it? No.

In Germany, free guidance on this standard is available: DGUV Information 203-034 (formerly BGI 891), Errichten und Betreiben von elektrischen Prüfanlagen (in German). It does not replace the standard, but it gives a good picture of the requirements for setting up test systems safely.

With the right test and measurement systems you can integrate test equipment into production in line with the standard.

EN 50191 is the European standard for the installation and operation of electrical test equipment. It sets requirements for:

• the layout of the test zone: guarding, signalling and access control;
• the electrical safety of the test setup: earthing, emergency stop and interlocks;
• the qualification of operators and responsible staff;
• working procedures and risk assessments.

A manufacturer can declare that its test instrument meets EN 50191. But the standard covers the whole system, not just the instrument. Once you put the tester to work in a production line, laboratory or service workshop, you are responsible for that system.

The CE marking and the supplier’s declaration of conformity cover the tester as a stand-alone product. The company that commissions the equipment is responsible for commissioning the test system so that it complies with (local) directives and applicable standards. Once you build the tester into a test setup, you are responsible for:

• the risk analysis of the complete test setup, including fixture, cabling, interlock and the device under test (DUT);
• marking out the test zone, with a physical and visible separation of the high-voltage zone;
• emergency stops that are within reach, tested and documented;
• earthing and residual current protection in line with local installation requirements;
• written operator instructions and authorisation.

This applies to a simple handheld safety tester just as much as to a fully automated test line.

A safe test setup has at least:

• clear visual and/or physical guarding of live parts during the test;
• an emergency stop that de-energises the high-voltage output immediately, even if the control system fails;
• a discharge circuit for capacitive DUTs after the test;
• interlocks that stop the high-voltage test from starting until the test zone is safely closed;
• a documented working procedure for each test type, with acceptance criteria;
• periodic verification of the measuring chain and the safety components.

IONIO provides training on working safely with (high-)voltage test equipment according to EN 50191. The training is practical: you learn to apply the standard to your own test setup, including risk analysis, zoning and documentation. We can add an explanation of the test systems you already have.

The training is meant for operators and for the people ultimately responsible for tests that fall within the scope of EN 50191: production managers, safety officers, test engineers and operators of safety testers, hipot testers or automated test lines. You can take it at our premises in Kootwijkerbroek or at your own site.

Questions about the training, or would you like advice on your test setup? Contact us.

See also the EN50191 high voltage and safety training. Read more about standards at IONIO.