The Glow-Wire Test — What It Checks and Which Result You Actually Need.

The glow-wire test answers a narrow question: if a part inside a piece of equipment is heated by an electrical fault — an overloaded connection, a glowing joint, a track running hot — does the material around it ignite, and if it does, does the flame sustain or die away. It is one method in the IEC 60695 fire-hazard family, and the apparatus that performs it is deceptively simple: a loop of wire, heated electrically to a defined temperature, pressed against the specimen with a defined force for a defined time. Severity is set by the wire temperature; the temperatures cited across the glow-wire methods commonly run 550, 650, 750, 850 and 960 °C, and the product standard decides which step a given part must face.

What trips teams up is not the apparatus but the question of which result they need, because the same heated wire is used to measure three different things, and they are not interchangeable.

Three measurements, one heated wire

The Glow-Wire End-Product Test (GWEPT, IEC 60695-2-11) is run on the finished product or a representative part of it. It asks whether the real object — with its real geometry, its ventilation, the proximity of its parts — withstands the wire. The answer depends on how the part is built, not only on what it is made of, which is exactly why it is a product test.

The Glow-Wire Flammability Index (GWFI, IEC 60695-2-12) and Glow-Wire Ignition Temperature (GWIT, IEC 60695-2-13) are material properties, measured on standard specimens. They are the numbers a polymer supplier quotes on a datasheet. A material's GWFI does not by itself prove the finished product passes its GWEPT — the end-product test can still be required. Reading one where the other is meant is the most common mistake in glow-wire work.

The method does not set the severity

The methods sit at the level of measurement; they do not decide which severity your part must meet. That comes from the product standard — IEC 60335 for household appliances, IEC 60598 for luminaires, IEC 60884 for plugs and socket-outlets — each of which reaches into IEC 60695 for the method and then states, for its own parts, the temperature that applies.

Where ULMEKA fits

ULMEKA designs and manufactures glow-wire test apparatus to the IEC 60695-2-10 series — the heated loop and the controlled application of temperature, force and time the method requires. Configurations beyond the catalogue, such as particular automation, specimen handling or severity ranges, are clarified at the quotation stage.