Insulating Gloves & PPE — IEC 60903 Manufacturer

Proof test voltage and maximum use voltage are two different numbers

A request for "a 20 kV glove" is a request for the wrong thing. On an insulating glove, 20,000 V is the AC proof test voltage; the maximum voltage that glove may be used on is 17,000 V AC. Buying on the proof test number under-specifies the class, because the proof test is the factory test and the maximum use voltage is the working limit.

Quotes and purchase orders that name only one of the two figures are the most common source of a wrong glove arriving on site. Name the class, and state the maximum use voltage you are working to.

The category letters matter as much as the class

IEC 60903 gloves carry category letters for the conditions they resist. If a glove is being used in an environment it is not categorised for, it is wearing out faster than its inspection interval assumes — and the degradation is usually visible before it is dangerous, which is why gloves are examined before every use.

The protective system has to overlap

Where an insulating glove is worn without leather protectors over it, the class goes up by one; Class 00 and Class 0 are the exception. Separately, a glove worn over a sleeve or a protector has to extend past it by a minimum distance, and that distance grows with the class — from 12 mm at the bottom of the range to 100 mm at Class 4.

Both rules exist for the same reason. If the protective system does not overlap, there is a path around the glove that its class says nothing about.

• Insulating gloves to IEC 60903 for live-line and substation work
• Insulated footwear to EN 50321-1
• High-voltage insulating suits for Class 4 live-line work
• Test certificates supplied with the order

In-service testing, and the date that is most often missed

For Class 1 to 4 gloves, the interval that matters in service starts when the glove is issued, not when it was made, and it is 6 months. Separately, a glove still unissued 12 months after manufacture has to be re-tested before it goes out at all.

So a glove can sit inside its production-date validity and already be past its in-service re-test — which is how sets end up in use for months beyond the date on the register. Class 00 and Class 0 fall outside the routine dielectric re-test; that is not the same as requiring no checks, because they are examined and air-tested before use.