From the system voltage and the work method, by the electrical safety programme rather than at a stores counter.

Gloves are manufactured to voltage classes with defined maximum use voltages.

Using a glove below the required class is a serious failure.

Using one far above it costs dexterity for no additional protection.

Class systems and their designations differ between markets.

The applicable standard and the site's own procedures determine the selection.

Electrical testing before first issue and re-testing at intervals set by the applicable regulations.

Gloves carry the test date, and one past its retest date is out of service.

That applies regardless of how the glove looks or how little it has been used.

Testing is done by a laboratory equipped for it rather than on site.

Records of test dates are part of the electrical safety documentation.

Letting the retest lapse is the most common failure in managing these gloves.

Rolling the glove to trap air inside and checking for leaks before every use.

A pinhole invisible to the eye is found by the air test.

It is done alongside a visual inspection for cuts, punctures, embedded material, swelling, hardening and ozone damage.

Both hands are checked, since damage to either is disqualifying.

Inflator devices exist and make the test quicker and more consistent.

It is not a formality - it is the check that catches damage occurring since the last test.

Cool, dark, unfolded and away from ozone, oils, solvents and ultraviolet.

All of those attack the rubber and degrade its insulating properties.

Purpose-made bags and boxes keep gloves in shape and protected.

Gloves stored crushed in a toolbox degrade at the fold lines.

Storing them inside out or with the protectors on is generally discouraged.

Electrical equipment producing ozone should not be stored alongside them.

Only where the applicable rules permit it, and generally not - the rubber has almost no mechanical strength.

Contact with tools, edges and abrasive surfaces damages it readily.

A damaged insulating glove offers nothing whatever.

Some regimes permit protector-free use at lower classes under defined conditions.

Where that is allowed, more frequent inspection is normally required.

The default assumption should be that protectors are worn.