When work is done on or near live electrical equipment, the insulating rubber glove is the worker's primary barrier between the hand and the voltage. Like any protective device, it only protects within the limit it is rated for, and with gloves, the rating that matters most is the voltage. Getting that rating right, every time, is the whole point.
Gloves are rated by class, for a maximum voltage
Electrical insulating gloves are classified, under IS 4770 in India, and the matching international standards IEC 60903 and ASTM D120, into classes, each with a defined maximum use voltage:
| Class | Maximum use voltage (AC) |
|---|---|
| Class 00 | 500 V |
| Class 0 | 1,000 V |
| Class 1 | 7,500 V |
| Class 2 | 17,000 V |
| Class 3 | 26,500 V |
| Class 4 | 36,000 V |
In Indian practice gloves are often named by the system they suit, an 11 kV glove (a Class 2 glove, rated to 17 kV) or a 33 kV glove (a Class 4 glove, rated to 36 kV). Every pair is dielectric-tested at manufacture and carries a proof-test record.
Match the glove to the voltage of the job
The class rating is a ceiling: the glove must be rated for the voltage of the job, or higher. An 11 kV glove is the right tool on an 11 kV system, but it is not rated for 33 kV, so on a 33 kV job the margin it was certified for simply isn't there. The two look almost identical in the hand, which is exactly why a wrong-rated pair can reach the wrong job without anyone noticing.
Our rule: ISI-marked, 33 kV, every job
Rather than leave that to selection on the day, Shreetuvis holds a standing rule: the rubber gloves that go to any electrical job are ISI-marked and 33 kV (Class 4) rated, full stop. Standardising on the highest common rating means the gloves on site are always rated at or above the voltage being worked on, never below, and the selection error is removed at the source. The ISI mark is the assurance the glove was made and tested to IS 4770, the same logic as any other certified product (see the ISI mark).
A glove protects only while it's sound
A rating on the cuff holds only if the glove itself is intact, so the discipline runs past the purchase:
- Inspect before every use, a visual check plus an air (inflation) test to catch pinholes or cracks.
- Re-test periodically, the standards call for a dielectric re-test at regular intervals (IEC 60903 sets a maximum of six months), including for gloves that have only been in storage.
- Store them properly, flat, away from heat, sunlight, ozone and sharp tools, in their protective packaging.
- Retire a damaged pair, any cut, puncture or chemical contact takes a glove out of service, whatever its test date.
The right rating, an intact glove, checked before it is worn, simple discipline, done every time. It sits alongside the rest of how we run site work, covered in good wiring workmanship.