I work as a commercial meterman for an electric utility. We use Salisbury class 0 rubber gloves with leather protectors for all low voltage work (under 600v) and use class 2 rubber gloves with leather protectors and rubber sleeves for all primary work (performed from a bucket). The gloves provide necessary electrical protection, but need to be tested on a regular basis. We send our gloves out monthly for testing, to a testing lab. On an annual basis, approx 20 - 25% of our gloves, fail the testing either due to electrical failure or deterioration.
I strongly recommend anyone using rubber gloves for electrical safety, adopt a glove testing program.
Bob