Rubber personnel protective insulating equipment must be marked with the appropriate voltage rating and:

• A. Expiration date
• B. Issue date
• C. Serial number
• D. Manufacture name

Answer: (A)

The important idea is that insulating rubber equipment ages and can lose its dielectric strength over time, so it must carry a date that indicates when its usable life ends. The voltage rating shows the maximum electrical voltage it can safely withstand, but rubber insulation degrades with heat, ozone, and wear, even if there’s no visible damage. The expiration date tells you when the manufacturer recommends retiring the item or re-testing it, ensuring you don’t rely on insulation past its guaranteed life. marks like the issue date, serial number, or manufacture name help with tracking and identification, but they don’t convey the remaining safe service life, which is why the expiration date is the necessary additional marking.