BS 419 covers fabrics woven from cotton, silk, nylon polyethylene-terephthalate (PTP)5) and glass, coated on both sides with varnish, and of nominal thickness from 4 mil (0.10 mm) to 10 mil (0.25 mm) supplied in the full width of approximately 36 inches (915 mm) or slit into tape. Although the types of varnished fabric are described throughout BS 419 as “yellow” and “black”, any varnish having the appropriate properties but differing in colour may be used, by agreement between the purchaser and the supplier.
BS 419 on varnished fabrics and tapes is useful for:
Varnished fabric and tapes are used for providing insulation at joints and terminations. It is important for a designer and manufacturer to select insulation of varnished fabrics and tapers appropriately for the their use otherwise may cause system failure, and short circuits.
BS 419 provides best practice guidelines for manufacturers and even the users for obliging to agreements.
BS 419 provides specifications such as:
Using these specification mentioned in BS 419 can help you with selection and inspection process to make electrical systems safer and reliable.