Are all materials approved and guaranteed?

Are materials approved by British Standards and does all cabling come under BASEC Why is this important? There have been a lot of reports of substandard materials being used especially cable’s not incorporating the correct amount of copper adequate for the load on the electrical conductor. Using such items could result in risk of electric shock or potential fire hazard. All materials used by Electrical Experts are sourced from approved wholesalers and reputable companies with a minimum of a 12 month guarantee.