I can tell you from a firefighters perspective how useful dry chemical extinguishers are in combating electrical fires in vehicles- not particularly. You are better off disconnecting the battery first then use foam or water. We never use dry chem on vehicle fires.In some countries, well at least in my country, a fire extinguisher is obligatory by law. I think they should cancel this law for four reasons:
- cars are much safer than in the past concerning possible fires (I don't pretend it never happens).
- most people never check the sticker with the validity date.
- the quantity of powder is so small, that it is often empty before the fire is extinguished
- most people don't know how to use it