Hi, I’ve got two quotes for installing a HPWC and they differ by about 2.5x. The more expensive quote has included recommendations from the most recent version of electrical standards (AS/NZS 3000.2018). There is a mention on another thread about type B rcds being required for HPWC installs. The type B rcds detect and prevent both DC and AC leakage. The general idea of the rcd is that they protect against a miswiring or malfunction of the HPWC. However, something would have to be very wrong for the DC battery terminals in the car to make a circuit which goes beyond the HPWC. These safety features are nice to have, however, they are arguably not necessary under current regulations. I intend to investigate further, keeping in mind the cost of the overall job, versus the benefit of being compliant with future regulations. Any feedback would be most welcome.