For the reasons given in my first response, for engineering purposes, I see two indentical numbers, just with different no. Chapter 82 provides additional requirements, measures and recommendations for design, erection and verification of all types of low voltage electrical installations. A common example is RCDs with residual current rating not exceeding 30 mA in a caravan, required by Regulation 721. However, this is not the case as the product standard BS EN 61008 requires a half wave pulsating residual current of 0.

Finally, remember an RCD has a finite lifespan, so, give consideration to whether or not extensive testing is beneficial or may have the opposite effect.Since the First Edition of IET Guidance Note 3 Inspection and Testing, the guidance has been that, for both Step 2 and Step 3 of the test for continuity of ring final circuit conductors, the readings at each point on the circuit will be substantially the same, disregarding parallel paths. There is no longer a requirement to perform a test using a test current equal to or higher than five times the rated residual current. All electrical installations will require inspection and testing at periodic intervals as they will deteriorate with age, use, possible damage and any additions or alterations by non-competent persons.

Regulation 16 of the Electricity at Work Regulations 1989 requires persons carrying out electrical work to be competent. What is important for the person carrying out the inspection and testing is the predicted reading of the instrument, which is usually shown to two decimal places. Given the prevalence of electronic equipment in most installations, it is difficult to see how the electrical designer will be able to justify the use of Type AC RCDs. When the instrument setting selected is for an AC Type RCD, the test current applied is a 50 Hz alternating current. of BS 7671:2018 requires continuity of protective bonding conductors to be verified by measurement of resistance.Subsequent intervals will be recommended by the competent person carrying out the inspection and testing. In the sense that one is not re-print of the other, they are not the same, however, for the example you highlight the difference is 0.