Detail
Article 19.10(9) - Control of insulation resistances
According to Article 19.10(9) insulation resistances and the earthing of electrical systems shall be checked during additional inspections.
Question:
what should be the scope of these checks? Which components / electric circuits are to be checked?
Answer / proposed solution:
Generally speaking, all electric circuits and cables are checked when they first enter service.
In the event of an additional inspection as construed by Article 2.09, it is difficult to check all the circuits and electrical cables as the latter may be inaccessible because of their configuration or location and because of the risk of damage to equipment being supplied with power. Also, measuring all the electrical circuits and cables would be extremely tedious work.
The electric circuits and cables to be checked come what may should therefore be defined (for example, the switchboard distribution circuits, the power cables required for the proper functioning of the systems affecting the vessel’s safety, etc).
To carry out measurements onboard, it is important to be able to match the electric circuits with the equipment they supply to avoid damage. To this end, the documents on the system to be checked are to be updated and made available to the expert.
Operating checks should also be carried out on differential circuit breaker threshold and activation time.
Loop controls should also be included in the measurements to ascertain whether the protection unit (fuse) is able to cut the power supply in the event of an overload.
Individual recorded values should appear in a report.
Solution:
it could be helpful to adapt Chapter 9 of the RVIR (Chapter 10 of ES-TRIN) with a reference to these new provisions in Article 19.10(9).
RV/G (07) 71
Currently, the requirement only calls for the insulation resistance to be checked; specific measurements intended to identify defective parts are not necessary.
RV/G (07) 90
CCNR Inspection Regulations Working Group RV/G, insulating resistances, electrical systems, controls
