Normal Conditions

The maintenance programme that must be carried out every one, two, or five years on ComPacT NS subassemblies and the level of competence required on the part of service agents are described in the tables of preventive maintenance programs:

At the end of each five year period, the maintenance programme must be systematically repeated.

These maintenance operations apply for normal operating and environment conditions as defined below.

Normal operating and environmental conditions
Temperature	Average annual temperature <25 °C (77 °F) outside the switchboard (Ti*)
Percent load	< 80% of In 24/24 hours
Harmonics	Harmonic current per phase < 30% of In
Relative humidity	< 70%
Corrosive atmosphere	Device installed in environment category 3C1 or 3C2 (IEC 60721-3-3)
Salt environment	No salt mist
Dust	Low level Device installed in a switchboard equipped with filters or a ventilated IP54 enclosure
Vibration	Permanent vibration < 0.2 g (0,007 oz)

Beyond the above limits, the device can suffer accelerated aging that may rapidly result in malfunctions. For this reason, periodic checks must be carried out at shorter time intervals. On the other hand, when special efforts are made to improve the operating and environment conditions, preventive maintenance operations can be carried out less often.