How to Maintain the Arc Chutes - NT/NW Maintenance Guide

Functions

The arc chutes of the device:

Are mounted on each arc chamber of the breaking unit
Are composed of splitters and filters

The splitters of the arc chutes limit the stress exerted on the installation by:

Helping to extinguish the arc
Absorbing the arc energy under normal electrical operations and electric faults

The filters of the arc chutes filter the pressured gas expelled out of the arc chamber and cool it to a temperature at which it is no longer ionized and is therefore non-conductive.

Degradation Factors

The factors which can cause degradation of the arc chutes are the following:

Frequent switching operations at rated current
Stresses due to high short-circuit currents

Potential Hazards

Performing regular maintenance on the arc chutes can help to avoid the potential hazards and consequences listed in the following table.

Hazard	Consequence
Hazard	Personal injury	Equipment damage
Arc flash	Death or serious injury	–
Insulation resistance of the case too low and impulse voltage	Electric shock	–
High short-circuit current	–	Degradation of the breaking unit

Preventive Action

The following table lists the preventive maintenance procedures to be performed to maintain the arc chutes of the device.

Maintenance program	Preventive action	Procedure
Standard end-user preventive maintenance	Check the condition of the breaking unit.	Breaking Unit NIII_2_1
Standard end-user preventive maintenance	Check mounting of arc chutes and filter cleanliness.	Breaking Unit NIII_2_2

For more information, refer to Preventive Maintenance Programs.