I would like to know if there are ways to reduce the incident energy in low voltage switchboard sections beyond the main breaker to other distribution sections.
As an Industrial Contractor, we are asked to perform varies duties including installing feeder breakers in distribution sections of Main switchboards. These feeder sections are somtimes 3 or 4 sections away from the main breaker compartment. These sections are bolted together by buss, side by side with the normal barriers and safeguards in place.
The Arc Flash and Coordination studies have been performed and it is revealed to have an incident energy requiring an Extreme Danger rating. This is based on the line side of the incoming service leads from the Utility Transformer before going through the main overcurrent. Can the subsequent distribution sections be calculated at say a Level 4 PPE level or lower based on the overcurrent calculations from the secondary of the overcurrent device. Or since this switchboard Main compartment is not separate from the other distribution sections and the line side service leads are in the entire enclosure does all sections require the Extreme Danger rating?
This is the difference between calling the utility provider to shutdown power instead of locking out the main breaker and performing a rather routine feeder breaker changeout in a section of switchboard, 3 sections away from the main compartment.
Safety is more important than the time it takes to call the utility provider, but I want to make sure I am clear as to what to tell my customers so their maintenance men know the rules and I am labeling the switchgears properly with the correct PPE and incident levels after all calculations are performed.
As an Industrial Contractor, we are asked to perform varies duties including installing feeder breakers in distribution sections of Main switchboards. These feeder sections are somtimes 3 or 4 sections away from the main breaker compartment. These sections are bolted together by buss, side by side with the normal barriers and safeguards in place.
The Arc Flash and Coordination studies have been performed and it is revealed to have an incident energy requiring an Extreme Danger rating. This is based on the line side of the incoming service leads from the Utility Transformer before going through the main overcurrent. Can the subsequent distribution sections be calculated at say a Level 4 PPE level or lower based on the overcurrent calculations from the secondary of the overcurrent device. Or since this switchboard Main compartment is not separate from the other distribution sections and the line side service leads are in the entire enclosure does all sections require the Extreme Danger rating?
This is the difference between calling the utility provider to shutdown power instead of locking out the main breaker and performing a rather routine feeder breaker changeout in a section of switchboard, 3 sections away from the main compartment.
Safety is more important than the time it takes to call the utility provider, but I want to make sure I am clear as to what to tell my customers so their maintenance men know the rules and I am labeling the switchgears properly with the correct PPE and incident levels after all calculations are performed.
