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 Post subject: Table 130.7 Parameters
PostPosted: Fri Jan 10, 2014 12:18 pm 
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Joined: Wed Mar 13, 2013 9:12 am
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There are parameters listed to use the tables for PPE determination. Are these parameters for at that specific piece of equipment? For example, I want to remove a panel cover on a 240V panelboard to perform infrared. The parameters are max 25kA fault current and 0.03 sec clearing time, so is that at that panel or is that at the main service breaker?

Do I need to know the fault current and clearing time at each piece of equipment?

Help, I am confused.


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PostPosted: Fri Jan 10, 2014 3:31 pm 
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Polar wrote:
Do I need to know the fault current and clearing time at each piece of equipment?

Yes, that's what the parameters mean. For each piece of equipment.


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PostPosted: Sun Jan 12, 2014 6:25 am 
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The parameters are the worst case assumptions. The table is not valid if your clearing time or short circuit current exceed those values. This often means you have to do a complete study where you can just use IEEE 1584 anyway so the tables are of limited value to cases where almost nothing is known and they are better than nothing.


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PostPosted: Mon Jan 13, 2014 8:38 am 
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The table values should not be considered as worse case unless you can insure that the fault clearing time is met. The hazards can far exceed the values in the table and thus the tables are inappropriate to use for selecting PPE. There is no way that you can be assured of minimum protection using the table.


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