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Cautionary Notes
By using the Arc Flash Calculator featured in this website, I agree that I have read and understand the following cautionary notes:
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The Arc Flash Calculator is an aid in determining the proper PPE to safeguard an individual from burns that can be sustained from an arc flash incident. |
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The calculator does not take into account the effects of pressure, shrapnel, metal spray, copper vapor or plasma jets resulting from an arc fault. |
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Calculations are based on actual test results of Ferraz Shawmut fuses, which were tested in accordance with methods outlined by the P-IEEE 1584 Committee. The incident energy levels achieved are equal to or lower than those calculated using the fuse equations contained in IEEE 1584. |
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PPE selected from the incident energy shown in the calculator will be adequate for 98% of arc flash incidents. In up to 2% of the incidents, incurable burns may result. This is based on PPE with standard ATPVs of 1.2, 4, 8, 25 and 40. For PPE with other values, use the next lower ATPV rating. PPE must be utilized any time work is performed on or near energized electrical equipment or on equipment that could become energized. PPE must be utilized during lockout/tagout procedure until the voltage testing has been completed, confirming that the equipment has been deenergized. |
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The calculator data is based on 1ΒΌ" electrode spacing, 600V 3-phase ungrounded system with the electrodes located 4" from the rear of a 20" cubic box, open on one side. Incident energy is measured at a working distance of 18". |
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Amp-Trap® fuse data is based on results of tests that were conducted at various fault levels for Ferraz Shawmut A6D, AJT and A4BQ fuses. Actual results could be different for the following reasons:
| 1. |
System voltage |
| 2. |
Short circuit power factor |
| 3. |
Distance from arc |
| 4. |
Enclosure size |
| 5. |
Arc gap |
| 6. |
Electrode orientation |
| 7. |
Conductor size during arc fault initiation |
Fuses below 100 amperes were not tested, since the incident energy measured with the 100 ampere rating is well below 1.2 cal/cm2 from 1.5kA up.
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Minimum reported incident energy is 0.25 cal/cm2, which is the accuracy limit of the test equipment. |
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The values of incident energy from fuse tests that are reported based on bolted fault currents do take into account the difference between bolted fault currents and arcing fault currents. |
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