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| Short Circuit Current Outside of IEEE 1584 Range - < 600V https://brainfiller.com/arcflashforum/viewtopic.php?f=33&t=4806 |
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| Author: | Jim Phillips (brainfiller) [ Sun Nov 25, 2018 10:04 am ] |
| Post subject: | Short Circuit Current Outside of IEEE 1584 Range - < 600V |
The low voltage (<600V) upper limit of bolted short circuit current for IEEE 1584 goes up to 106,000 Amps. This weeks question: How often has short circuit current gone beyond the upper limit of IEEE 1584 for arc flash studies at low voltage? Never Once 2-5 Times More than 5 Times N/A - Don't perform studies |
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| Author: | PaulEngr [ Tue Nov 27, 2018 9:19 pm ] |
| Post subject: | Re: Short Circuit Current Outside of IEEE 1584 Range - < 600 |
Hard to answer when the quiz doesn't have a selection to pick from. Not sure how to answer this one. I've seen currents show up like this on some studies but invariably they end up based on bad assumptions in the short circuit analysis (or lack thereof). Such as when someone looks at their fuse rating of 200 kA and gives this as a short circuit value. |
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| Author: | graceyj20 [ Wed Dec 19, 2018 10:56 am ] |
| Post subject: | Re: Short Circuit Current Outside of IEEE 1584 Range - < 600 |
I've seen it a few times. Most notably on an SKM model where the main SWGR had 108,000A SCC @ 480V. It rated it as Cat 2 PPE. Talked about it with SKM to find out they switch to Annex D.3 open air model when it exceeds 106,000A... nice. Tweaked conductor length to drop SCC to 105,999A and it turned into no safe PPE. Classic example of why an EE/equiv needs to review all SC / arc flash studies. Spoke to Easy power and they're model ignores the limit of 106,000 for calculations that exceed. No good solutions but it seems more reasonable then the SKM approach assuming it's an open air model. |
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