| Arc Flash Forum https://brainfiller.com/arcflashforum/ |
|
| Unable to protect from thermal damage https://brainfiller.com/arcflashforum/viewtopic.php?f=4&t=5946 |
Page 1 of 1 |
| Author: | jsoar [ Mon Feb 17, 2025 8:59 am ] |
| Post subject: | Unable to protect from thermal damage |
I have been using both Easypower and SKM and I keep getting a warning on the cable rating not being able to protect from thermal damage. Its just confusing because for example if the breaker is 30Amps and the builder used 10 AWG. The cable should be good since 10Awg is rated for 35 Amps. Is there a setting I am missing? |
|
| Author: | mpparent [ Tue Feb 18, 2025 7:19 am ] |
| Post subject: | Re: Unable to protect from thermal damage |
As long as the breaker is sized to protect the cable/wire per NEC or other standard, it is ok. This is for low voltage (<=600V). Typically, cable damage curves are not plotted on TCCs for LV circuits given the prior statement. As far as MV and HV systems: it's a good idea to plot the cable damage curves and seeing how they perform w/ the OCPD since you are dealing w/ a considerable amount of I^2R heating. Mike |
|
| Author: | NeDCE [ Tue Jan 06, 2026 4:00 pm ] |
| Post subject: | Re: Unable to protect from thermal damage |
mpparent wrote: As long as the breaker is sized to protect the cable/wire per NEC or other standard, it is ok. This is for low voltage (<=600V). Typically, cable damage curves are not plotted on TCCs for LV circuits given the prior statement. As far as MV and HV systems: it's a good idea to plot the cable damage curves and seeing how they perform w/ the OCPD since you are dealing w/ a considerable amount of I^2R heating. Mike Mike, do you know why EasyPower does this? Do you know if SKM does the same thing? Conversely, I ran into a situation recently where EasyPower's AutoCoordination feature recommended setting the LT settings on two 250A-300A MCCBs to a current level greater than the wire's rating. One of the instances it included a notification that doing so would exceed the rating of the wire, but the other one did not. I know any auto-features need a human to doublecheck the findings, but programs like EasyPower and SKM are using complicated calculations; it seems bizarre to me that it would get that wrong. |
|
| Page 1 of 1 | All times are UTC - 7 hours |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|