2004年7月9日 · Help needed in sizing equipment grounding conductor when cable are installed in parallel, in cable tray. Setup: Ambient Temp Max. 30C Seconday Unit-Substation Pri OCPD: 4,160V Fused Switch, 300E Fuse XF Pri Feeder: 3/C-250kcmil w/ #3 Gnd, MV-90 XF: 1500kVA, 480Y/277V, 5.75%, Dry XF Sec Feeder...

2007年10月1日 · Help needed in sizing equipment grounding conductor when cable are installed in parallel, in cable tray. Setup: Ambient Temp Max. 30C Seconday Unit-Substation P EGC Sizing / Parallel Sets - Electric power & transmission & distribution - Eng-Tips

2006年10月10日 · The underlying logic of the EGC sizing is to provide sufficient ground fault current back overcurrent device to allow it to operate before the EGC is damaged. As a practical matter, I would be concerned about the ground pickup being changed in the future by someone who doesn't know what the ground wire size is.

2007年5月16日 · Hello, I am working with an Eaton SPX 300 Hp drive. The drive manual recommends that for incoming power cables, phase conductors should be 2 @ 300 kcmil, and the ground conductor should be 1 @ 300 kcmil. The question I have is about the ground. The upstream breaker is 500A. According to NEC...

2002年2月12日 · It appears that the transformer is on the dock. The conductors from shore to the xfmr are primary conductors and the #1 ground conductor in there are the equipment grounding conductors (EGC) for the primary circuit. Hopefully it is sized correctly as primary EGC and bonded to the xfmr frame.

2015年6月22日 · Are these conduits installed above ground for their entire length (ie no underground portion). I am not sure of what the NEC says wrt U/G conduits, but in Canada (eh) the conduit cannot be used as an EGC if the conduit is installed U/G. GG "I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

2020年7月11日 · NEC often results in more than two gauges in EGC size reduction- up to 10-12.5% of the phase conductors, so breaker clearing time would really matter. The thing is you're right- assuming phase and EGC are the same size it is technically 50/50 relative to remote earth. But the 92 volt number has me confused.

2017年7月11日 · None of them have equipment grounding conductors (EGC's) installed. While using the conduit as an EGC is legal per code, in almost all of our installations we do not do it; however, in this instance it might be necessary. We can't find any sizing requirements for the conduit to be used in this way.

2003年7月6日 · Has there been any publication for loop impedance calculations under NEC environment, identical to IEC or BS 7671? The table 250.122 in NEC provides the minimum EGC size for particular breaker. Is this size linked with loop impedance? Over and above voltage drop, do we need to establish loop impedance criteria and determine limiting cable lengths?

2006年7月14日 · Further I still have to run a EGC now to the new panel. However I am really running two ground conductors that are tied together at the generator, but ran to two different location. I was wondering if there was a better solution like running only a GEC to the first panel and then split it out for the GEC and then a EGC.