If you have questions or would like some engineering assistance to properly size your cable tray installation please contact us. The second major change for sizing Equipment Grounding Conductors (EGC) in this new 2020 Code cycle is found in Section 250.122(B) Exception. conductors of size 1/0 AWG and larger size 1 AWG and smaller, comprising each phase, polarity, neutral, or grounded circuit conductor, shall be permitted to not be connected in parallel (electrically joined at both ends). Grounding electrodes of pipe or conduit no smaller than trade size and when of. Aluminum, coper-clad aluminum, or copper. Proper cable tray sizing is complicated and often existing cable trays are overloaded per the code. the points of connection of the grounding electrode conductor and the. In the event of a phase-to-ground fault the GEC must be large enough to survive for the power system’s protection to operate and clear the fault. The larger the ungrounded conductors, the larger the GEC. One of the exception is that a 6 is all that is needed to the ground rod. Normally that would be needed for all electrodes but there are some exception. Raceways are included in another section of the code. Sizing the GEC is correlated to the size of the ungrounded (current carrying) conductors. Table 250.66 tells you what size conductor to use for a grounding electrode. It’s important to note that cable trays are mechanical support systems and not raceways. The National Electric Code (NEC) specifies the minimum size for cable tray systems which includes ladder, ventilated trough, ventilated channel, solid bottom and other similar structures. The calculation is based on Table 250.66 which defines the minimum size electrode conductor of alternating-current systems. The Grounding Electrode Conductor is discussed in Article 250 and the sizing of the conductor in 250.66. From what we have read being that you would have multiple disconnecting means you would have to go by 250.64 (D) (1) to size the GEC which tells you to use 250.66 chart. The National Electric Code (NEC) defines the Grounding Electrode Conductor as the conductor used to connect the system ground conductor or the equipment to the ground-electrode or to a point in the grounding electrode system. The local electrician is trying to use 250.66 (A) which states that the GEC only has to be a 6 AWG copper when connected to rods.
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