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Joined: Dec 2004
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Walked into a plant this afternoon, to quote some work, and I am still noticing guys installing CNC machines, lathes, and such with ground rods by the machines.
I know manufacturers "require" this but the NEC is still somewhat unclear.
Under some excemptions you can put a ground rod if you want but the EGC from the feeder must be tied to it. You can't connect the ground rod by itself to the equipment without that being tied to the service ground.
See where i am going, I hope...
I remove them when I find them, after checking that an EGC was installed.
Am I on the right track?
Dnk.....
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Joined: Nov 2000
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As long as there is an EGC run with the power conductors and connected to the equipment there is no reason to remove the rods. They do not have any adverse effect.
Don
Don(resqcapt19)
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If the machine is properly grounded by an equipment ground run with or enclosing the conductors to the machine, then I see no reason to remove the supplementary electrode.
If the rod is required by the installation instructions furnished by the manufacturer of listed equipment, then it is part of the listing and labeling and should remain in place.
Tom
Few things are harder to put up with than the annoyance of a good example.
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As long as the equipment is grounded to the source as required by the NEC they can add as many 'extra pointless' (supplementary) rods at machine. 250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor. Notice that to the NEC Supplemen tary is entirely different than Supplemen tal
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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Well, 2 things bother me,
One is the obviuos trip hazzard they posses.
Some of them run across the floor 5-6 feet, to where the ground rod was driven.
The second being, in part to how many I have seen wrong. This is where they didn't pull a EGC, and the ground buss bar inside the equipment was tied to the ground rod only.
Dnk...
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Joined: Dec 2000
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This is where they didn't pull a EGC, and the ground buss bar inside the equipment was tied to the ground rod only. Keep in mind that an EGC doesn't necessarily have to be pulled. Conduit also can be considered as the EGC under 250.118. "Wire" is only one of the fourteen acceptable items listed.
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