Ground

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Ron merritt

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Had a customer add a ground bar to an overhead crane,they took the ground wire from the bar and connected it to the building steel and called it good as a ground for the crane.They installed a collector to carry the ground to the bridge panel.
 
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LarryFine said:
Is there a question?
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Ron merritt said:
Had a customer add a ground bar to an overhead crane,they took the ground wire from the bar and connected it to the building steel and called it good as a ground for the crane.They installed a collector to carry the ground to the bridge panel.
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Yes is that an acceptable ground or is that bonding and they still need to carry a egc back to the service panel.
 
I started to write that a crane is not part of the nec but it is. I assume this is a crane that is inside a building. The only mention of grounding is below and then reference are made to part V and VII of article 250.

Part VII. Grounding
610.61 Grounding. All exposed non–current-carrying metal
parts of cranes, monorail hoists, hoists, and accessories, including
pendant controls, shall be bonded either by mechanical
connections or bonding jumpers, where applicable, so that the
entire crane or hoist is a ground-fault current path as required
or permitted by Article 250, Parts V and VII.
Moving parts, other than removable accessories, or attachments
that have metal-to-metal bearing surfaces, shall be
considered to be electrically bonded to each other through
bearing surfaces for grounding purposes. The trolley frame
and bridge frame shall not be considered as electrically grounded
through the bridge and trolley wheels and its respective
tracks. A separate bonding conductor shall be provided.
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3 phase overhead crane feed with runway bars and picked up by collectors on bridge to supply crane.Recently added forth bar to ground the crane,instead of running back to the service panel they connected that bar to the building steel to ground the crane.
 
Ron merritt said:
3 phase overhead crane feed with runway bars and picked up by collectors on bridge to supply crane.Recently added forth bar to ground the crane,instead of running back to the service panel they connected that bar to the building steel to ground the crane.
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Nec covers overhead cranes I was looking at 610.61
 
Yes I mentioned 610.61 above. I don't see any issue with bonding to the building steel as long as the steel is bonded back to the service
 
My question is ,is the building steel an acceptable ground for the system by itself or do we need to carry an egc back to the sevice panel
 
If there is no equipment grounding conductor with the 3 phase conductor then yes, I believe an equipment grounding conductor is necessary to be run with the conductors.

300.3(B) Conductors of the Same Circuit. All conductors of the
same circuit and, where used, the grounded conductor and all
equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary gutter,
cable tray, cablebus assembly, trench, cable, or cord, unless
otherwise permitted in accordance with 300.3(B)(1)through
(B)(4)
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