CRANE GROUNDING REQUIREMENTS - 3 BARS AREN'T ENOUGH

 

It is shocking how many improperly grounded crane systems are still in service!

Would you ever consider installing a high voltage piece of equipment that without a proper ground to protect workers from potentially fatal electrical shock?  At CRANE 1, we would never allow it, but every single day our inspectors and technicians encounter an elementary electrical safety issue with cranes and hoists in the field that has been overlooked in prior safety/compliance inspections or knowingly ignored by the designated person responsible for crane safety at the site.  Many incorrectly think that improperly installed crane electrification without a dedicated ground is "OK"  since it is "grounded" to the structure. or that the unsafe installations are somehow "grandfathered" by OSHA.   OSHA requires that the crane or hoist ground be permanent, continuous and effective. 
This misguided thinking absolutely exposes workers using the crane and touching the hook or other conductive parts of the crane or hoist to a potentially fatal shock whenever the improper ground fails due to debris on the runway or any of a number of other causes. We routinely respond to customers saying their crane shocked their worker, only to find that there is no dedicated ground.  Just think that these systems, without a dedicated ground, rely on a permanent, continuous and effective ground through the trolley wheel bearings through the crane structure through the crane wheel bearings and likely a dirty running surface of the runway and then into the runway structure which is not even properly bonded to the building ground.  That's a lot of potential for grounding failures.

OSHA has required that cranes be properly grounded by decades and the NEC provided updated grounding requirements in the 2005 revised edition of ANSI/NFPA 70 National Electric Code within Article 610, Cranes and Hoists, Section 610.61 Grounding.  Within the text of the section, it clearly states: “The trolley frame and bridge frame shall not be considered electrically grounded through the bridge and trolley wheels and its respective tracks. A separate bonding conductor shall be provided.”   The terms “ shall and shall not ” clearly make the use of a dedicated fourth conductor for ground mandatory. It does not matter if the electrification is festoon cable or insulated conductor bar.

 

The Easy Solution:

CRANE 1 Inspectors or Field Service Technicians or Field Consultants can review your existing system and in most cases, we can simply add a fourth bar and additional collectors to your equipment.  Retrofit extension brackets are mad if the electrification bracket is too short to add a fourth bar.  We will connect the ground to your power junction box to an existing bonded ground.  If a proper ground is not present in the junction, the ground will need to be pulled from the disconnect box.

 

CRANE GROUNDING REQUIREMENTS - 3 BARS AREN'T ENOUGH | Crane 1 Services

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