Is there a Code rule that requires grounding bushings with bonding jumpers on feeders to critical care areas in a hospital. The Engineer is requiring us to remove all panelboard cable terminations and install grounding bushings with grounding lugs for properly sized bonding jumpers. I understand there are rules for bonding at Service per NEC 250.92 and I assume any needed bonding jumpers would be sized per Table 250.66. I further understand there are other bonding rules for over 250 volts, and specific bonding rules for 517.14 for normal and essential panelboards, etc., or if spelled out in the Project Specifications, but...at any rate, do you know of any general requirement for such bushings in critical care areas and how would one size the bonding jumper on a feeder on the load size of the service. It would seem logical to size the jumper as an equipment ground per 2005 table 250.122 rather than per table 250.66 for sizing grounding electrode conductors. Thanks for any help you can give. Note, the engineer is also saying the critical care "area" extends all the way back to the service, which i guess is whole other issue.
Critical Care Feeders Grounding Bushing-Bonding Jumpers
- Thread starter collier
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Re: Critical Care Feeders Grounding Bushing-Bonding Jumpers
See 517.13(A) for the requirement that the raceway qualifies as a grounding path. That refers us to 250.118. If you notice, for certain wiring methods like flexible metal conduit, the requirement for a listed grounding fitting is spelled out. For other wiring methods like Rigid metal conduit, nothing is said about terminating in a listed grounding fitting. Make what you will of that.
517.13(B) adds the requirement of a insulated ground wire. This wire is sized per 250.122. I would think all the bonding wires would be sized per 250.122, rather than 250.66 (which is for grounding electrode conductors).
As far as the critical area extending all the way back to the service, 517.13 seems to only apply to the branch circuits. However, mechanical protection of the emergency branch in 517.30(C)(3) is usually considered to go back to the transfer switch and generator.
Steve
See 517.13(A) for the requirement that the raceway qualifies as a grounding path. That refers us to 250.118. If you notice, for certain wiring methods like flexible metal conduit, the requirement for a listed grounding fitting is spelled out. For other wiring methods like Rigid metal conduit, nothing is said about terminating in a listed grounding fitting. Make what you will of that.
517.13(B) adds the requirement of a insulated ground wire. This wire is sized per 250.122. I would think all the bonding wires would be sized per 250.122, rather than 250.66 (which is for grounding electrode conductors).
As far as the critical area extending all the way back to the service, 517.13 seems to only apply to the branch circuits. However, mechanical protection of the emergency branch in 517.30(C)(3) is usually considered to go back to the transfer switch and generator.
Steve
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