ECN Forum Forums Code Related Discussion NEC & other Code issues Panelboard Bonding and 517.14

Greg:

HCF is one that 'the book' has to be available! Yes, there is a lot of reading. The Plan Review for most HCF here (NJ) is done by DCA, which I feel is a blessing for me.

We will be running the #10 insulated bonding conductor in 3/8 flex for physical protection since it has to go over 150 feet through ceilings and walls. We will use 3/8 flex fittings to enter each enclosure. Anyone see anything I might be missing?

Time to show my Ignorance of HCF Design Protocols...

Let's see if I have the concept of Section 517.14 correct:

The Specified Redundant Grounding Conductor is Installed, so as to Bond all the Panelboards in the same Individual Patient Care Vicinity, and therefore create an Equipotential Plane - where the Potential (Voltage) between any Two Panelboards in this Identified Vicinity will be Theoretically Zero.

The Potential (Voltage) between Equipment / ECG, and "Ground" (Ground being anything from the Floor directly beneath the Panelboard, to the Earthen areas of which the Building's Foundations have been cast in) is of no Relevance in this Design constraint; only the Potential Difference between any Panelboards supplying Branch Circuitry to the same Individual Patient Care Vicinity.

If the above is correct, the Specific Bonding Conductor (and Design constraints for it), is very much similar to the concepts of Swimming Pool Bonding...
i.e.:

----------------------------------------------------------
Within the Bonded Equipment Plane (Swimming Pool, Water in the Pool, The Concrete Decking surrounding the Pool, and the Mechanical Equipment serving the Pool), if someone was to drop an Extension Cord in the Pool's Water (Cord is connected to a 120VAC Source), Persons entering or exiting the Pool will not experience a Shock, as the Plane is of one singular Potential (120V).
-----------------------------------------------------------

Not being involved with the Design Protocols of Health Care Facilities, I am very curious to the ways and Technical aspects of these Projects.

Thanks to all who participated in this Thread!

-- Scott

BigB:

JUST A HEADS UP:

You may want to check if the flex connectors you are using are UL for grounding/bonding the flex jacket to the enclosures. Some interpert any grounding/bonding conductors installed in metalic raceway, to require the raceway to be bonded, using listed/labeled connectors.

Thanks, that was one thing I was thinking about. I have the screw in type that screws inside the flex and I have some 90s, but I do not know the listing status. The 90s are Arlington, not sure about the straights.

In such a situation the fear is that the bonding conductor can be 'choked' -- thus leaving a voltage potential if even for only a millisecond -- something that can kill a person who is hooked into the equipotential plane via every manner of conductive gear.

The normal resistance to voltage we have is entirely lost when our saline blood is penetrated by various conductors.