> Jeff,
>
> Whether multiple ground paths exist is irrelevant. What the
> NEC requires is
> a direct, low-impedance fault return path for each branch circuit,
> considered individually. You cannot dispense with any ground
> paths because
> you think there exists alternate paths. While it is true that parallel
> paths may decrease the total impedance to a fault on any one
> branch circuit,
> that in no way constitutes license to eliminate a required grounding
> connection.
>
> 73, Eric Lemmon WB6FLY
I KNOW! I'm not trying to eliminate the required EGC run along with the
current-carrying conductors. What I'm asking is why you originally said
that you should switch the EGC supplied by the two outlets rather than tying
the two together. I had asked if there were any provisions in NEC that
allowed for EGC's (whether from two different SDS's or otherwise) to ever be
switched, as I can't recall there being any such case allowed in NEC. You
replied that by tying EGC's together that you would create a new path
whereby new, harful currents could flow. I replied that there always exist
multiple EGC paths, whether desired or not, and in the instant case, there
are, or would be, paths between the EGC's of the two systems whether or not
you tied them together.
So, my question remains, is there a case to be made where it is desirable,
or even allowable, that the EGC can or should be switched? Let's assume
that in the instant case (the hospital) that they are SDS's.
--- Jeff WN3A
