This is a newer, replacement All-in-One type Heat-Pump, Roof mounted. (installed 2015, Home is 1984) The cut-offs/breaker box for the unit is directly mounted to the metal duct that is in turn connected to the unit itself. My question is…Should there also be a ground/bond wire coming directly from the unit into this breaker box or is the bond through the unit and duct sufficient? (There is also breakers for the unit at the main panel.) (hope I uploaded photos correctly)
The unit is not properly grounded for several reasons. The first is because the feeder wiring feeding the panel is fed with LFNC which is non-conductive and required an EGC along with the feeder conductors. It appears as if the EGC is the bare conductor within the LFNC but it is landed on a neutral bar that is isolated from the enclosure because there is no bonding screw connecting it the the metal case.
Secondly the conductors going out to the unit are also in LFNC but there is no EGC even in the raceway.
Thanks, I see this quite often especially in older homes and there is no requirement (or no inspection/don’t care) for new installed equipment. Robert, Appreciate the information.
For installations like these you need to look closely at the raceway, if it’s metallic it may qualify as the EGC. If raceway flexibility is required then it must contain a wire type EGC even if the raceway is listed as an EGC.
I see liquid tight. But that’s a thought.
Next, OP- what are you even thinking about using the metal duct is a bond? Do you want to energize the whole building in the event of a ground fault? The duct system is not bonded.
Point taken, I actually explained in my report that this is a real possibility (Danger) to my client. Especially since the bond wire(?) from the feeder is actually not bonding anything since it is isolated to only the neutral buss without a jumper to the box (I did not notice that till Robert pointed that out). so the path of least resistance might just be the metal ducting…all the way to someone changing the air filter on an aluminum ladder.
Thanks for the replies.
Larry
Go for it…
It would be a ground wire, not a bond wire. Different purpose.
A bond ensures that any difference of potential is eliminated. The ground is to ensure a breaker trips.