Hello everyone. I have come across this so many times I’m starting to doubt myself. This is a subpanel serving the branch wiring for a condo. The main service disconnect is below the meter box. Here you see the ground bus mounted to the enclosure and ground screws present. Is it not so that grounds and neutrals are to be separate and elevated from the enclosure anywhere downstream from service disconnect? I see it this way on almost every other panel I inspect . Surely this many electricians cannot be mistaken. Sometimes it’s only the ground screws present and the bus bar is floating. It is a 4 wire feed from the service disconnect. Thanks for the help.
The set up in these pictures looks okay to me unless those are bonding screws at the top of the neutral bus bars
Those don’t appear like enclosure bonding screws from here. The neutral bus appears to float, as it should. They just bond the neutral busbars to the grounded conductor via the bonding bar they screw into.
If no bonding screw on the neutral busses, it looks like you are good to go, Andrew.
Grounds, grounded conductors (aka neutral), and their respective terminal strips do not and should NOT ever float. This is one of the common misconceptions shared by too many home inspectors. The grounded and grounding conductors in a residential electrical service are always solidly grounded.
Forgive me if I wasn’t clear. From remote distribution panel’s prospective the neutral bus is floating or isn’t bonded second time, creating parallel paths. It is understood that it is bonded at the service equipment and thus bonded to the grounding system in broader sense. Would be a tad difficult to clear a ground-fault if they weren’t. Hope we’re on the same page, now
Yes the neutral is floating with respect to the metal enclosure which it is not directly connected to at the remote panel.
Perhaps the misunderstanding that arises is because of the use of the word “float.” In electrical usage that term has a common usage that is often misapplied. The neutral connection on the secondary of an isolation transformer can be said to “Float” because it is deliberately kept aloof from any connection to earth/ground as well as any other surface the transformer enclosure may be in contact with. One common use for isolation transformers is to power double insulated tools used in ship building or scrapping. All Grounded Carrying Conductors (Neutrals) should be kept free of any connection to Ground until they are all the way back to the Service Equipment’s Main Bonding Jumper. That is needed to keep current from flowing on the exposed conductive surfaces of the premises wiring system so that the voltage drop of the pathway back to the Service Equipment; especially in the event of a high impedance or open connection in the neutral conductors, will not elevate the touch potential of those surfaces to dangerous voltages. Keeping the neutral of the wiring system free of any connection to ground that is outside of the Service Equipment Enclosure is not the same as floating the neutral.
The neutral connection does NOT ever, under any circumstances float. Not ever! The center tap is ALWAYS solidly grounded.
No Robert. I’m sorry but you are wrong. Being disconnected at a particular point does not constitute Floating. Floating has a very specific meaning in the electrical world. Floating means complete electrical isolation.
As I stated it’s floating with respect to the enclosure of the sub-panel or in other words it is isolated at that point which is how many think of it. You’re correct that a solidly grounded system does have the neutral connected to the EGC at some point and it is not completely isolated. I agree that isolated is a better term than floating I should have used the word floating in quotes.