Ok, not to beat a dead horse back to life, but I have a sub panel bonding question. In the panel photos the grounds and neutrals are separated, but it looks to my like there is no bonding to the panel. Am I missing something? This seems pretty simple and I’m not sure why I’m being paranoid about it.
Sub panels are never to be bonded. only bonded on the main panel.
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It looks like the bonding screw is missing at the bottom of the left bar. That’s typically where the bonding screw is at GE panels.
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I thought the ground was supposed to be bonded to the panel.
The neutral and ground MUST NOT be bonded at a sub-panel. They should only be bonded at the main service panel. If you bond them anywhere other than the main service, the neutral return current now has multiple paths, including though your ground wire.
You should be able to buy a second bar for the sub-panel if it really is meant to be used as a sub-panel. The neutral bar will need to be isolated (it should have plastic insulator separating it from the case). The ground bar should be bonded to the case.
The ground wire from the house must be connected to the sub-panel ground. Since it is a detached building the ground rods are also required by code and should be tied to the sub-panel ground. The ground to the service is the most important because it will provide the low resistance path back to the service in case of a fault.
Christopher, that makes sense. Does it matter that the ground goes straight back to the ground at the main panel? See photo of main.
I agree with Christopher on the missing bonding screw.
The bond screw would tie the neutral to the enclosure. This is feed by 4 wires so the bond screw should not be installed. This is not the service.
The screw is not “missing”. It was purposely removed!
So how is the EGC bonded to the metal enclosure?
Thanks for being on top of it.
In a subpanel, the terminal bar for the grounded conductors (commonly known as the neutral bus) should always be insulated from the enclosure.
ALSO: In a subpanel, the terminal bar for the Equipment Ground (commonly known as a ground bus) should be Bonded (electrically connected) to the enclosure
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The second hole up from the bottom on the left EGC bus is for the ground screw and as everyone has stated it is missing. Simple fix to install a bonding jumper from the bus to the panel cabinet.
The ground bar typically mounts right to the enclosure. The neutral bar would be on plastic to isolate it from the enclosure unless the bond screw is installed.
Not always… In this panel, the neutral and ground bus bars are not connected to each other, and are also both floating. So this one is indeed missing the bonding screw to bond the EGC buss to the metal enclosure, while leaving the neutrals isolated.
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Yes, it should be, this panel is missing the bonding screw. But this panel is also set up to allow the neutrals to “float”, because the two bus bars are not connected to each other like you typically see in a service panel