Greetings all. I am new here. Please forgive any initial ignorance to norms of these forums. Hopefully I will pick-up quickly. I have searched the forum archives regarding bonding but did not find a specific answer to my question so here goes.
I have been checking electrical codes and diagrams shown in various documents like "Code Check - Electrical." In the section that discusses sub-panels it says that they should have 4 wires (two hot, one ground, and one neutral) and that the neutral and ground must not be bonded together in the sub-panel. It also provides a diagram in the document that shows the neutral going to one buss bar and the ground going to another as the text describes. They aren't connected to each other by any bonding strap BUT they both appear to be screwed into the metal box, which would bond them together. Should the neutral buss bar be screwed into some form of non-conductive material that is then screwed into the box? What am I missing here?
I hope you will be patient with me as I have another question.
I have purchased a property that has and outbuilding. At the main service disconnect for the home on the property amoung all the OCPDs there is a single breaker for a 120V feed for the outbuilding. It connects to a 6 AWG black wire that is bundled with a white 6 AWG and a 10 AWG ground – the ground is not connected at either end. The 6 AWG white wire connects to the neutral buss bar in the main service panel. In the outbuilding the black 6 AWG appears and connects to a small sub-panel with two occupied circuit breakers. I notice that the building has a single grounding electrode that is attached to the ground buss bar in the sub-panel. The white 6 AWG is also connected to the same buss bar as are two neutrals for the little building’s two branch circuits. As it's wired the sub-panel seems to me to be wired like it is receiving a main service feed but instead of from the utility co. it's from the main house. Here's the three questions about this.
1) Is it wired correctly or should the existing ground between the two buildings be connected to the existing grounding bass bar?, and
2) Does the sub-panel require a service disconnect besides the one in the main house?, and
3) Should the out-building’s neutral and ground path’s be isolated?
Thank you for your kind assistance.
