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We just bought a house. It was built around 1960 and it looks like it has not been re-wired. The panel was possibly updated, but it still looks pretty old and I don't see any ground bar in it. Here is a picture of it:



I know that *some* of the outlets seem to be grounded (ground test on outlet passes), but some of outlets are not grounded. So, I assume there is some sort of grounding done, although I do not see it in the panel.

The main service entrance has a different panel on the outside wall of the house. The meter is also located in that panel. That main panel has a two circuit breakers, one for 100 Amp (main house), another for 50 Amp (AC).

So, it looks like the electrical panel in the house is sort of a sub-panel. It want to replace it with a new panel and use AFCI breakers wherever needed (based of NEC 2008). I also want to add a 60 Amp sub-panel to garage that is connected to this panel in the house.

My questions:

(1) Where is the grounding? How can I test that the panel box itself is grounded? When I replace the panel, what will I do with the ground bar? (I might eventually end up a new re-wiring project). Should I add new ground rods and connect the new panel to those?

(2) I see that some of the neutral wires were shared. Is this acceptable? Two hot wires go to different breakers, but they share a neutral wire.
 

· Licensed Electrician
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If this sub is piped with metal conduit, which it appears to be, then that conduit is the ground path. Nothing would be needed to be done code wise. You may want to Google FPE and house fires tho.
 

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We just bought a house. It was built around 1960 and it looks like it has not been re-wired. The panel was possibly updated, but it still looks pretty old and I don't see any ground bar in it.
Not all panels need a separate ground bar. Main panels use the neutral bar(s) for both neutrals and equipment grounds.
This sub-panel may not have needed a separate ground bar. Maybe the circuit cables did not have a grounding conductor. Maybe they used AC cable. Maybe things are in pipe.



I know that *some* of the outlets seem to be grounded (ground test on outlet passes), but some of outlets are not grounded. So, I assume there is some sort of grounding done, although I do not see it in the panel.
Equipment grounding can come from several different sources. It is not always a bare copper wire.





So, it looks like the electrical panel in the house is sort of a sub-panel.
It IS a sub-panel




(1) Where is the grounding? How can I test that the panel box itself is grounded? When I replace the panel, what will I do with the ground bar? (I might eventually end up a new re-wiring project). Should I add new ground rods and connect the new panel to those?
It may have an equipment ground, it may not. This cold be a pipe that the feeders were run in. Testing for it is is not nearly an exact science. It is more of a visual check. If there is an equipment ground path then you would just screw a ground bar to the panel box.
Grounding electrodes have NOTHING to do with equipment grounding. They originate at the main panel only and serve a very different purpose.




(2) I see that some of the neutral wires were shared. Is this acceptable? Two hot wires go to different breakers, but they share a neutral wire.
Yes, this is very typical and perfectly fine.
 
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