I am not an electrican so please forgive me if I incorrectly identify anything discribed in my question. I have a condo in a high rise building that was constructed in the early 80's. All of the wiring is two wire BX or AC flex cable with no ground wire. The circuit panel is supplied with two hots and a neutral, no main disconnect, and no ground bus. If I were to add a new circuit to the panel (using AC flex cable with two wires plus ground), how would I properly attach the ground wire to the circuit panel. Thanks in advance
No ground bus in panel
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i'm going to say add a ground bar, put lets see what other recommendations appear
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put bare wire same as others
The sheathing of the bx and ac is the ground. The riser for the panel is more than likey rigid pipe, which goes down to the meter room. This where your meter and disconnect is located. Everything is bonded together by the pipe. This why there is no ground barin your panel.
If you intend to run new circuits using mc cable than a ground bar will have to be installed in the panel.
If you intend to run new circuits using mc cable than a ground bar will have to be installed in the panel.
Thanks for the response. Will the ground bus just be screwed/bolted to the panel? Sounds like a simple fix.
Normally a ground terminal strip (ground bus bar) is screwed to the back of the panel but there may be extra steps in the instructions. At the very least, scrape all of the paint off of the area where the bar will be attached so there is metal to metal contact.
BX cable sheathing is not considered an "adequate" ground. There may or may not be a bare wire or metal strip running through the BX cable to be an adequate ground. If 3 prong receptacles are installed where 2 prong receptacles used to be and you want a true ground where there was none, then you will have to run a separate ground wire from the receptacle to the panel. (The wire need not follow the exact path of the circuit conductors or BX cable.)
BX cable sheathing is not considered an "adequate" ground. There may or may not be a bare wire or metal strip running through the BX cable to be an adequate ground. If 3 prong receptacles are installed where 2 prong receptacles used to be and you want a true ground where there was none, then you will have to run a separate ground wire from the receptacle to the panel. (The wire need not follow the exact path of the circuit conductors or BX cable.)
You can get ground bar kits at most big box stores (Lowe's, Home Depot). But you need to know the brand of your panel - they're not really interchangeable.
For Square D panels (the only ones I'm familiar with), the ground bar does indeed just screw into the back of the panel. The holes are already there. Some panels have spaces for two ground bars.
For Square D panels (the only ones I'm familiar with), the ground bar does indeed just screw into the back of the panel. The holes are already there. Some panels have spaces for two ground bars.
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