How is service panel and conduit system connected to electrode ground?

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donboy

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Hello folks, newbie here.

I have an old Bryant B20-20FM panel. Here are salient facts about the installation:

1. The ground electrode comes from the street-side water pipe as a copper wire coming through a flexible metal conduit. This conduit attaches to the panel bottom wall and the copper wire comes through and terminates on a common neutral-ground bar.

2. The panel does not output any ground wires but only hot and neutral wires.

3. The neutral-ground bar does not appear to be bridged to the service panel enclosure, but I measure zero ohms between the bar and the enclosure.

4. Throughout the house ground conductors are derived from the metal conduit system. So the EGC path is intended to be the metal conduit system.

My question: Given the apparent lack of any visible connection of the neutral-ground bar to the panel enclosure, how does the metal conduit system/panel enclosure get connectivity with the neutral-ground bar? What is the typical/intended installtion to achieve that? Just trying to ensure everything is kosher in this old house and to understand things theoretically.

Thank you.
 
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Thank you guys. I do not see any screws going into the enclosure through the neutral-ground bar. And there is no lug jumper that I can see. I will take a photo and post it shortly.
 
donboy said:
Hello folks, newbie here.

I have an old Bryant B20-20FM panel. Here are salient facts about the installation:

1. The ground electrode comes from the street-side water pipe as a copper wire coming through a flexible metal conduit. This conduit attaches to the panel bottom wall and the copper wire comes through and terminates on a common neutral-ground bar.

2. The panel does not output any ground wires but only hot and neutral wires.

3. The neutral-ground bar does not appear to be bridged to the service panel enclosure, but I measure zero ohms between the bar and the enclosure.

4. Throughout the house ground conductors are derived from the metal conduit system. So the EGC path is intended to be the metal conduit system.

My question: Given the apparent lack of any visible connection of the neutral-ground bar to the panel enclosure, how does the metal conduit system/panel enclosure get connectivity with the neutral-ground bar? What is the typical/intended installtion to achieve that? Just trying to ensure everything is kosher in this old house and to understand things theoretically.

Thank you.
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Is that a bare CU? If so, it is making a bond at least via the FMC.
The Neutral would also be bonded at the POCO meter socket enclosure, which would give you a bond via the metallic raceway between it and your panel.
 
Thank you. Yes, it is bare copper in the FMC. Rather than post a bunch of big pictures, let me further ask first:

1. A copper wire snaking through FMC seems a bit shaky for a good bond. Is it adequate?

2. Assuming the POCO bonding is there is that adequate?

3. Should I stop worrying about it or should I have an electrician install a bonding jumper in the service panel?
 
donboy said:
Thank you. Yes, it is bare copper in the FMC. Rather than post a bunch of big pictures, let me further ask first:

1. A copper wire snaking through FMC seems a bit shaky for a good bond. Is it adequate? No.

2. Assuming the POCO bonding is there is that adequate? It is required to be bonded in the Service Entrance Panel as well.

3. Should I stop worrying about it or should I have an electrician install a bonding jumper in the service panel?
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Do you have a disconnect on the exterior of the home?
Post the picture. Someone here should be able to tell you if it is missing.
 
OK, thank you, I'll get some pictures tomorrow after the snowstorm stops. :)

I guess I'm only concerned that the conduit system is taking a serpentine path to reach the electrode and neutral-ground bar, but maybe it's inconsequential as it isn't current carrying.
 
Ah, thank you for that. The conduit system, then, is apparently reaching the neutral at the meter with a fairly direct path, assuming the bonding jumper is there. I read somewhere that the bonding is done in the factory so it's highly unlikely it is missing. But I will try to check it tomorrow, weather permitting.
 
What is the conduit type for the house circuits? FMC has limitations on grounding. Old AC cable is no good, but the newer type with the metal tape under the armor is ok. You may have more grounding issues than you realize...
 
The main conduit throughout the house is solid metallic. It's only the electrode connection from the water pipe that is in FMC. I don't know right now about meter to panel. I will check that tomorrow. Thank you for your reply. I greatly appreciate all the replies from the experts here!
 
Folks, there is a disconnect at the meter and the conduit from the meter case to the breaker panel is solid metal conduit. My understanding is that the bonding is done there and that the breaker box is secondary and should not have neutral connected to the case there. So I think everything is kosher, assuming it is OK to land the electrode on the panel neutral bar. Thank you all very much for your assistance!
 
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Not sure about Cook County as a whole, but the Schaumburg code requires solid metal conduit, with the exception that short runs (6 feet or less) can use FMC as whips to devices (such as hard-wired dishwashers). Also, PVC conduit is allowed as long as there is a ground return conductor included in the conduit that is properly bonded at both ends. However, there is no PVC in my house. I have found an FMC run to a ceiling fan >6 feet installed by a previous owner. I will have that replaced by an electrician.
 
ptonsparky said:
Is Cook County the only 'all conduit' in the State?
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I think that there are suburbs outside of Cook County that do not permit cable wiring methods.

Our small town in LaSalle County permits cable wiring methods for dwelling units up to 5 in a structure. If you have 6 or more dwelling units in a structure or you are doing commercial work, we don't permit cable wiring methods.
 
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