Where's my ground/neutral?

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Old 09-18-18, 07:23 PM
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Where's my ground/neutral?

I was curious where the ground electrode for my house is located, since I can't seem to find one. There is no rod by the meter. THere doesn't seem to be a Ufer ground, or at least there's no connection coming out of the foundation near the main service panel. It's not connected to the water main, which is PVC.

House was built in 2006 and electric service is underground from a pad-mounted transformer across the street. Here's a photo of the panel with the cover off, taken during our home inspection. I am led to believe the bare aluminum cable on the top right is a ground, but in that case where's the neutral? The bare cable goes into the Romex service entrance cable with the two hot legs.

Any ideas what's going on here? This was unquestionably passed by the city electrical inspector when the house was built, and our home inspector clearly didn't think anything of it.

 
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Old 09-18-18, 09:05 PM
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That bare aluminum wire is neutral. This is grounded at the pole (or transformer pad), but you are supposed to have grounding rod at your house as well.
Not having grounding rod at your house was allowed a while back, Not sure when this changed, but I think it would been required in most counties in 2006.

I also don't see ground wire running out to water line. Do you have plastic water line? (PEX or CPVC?) If you have copper water line, you need bond this to ground at the point of entrance to your house.
If you have CSST gas line, your gas line also has to be bonded to ground. It is recommend to do so even if you have steel gas line.
 
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Old 09-19-18, 04:03 AM
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The pic shows the ground ( bare copper) and neutral (white insulation) wires terminated on the same terminal blocks (vertical strips on the outside of the breakers). This is not allowed by code today. If the neutral wire from the utility opens, all devices connected by the bare copper wire are now ungrounded and personnel protection is lost.
 
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Old 09-19-18, 04:08 AM
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At the first panel or whole house disconnect switch in or on the building, if there is no fat wire from the ground bus bar out to qualified grounding electrodes then you do not have a complete grounding electrode system (you could say house electrical ground).

If there is a metal e.g. water pipe exiting the house and running underground for a distance not known to be fewer than ten feet then that is a qualifying grounding electrode, typically with a #4 copper wire from within 5 feet of where the pipe exits the house over to the the panel ground (or ground/neutral if combined) bus bar.

The current code has a #6 copper wire grounding electrode conductor to a pair of 8' ground rods at least 6 feet apart.

Your house may be grandfathered to not have all of the above but for at least several decades you needed at least one ground rod or buried pipe.

The panel is not said to be required to be grounded to gas pipes although the gas pipes need to be grounded to the electrical system. This can be done by running or extending the fat wire for the water pipe or ground rods to the gas plumbing somewhere on the house side of the gas meter. If there is a gas appliance that uses electricity, has an up to date (grounded) branch circuit, and connected to the gas plumbing with rigid pipe then the aforementioned fat bonding jumper is not needed.

(added later) Just noticed you said you have undergrpund electrical sevice. If the conduit from the panel is metal and runs underground for a distance not known to be under ten feet then that is the qualified pipe grounding electrode. It just needs to be installed in the normal approved fashion with the usual fittings and clamps.

If the exiting water pipe is plastic or otherwise not the chosen pipe grounding electrode you should still ground other metal plumbing to the electrical system. Run a bonding jumper from the plumbing to the panel or to an existing grounding electrode conductor.
 

Last edited by AllanJ; 09-19-18 at 04:46 AM.
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Old 09-19-18, 06:21 AM
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Thanks all. I don't know how to multi-quote here, so here are my responses:
  • The water supply pipe is non metallic. In fact, there aren't any metal pipes in the house except the parts that are immediately adjacent to the boiler. Everything else is PVC.
  • We have no gas service - oil heat.
  • What looks like a large bare copper cable on the left is just several Romex bare copper grounding wires zip tied together on the left side of the panel. They separate into their individual Romex sheaths at the top left of the panel and go out to various circuits. I assume the original electrician did that for neatness.
  • I *think* the underground electric service conduit is PVC as well, but I haven't checked. If it is metal, then there's the answer to my question.
  • To the person who said it's not allowed to mix and match neutral and ground connections on the two buses, the buses are bonded together. It's difficult to see the bond wire, but it connects the two between the main breaker and the others.
And to be clear, this is the main service entrance panel (and only panel in the house).
 
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Old 09-19-18, 06:31 AM
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Is there a grounding electrode connected at the meter box?
 
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Old 09-19-18, 06:32 AM
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Originally Posted by Astuff View Post
Is there a grounding electrode connected at the meter box?
Nope. That was the first thing I checked.
 
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Old 09-19-18, 11:46 AM
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It's good you were curious as it appears your system is woefully lacking. Pretty strange as that is the first thing an inspector checks for. Now you'll need to install two ground rods.
 
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Old 09-19-18, 04:25 PM
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beelzebob. The pic shows the ground ( bare copper) and neutral (white insulation) wires terminated on the same terminal blocks (vertical strips on the outside of the breakers).
That is true only when it is sub-panel. In the main panel, ground and neutral can be on the same neutral bus bar. However, neutral cannot be on ground bus bar.
Both bus bars in the picture is neutral bus bar and they are interconnected.
 
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