Is a house without a service ground wire to the panel safe?

Question

My house is served by a direct bury underground supply consisting of two hots and a neutral. There is no ground associated with that service wire. Is my house safe wired that way? I guess they used to do that prior to 2008. The only ground I have is a ground rod and associated wire that connects to the equipment grounding lug in what I guess would be considered a subpanel in the house. There is no real easy way to get a ground wire from the disconnect at the pole to the house without tearing a bunch of concrete up, or running an overhead ground to the house, and that is not a very practical method. Just wanting to know if my house is safe, and if not, in what circumstances is it unsafe, and what should I do?

Answer 1

I just had my service upgraded from 100A to 200A a couple of months ago. This is exactly what the power company's contractors ran from the pole through the bore to my new meter/main panel.

Your house is wired like all the other houses in the US.

If you're not in the US, please edit your question to indicate that, as things may be different in other countries.

Answer 2

The power company usually does not run a ground line. they run two hots and a neutral that will be tied to a ground at the pole or transformer. Once you get the service from the power company, you have ground rods installed or utilize water pipes that will be connected to the grounding lug in your panel. Depending on the type of panel, your neutral could be connected to the ground wire or be isolated from it.

Answer 3

In standard US residential wiring, the utility supplies hot/hot/neutral and not ground. The usual setup is one of two possibilities:

• Overhead service feed (hot/hot/neutral) to meter at the building
• Underground service feed (hot/hot/neutral) to meter at the building

In both cases, the utility controls the wires up to and including the meter and your part is after the meter.

The ground is added at the first connection after the meter. That can be:

• A disconnect switch
• A meter main - a single box that includes a socket for the meter and a small breaker panel (i.e., usually small in number of spaces, but large in capacity - 100A or more)
• A main panel - either next to the meter or, typically, a few feet away on the other side of a wall (so that the main panel is indoors even though the meter is outdoors).

In all of these cases, there is a single neutral/ground bond in that first location after the meter. This is also the location where a ground wire starts that goes to one or more ground rods and/or a water pipe.

The ground provides two key functions:

• A return route for regular power in certain appliance and wire failures - i.e., power goes out on hot and back on ground (instead of neutral) and is able to trip a breaker. For this purpose, the utility is not involved as the goal is to trip a breaker in your panel.
• A return route for "natural" electricity, such as lightning. For this purpose, the utility is not involved as the goal is to get the electricity out to the ground rod(s) and/or water pipe to get it to the actual ground (dirt).

So there is no need for ground to go back to the utility, and therefore the utility doesn't supply the ground wire.

Answer 4

I think the other answers have covered why there is no ground wire from your electrical service provider, but a converse question is worth fleshing out: What makes electricians run a grounding rod at all?

The simple answer is that most jurisdictions will tell you to follow National Electric Code (NEC) regulations. All modern NEC codes require a grounding rod on your main panel

The requirements for grounding and bonding begin at the service. The NEC requires the neutral(s) to be routed with the ungrounded conductors (hots) to the service entrance equipment and it shall connect to the neutral(s) terminal or bus. The neutral service conductor is required to be connected to a grounding electrode conductor (line to ground rods) at each service. The main bonding jumper shall connect the neutral to equipment-grounding conductors (ground wires) and the service entrance enclosure via the neutral’s terminal or bus.

And

The minimum sizes of the neutral, EGC and GEC are determined based on NEC Table 250.102(C)(1), Table 250.122 and Table 250.66, respectively. The sizes for the main bonding jumpers, supply side bonding jumpers and system bonding jumpers can also be sized from Table 250.102(C)(1).

Why did the electrical company get away with this?

The electrical company likely sent a lineman out when the house was built. The only things they are going to do is make sure there's a spot for the meter. The utility itself might have some other minor "insurance/state regulations make us do this" spot-checking, but it's not their problem, generally speaking. They're almost certainly not a licensed electrician, and I've never seen a lineman do an inspection (although it's possible some areas do require one done separately before hookup). They hook their wires to their side of the meter connection, slap a meter in, and flip the switch. Whatever happens beyond the meter is up to you.

If you're in a city (or county) jurisdiction, the city almost certainly has some sort of licensing scheme where you have to have some sort of inspection upon adding or repairing electrical service. If the inspector comes out and finds your ungrounded panel, they usually have the authority to shut the power off and/or fine you (and your little electrician too!). If you don't live inside a jurisdiction that forces you to have an inspection (i.e. you live in a remote area), it's fully up to the electrician to comply. Without an inspection, there's typically nothing the local government can do before-hand (if an electrical fire burns your house down, that might draw their attention, however).