Utility Power and Grounding

Status
Not open for further replies.
D

dasarmin

Member
Location
Texas
Due to recent weather events, many lost power in my area. A friend called and described unusual power issues in the house after the utility turned the power back on. I stopped by with a meter and looking inside the breaker panel measured and 120Vac to Ground from one of the two hot lines but only ~20Vac the other. My assumption was that one leg of the incoming 220Vac had been lost, probably at the service pole.
This made me think about the grounding to this house as well as I assume most of our homes. The feed to this particular house was two lines (220Vac) with bare support cable. My question is about this bare support cable and the grounding at the house and breaker panel. I know grounding at the house is provided by ground rods or water pipes, but does this bare support cable from the utility pole also provide a ground reference from the utility?
Once in the house and in the breaker panel this ground and Neutral become one and both are connected to ground rod or water pipe.

Is this scenario accurate?
 
dasarmin said:
I know grounding at the house is provided by ground rods or water pipes, but does this bare support cable from the utility pole also provide a ground reference from the utility?
Click to expand...
As Mr. HV above said, that bare conductor is the service neutral.

Once in the house and in the breaker panel this ground and Neutral become one and both are connected to ground rod or water pipe.

Is this scenario accurate?
Click to expand...
No. The grounding system begins at the service disconnect. On the line (POCO) side, there is no EGC.
 
I believe the utility service neutral (bare support cable) does provide a ground reference of some kind, since it is connected directly to the pole ground rod (where the transformer is located) and to the primary utility neutral, which in turn is connected to many pole grounds on other poles. However, this ground reference is not meant to replace a NEC approved grounding electrode system and would not perform as well in its functions.
 
Status
Not open for further replies.
Top