Caseydrive
New member
Recently I took a reading from a ground wire and a neutral wire. (Two wires) and got a voltage reading. I have also gotten an Amp reading on the ground wire going to the water pipe. Is this a problem?
Neutral and Ground
- Thread starter Caseydrive
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al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Welcome to the Forum!
The answer to your question requires looking at the big picture of the Premises Wiring (System) where you took the readings, and to consider the nature of the measurement device you used to get the readings.
The answer to your question requires looking at the big picture of the Premises Wiring (System) where you took the readings, and to consider the nature of the measurement device you used to get the readings.
- The voltage readings, if taken by a digital volt meter, or some other style of meter with a very high input impedance, can show voltages that many times are best thought of as "phantom voltages".
- If the voltage readings came from a D'Arsonval movement (moving needle style) meter, then the location of the voltage measurement point in the Premises Wiring (System) helps to determine whether there is a concern, and the nature of the concern.
- The "Amp reading on the ground wire going to the water pipe" will require considering both the amount of the current, and the type of source (transformer, most likely) and whether other occupancies are also connected, and whether the water pipe is stand alone or part of a municipal system.
brian john
Senior Member
- Location
- Leesburg, VA
1. Neutral to ground voltage is not only common but a necessity by design, assuming there is load on the circuit and the neutral is ONLY grounded at the service or SDS. The neutral and ground (EGC) are common at only one point, with load on the system and depending on the length of the branch circuit, there will be voltage drop on the neutral and there will be a voltage reading between the EGC and neutral. Typically this voltage should be low assuming one minimizes voltage drop with circuit design.
2. If you have a distribution system that shares a common transformer and metallic connections through utility piping (gas or water) the metallic piping will be in parallel with the system neutrals, as the neutrals are bonded to the metallic piping system in more than one place.
3. If you have a neutral that is grounded downstream of the service or SDS you can have current on the water piping system, you have set up a parallel path with the EGC and the neutral (neutral and ground connected in two locations), and you will have current on some or all of all interconnected metallic structures in a facility.
2. If you have a distribution system that shares a common transformer and metallic connections through utility piping (gas or water) the metallic piping will be in parallel with the system neutrals, as the neutrals are bonded to the metallic piping system in more than one place.
3. If you have a neutral that is grounded downstream of the service or SDS you can have current on the water piping system, you have set up a parallel path with the EGC and the neutral (neutral and ground connected in two locations), and you will have current on some or all of all interconnected metallic structures in a facility.
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