NEUTRAL CONDUCTOR FROM THE DISTRIBUTION UTILITY

Status
Not open for further replies.

bobby ocampo

Senior Member
What are the acceptable conductors required for the neutral supplied by the distribution utility? Is messenger wire allowed to be the neutral conductor from the utility company?
 

kwired

Electron manager
Location
NE Nebraska
What are the acceptable conductors required for the neutral supplied by the distribution utility? Is messenger wire allowed to be the neutral conductor from the utility company?
That is typical for overhead distribution. Also remember that if those conductors are owned/maintained by the utility they are generally not covered by the NEC.
 

bobby ocampo

Senior Member
Is there a standard on what conductors should be used for the neutral conductor? Will it cause additional consumption for the customer if the neutral conductor used is not of good conductivity?
 

big john

Senior Member
Location
Portland, ME
Is there a standard on what conductors should be used for the neutral conductor?
Yes, it needs to be a wiring method recognized in the NEC; you can't simply string a piece of Home Depot wire rope and decide to pass current through it.

But you're also likely to run into a technical roadblock: Most common triplex is XLPE on an ACSR messenger wire. It's designed to be used exactly as it is installed, however, the NEC doesn't recognize that as a legal wiring method.
...Will it cause additional consumption for the customer if the neutral conductor used is not of good conductivity?
Absolutely, and you also run into a lot of risk terminating it if it's not specifically designed for the connector you're using, which increases the risk that the customer could have an open neutral on a multiwire circuit.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The OP said the conductors in question were supplied by the utility. The NEC does not apply and the customer has no choice. The conductor selection is up to the utility, not the customer.
As far as consumption, as long as the utility is supplying the correct voltage there is no real issue.
 

bobby ocampo

Senior Member
The OP said the conductors in question were supplied by the utility. The NEC does not apply and the customer has no choice. The conductor selection is up to the utility, not the customer.
As far as consumption, as long as the utility is supplying the correct voltage there is no real issue.

Is there a regulation outside of the NEC for Distribution Utility? Is it acceptable for the consumers to pay extra just because the utility uses a conductor that has large losses in the neutral?

If the conductor used by the utility has low conductivity, does it mean that the losses in the cable is being measured by their meter?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Is there a regulation outside of the NEC for Distribution Utility? Is it acceptable for the consumers to pay extra just because the utility uses a conductor that has large losses in the neutral?

If the conductor used by the utility has low conductivity, does it mean that the losses in the cable is being measured by their meter?
As long as the voltage drop is on the POCO side of the meter the customer is not paying for it.
If there is a long undersized cable between the meter and the official service point, one could argue that the customer should at least have the option to pay to have larger wire used. But it usually does not work that way.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Is there a regulation outside of the NEC for Distribution Utility? Is it acceptable for the consumers to pay extra just because the utility uses a conductor that has large losses in the neutral?

If the conductor used by the utility has low conductivity, does it mean that the losses in the cable is being measured by their meter?
The utility is required to provide voltage within in a range set by the state utility commission. If they undersize the wire too much, the supplied voltage would be below the required range and you could file a complaint with the utility commission.
 

bobby ocampo

Senior Member
As long as the voltage drop is on the POCO side of the meter the customer is not paying for it.
If there is a long undersized cable between the meter and the official service point, one could argue that the customer should at least have the option to pay to have larger wire used. But it usually does not work that way.

Based on the meter configuration for single phase, 3-wire, the two hot conductor passes through the current coil of the meter. The potential coil is between the two hot conductors. Any load that is line to neutral(110 volts) will still be measured by the meter or the load loss of the neutral or the grounded service conductor will surely be measured by the meter.

This means that the distribution utility will just use any type of wire because the losses in the wire will be charged to the customer.
 

big john

Senior Member
Location
Portland, ME
Big John you sure are making what is very common practice to be incorrect. :?
Bearing in my mind what others have said in this thread: The NEC has no claim beyond the POA so in many cases it doesn't matter.

But my understanding is that using that cable for private overhead like a feeder drop would technically be incorrect.
 

Iron_Ben

Senior Member
Location
Lancaster, PA
Point of Attachment, in most cases the dividing line between utility ownership and customer. Bobby, can you give an example of the losses being unfairly charged to the customer? Nothing I've seen in this thread so far smells of a problem or the customer being overbilled. As always, I could be wrong.
 

kwired

Electron manager
Location
NE Nebraska
Based on the meter configuration for single phase, 3-wire, the two hot conductor passes through the current coil of the meter. The potential coil is between the two hot conductors. Any load that is line to neutral(110 volts) will still be measured by the meter or the load loss of the neutral or the grounded service conductor will surely be measured by the meter.

This means that the distribution utility will just use any type of wire because the losses in the wire will be charged to the customer.
They don't have to monitor the neutral - what comes in on the ungrounded conductors has to go out on either the other ungrounded (in which case it is measured - and at the 240 volt level), the grounded conductor or any other path for that matter.

If there is excessive drop on a conductor then it is going to reduce the load in the case of resistance loads and the meter will see less power pass through it, if it is a motor load the current may increase - but voltage will drop - power will still mostly balance out.

Why do you think there is so much trouble with a aluminum conductor with a messenger strand? This has been relatively standard practice in many applications for decades and generally only has trouble when something fails, or is not sized correctly in the first place, both of which could just as easily happen with other conductor types.
 

bobby ocampo

Senior Member
What is the requirement for effectively grounded in single phase? How do we know if the installation is effectively grounded to assure that the OCPD will operate on overcurrent conditions?
 

bobby ocampo

Senior Member
Point of Attachment, in most cases the dividing line between utility ownership and customer. Bobby, can you give an example of the losses being unfairly charged to the customer? Nothing I've seen in this thread so far smells of a problem or the customer being overbilled. As always, I could be wrong.

Based on the orientation of the current coil of the meter and the potential coil of the meter for single phase, 3wire, We can see that the meter will measure the KWhr consumption of 240 volts load and 120 volts load even if the neutral conductor or the grounded service conductor is not connected in the meter.

In this regard, line losses from the neutral conductor or if the Distribution Utility used a messenger wire that has low conductivity, the meter will be able to read this losses of the conductor.
 

Attachments

  • Meter singlephase 3wire.jpg
    Meter singlephase 3wire.jpg
    25.2 KB · Views: 0

iwire

Moderator
Staff member
Location
Massachusetts
if the Distribution Utility used a messenger wire that has low conductivity,

They do not use a conductor of low conductivity.

They use a conductor of lower conductivity than copper.

I am wondering why you feel this is a problem when hundreds of thousands of service drops have been done this way successfully.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Based on the orientation of the current coil of the meter and the potential coil of the meter for single phase, 3wire, We can see that the meter will measure the KWhr consumption of 240 volts load and 120 volts load even if the neutral conductor or the grounded service conductor is not connected in the meter.

In this regard, line losses from the neutral conductor or if the Distribution Utility used a messenger wire that has low conductivity, the meter will be able to read this losses of the conductor.

The approximation that the standard meter makes to allow it not to have a voltage measurement relative to the neutral is that the L to N voltage will always be 1/2 of the L1-L2 voltage. To the extent that there is an unbalanced load on the service that will not be true because of the voltage drop in the service N conductor.
The result is that the load power on the higher loaded 120V circuit will be overestimated and the load power on the lighter loaded 120V circuit will be underestimated. Since the higher loaded circuit has a higher load :)angel:), the result will favor the power company.
Any voltage drop in either L1 or L2 will directly affect the voltage seen by the meter and so the customer will not be charged for the losses in those lines.

To the extent that the loading on the service is balanced between the two legs, the current on N will be small and the error in the billing will be correspondingly small. The billing error works out to be roughly proportional to the square of the unbalanced current.
 

kwired

Electron manager
Location
NE Nebraska
What is the requirement for effectively grounded in single phase? How do we know if the installation is effectively grounded to assure that the OCPD will operate on overcurrent conditions?
First there is a difference between grounding and bonding. How well a system is grounded is not as easy to tell, you need to measure resistance of electrodes that accomplish the grounding, but bonding is fairly easy to get a pretty good idea just looking at connections because the conductors, connections, devices used all should be low resistance to begin with. The equipment grounding system is then bonded to the grounding elecrodes which puts the EGS at same potential as the GES, but this GES can still have poor grounding resistance but is still a low impedance for faults to the EGS. That fault current is trying to get back to the source not the earth and will do so just fine through a low impedance equipment grounding path.
 

bobby ocampo

Senior Member
Any expert in metering who can explain how Kwhr is measured with single phase, 3wire?

If neutral is bonded in the service equipment, on the event of a single line to ground fault. will it affect the tripping of the OCPD if the conductor used has high resistance or less conductivity?
 
Status
Not open for further replies.
Top