URD Services

[jap]

Most all new services around our area are underground, a 200 amp Meter main pedestal set by the power company next to the utility pole.
It has the meter and a 200 amp main breaker in it.
I've looked in several ditches before they covered it all up.
The Electricians are running 4/0 URD from the pedestal to the house 3 wire no ground.
All of these services are inspected and passed without the 4 wire installed to the dwelling.
Is there something that allows this that I dont know about?
I see it all over the place.

 

[John120/240]

Sounds like it should be a sub panel installation in the residence. Are there any ground rods (or other means) at the meter/main breaker ? Call your local AHJ & get their reasoning on why it is done like this.

 

[jap]

They ground the Neutral to a ground rod at the Meter main then again at the structure.
Usually a 3r Loadcenter with feed thru lugs to catch the outside Condensing unit and storage shed then 4 wire entrance cable into an indoor panel bonded to the cold water pipe.

 

[ceb58]

Who's electricians are installing the wire from the load side of the disconnect to the dwelling? POCO's or owner/GC's electricians?

 

[resistance]

Who's electricians are installing the wire from the load side of the disconnect to the dwelling? POCO's or owner/GC's electricians?

Far as I know, the load side from the meter is owned by the owner of the property. So whomever the owner hires (If he/she is not doing the work themselves) to do the work is responsible for installing the conductors or cable.

 

[GoldDigger]

Although who installed the wiring is a good clue as to the jurisdiction over the wire and more importantly where the service point is.
It sounds like the panel st the house is being treated as the service point.
If that determination is valid, then how many locations before that point the utility chooses to ground the neutral is not an NEC issue.
So, what factors might conclusively establish where the service point and the designated service disconnect is?
If any loads like A/C or outbuilding are tapped off before the breaker at the house or the feed to an internal sub panel does not go through that breaker then it is probably not the service disconnect.
Where there are ground neutral bonds is also a clue.

Tapatalk!

 

[ActionDave]

May be a local thing. Until two years ago, in my corner of the world there was no requirement for a EGC from a meter pedestal. The AHJ considered the breaker in the pedestal part of POCO equipment.

I had no problem with that interpretation. There is no need for the fourth wire. There is never going to be a water pipe, or phone line, etc. between the house and the pedestal.

 

[kwired]

Here it depends if that pedestal or any other similar equipment (usually mounted on the pole itself) is utility provided or customer owned/controlled. If the utility provides it, we treat it as service conductors leaving it, should the equipment need replaced there is nothing keeping them from replacing it with something non fused at a later date should they so desire, and it will be replaced with no permits or inspections as it is utility operations. If it is not something the utility provides then the owner or contractor is installing it, it is subject to permits and inspections not only at initial installation but also is likely to be inspected should it need replaced.

This has been the way it was even before 2005(?) NEC when they started to require separate EGC to other buildings or structures. Back then what I remember being questioned the most is whether or not a meter main installed by POCO could serve as the service disconnecting means for a mobile home. Back then the answer was no, because if the POCO should happen to change it to a non fused unit we now have an improper installation. We are seeing disconnects at farms that have overcurrent protection, and others that do not, all from same POCO. It is easiest to assume that to be service conductors leaving that location and get rid of all confusion, basically the service point is the load side of that disconnect and it doesn't matter if it has overcurrent protection or not it is treated as service conductors - but other AHJ's may have a different view.

 

[jap]

The Meter Main is provided by the PC but the conductors are installed to the dwelling by the Electrician.
Regardless, in my mind,since there is not a EGC installed to the dwelling the Neutral and Grounds are landed on the same bar and the Neutral bar is bonded to the Panel. If you were to loose a neutral on the URD from the Pedestal to the house then you would have objectional current flowing on all of the normally non current carrying items instead of simply not working.

 

[kwired]

The Meter Main is provided by the PC but the conductors are installed to the dwelling by the Electrician.
Regardless, in my mind,since there is not a EGC installed to the dwelling the Neutral and Grounds are landed on the same bar and the Neutral bar is bonded to the Panel. If you were to loose a neutral on the URD from the Pedestal to the house then you would have objectional current flowing on all of the normally non current carrying items instead of simply not working.

Yes but it was that way for many years when we were allowed to use the grounded conductor for equipment grounding at separate buildings, and is still that way at services where the grounded conductor is compromised.
Those separate buildings do have grounding electrode systems to help stabilize the voltage to earth, but they still are not enough in some cases and are more than necessary in others. The only way to completely avoid this is to start running the equipment grounding conductor all the way to the source, and even then depending on design issues there could still be a little risk of failures, plus without any monitoring for ground faults on the grounded conductor can end up with just as much or even more problems anyway.

 

[jap]

It's just hard to emphasize the importance of the 4th wire in most all other cases like we do and yet this is seems to still be ok.

 

[JDB3]

One power company around here does not want the 4th wire in their pedestal combination meter/disconnect as there is no place provided to connect it to. I have tied a #6 bare copper to a ground rod in the ditch, to the re-barb in the slab, to my panel. Then separated the neutrals & grounds in my panel. I normally try to stub my conduit up (in the slab) inside of the garage wall where all of my runs go to.

 

[kwired]

One power company around here does not want the 4th wire in their pedestal combination meter/disconnect as there is no place provided to connect it to. I have tied a #6 bare copper to a ground rod in the ditch, to the re-barb in the slab, to my panel. Then separated the neutrals & grounds in my panel. I normally try to stub my conduit up (in the slab) inside of the garage wall where all of my runs go to.

Please clarify, depending on exactly what you are doing you could be setting yourself up for more danger than not having the 4th grounding wire in the feeder. If the earth is the sole return path for ground fault current you are absolutely wrong, and are going to get someone injured or killed by this practice.

 

[kwired]

It's just hard to emphasize the importance of the 4th wire in most all other cases like we do and yet this is seems to still be ok.

It is exactly what we have done until 2005 NEC came out in almost all instances. It is exactly what the POCO is doing not only from the service point back to the transformer, but is also what they are doing with their medium voltage distribution in most cases. There very is current from their primary neutral conductor flowing through the service equipment at your home, it can not be avoided when nearly every structure in the system has a grounding electrode attached to the grounded conductor.

I'm not saying I necessarily like it, but it is what it is, I also don't see having an overcurrent device at the pole or remote pedestal really makes any difference, but that is all NEC takes to call it a feeder instead of a service. If we truly want to eliminate some of the possibilities then we need to either run an EGC all the way to the source and keep it isolated from the grounded conductor, but some kind of monitoring becomes somewhat necessary otherwise a neutral to ground fault essentially wipes out the whole intention. Or we need to stop using circuits that utilize the grounded conductor, no more 120 volt loads, no more 277 volt loads, use neutral conductors only for equipment grounding purposes, that is not happening anytime soon either.

 

[jap]

It is exactly what we have done until 2005 NEC came out in almost all instances. It is exactly what the POCO is doing not only from the service point back to the transformer, but is also what they are doing with their medium voltage distribution in most cases. There very is current from their primary neutral conductor flowing through the service equipment at your home, it can not be avoided when nearly every structure in the system has a grounding electrode attached to the grounded conductor.

I'm not saying I necessarily like it, but it is what it is, I also don't see having an overcurrent device at the pole or remote pedestal really makes any difference, but that is all NEC takes to call it a feeder instead of a service. If we truly want to eliminate some of the possibilities then we need to either run an EGC all the way to the source and keep it isolated from the grounded conductor, but some kind of monitoring becomes somewhat necessary otherwise a neutral to ground fault essentially wipes out the whole intention. Or we need to stop using circuits that utilize the grounded conductor, no more 120 volt loads, no more 277 volt loads, use neutral conductors only for equipment grounding purposes, that is not happening anytime soon either.

I'm just sayin on an install where the Meter Main is remote from the stucture its feeding, it seems like a good place to bond the Netral there,and pull a seperate EGC to the structure. That way if the neutal opened wether in the service or the feeder, the objectional current wouldnt flow on the normall non current carrying conductors since they would be seperated at the structure.its also very unlikely the power company would ever change out a meter/main pedestal to just a meter pedestal. I would think they would replace it with the exact same thing.

 

[jap]

One power company around here does not want the 4th wire in their pedestal combination meter/disconnect as there is no place provided to connect it to. I have tied a #6 bare copper to a ground rod in the ditch, to the re-barb in the slab, to my panel. Then separated the neutrals & grounds in my panel. I normally try to stub my conduit up (in the slab) inside of the garage wall where all of my runs go to.

True,The power company doesnt want the 4th wire from thier source to the first means of disconnect

I hope you bonded the Neutral to Ground in the Panel otherwise your panel has no way to clear a fault.


If the breaker below the meter in a Meter/Main Pedestal installation is considered the customers first means of disconnect and not the power company's equipment, then the Neutral would be bonded to ground at that point and a seperate Neutral and EGC would be run to the structure from there. The Neutral, EGC and the Grounding Electrode conductor would all land at the same spot at the meter main. The grounding and bonding at the structure would only entail the EGC, not the Grounded Conductor (Neutral). it would be kept seperate.There would only be 3 wire (If Single Phase) or 4 wire (if 3 phase) from the Power Comany's Transformer to the meter.

 

[jap]

Please clarify, depending on exactly what you are doing you could be setting yourself up for more danger than not having the 4th grounding wire in the feeder. If the earth is the sole return path for ground fault current you are absolutely wrong, and are going to get someone injured or killed by this practice.

I agree with Kwired completely and have witnessed and repaired recent installations that would never clear a fault.

 

[kwired]

I'm just sayin on an install where the Meter Main is remote from the stucture its feeding, it seems like a good place to bond the Netral there,and pull a seperate EGC to the structure. That way if the neutal opened wether in the service or the feeder, the objectional current wouldnt flow on the normall non current carrying conductors since they would be seperated at the structure.its also very unlikely the power company would ever change out a meter/main pedestal to just a meter pedestal. I would think they would replace it with the exact same thing.

Nothing wrong with 4th conductor even if it is service conductors you are dealing with from a theory and performance view, but you do violate some codes to install it that way, as grounded service conductors are supposed to be bonded to everything up to the service disconnecting means. My point all along here is putting overcurrent devices in those ungrounded conductors out at the street or back alley does nothing to change how much current flows or how it flows in the grounded conductor(s). All it changes is the location of the service disconnecting means. Install exactly the same thing but omit any overcurrent device at the supply end and you have true service conductors and nobody questions needing a 4th conductor there.

Here there is a lot of rural customers, it is very common for those customers to be supplied from a pole with a meter and a disconnect, all supplied by the POCO and with quite a bit of variance in what it may be, and every few years they may change what they are commonly using as well. Some get a meter and separate fused disconnect, some get a meter and a separate unfused disconnect, some meter/main with fuse or with breaker, some get an all in one meter and transfer switch for connecting alternate standby sources to (POCO can install these but contractors can't because they are not listed - mostly because there is no overcurrent devices in them). Customer often has some options, and will be charged for it, but POCO installs and maintains it. There is no guarantee what will be on that pole, so the general rule is if the POCO supplies it treat conductors that leave as service conductors, even if they currently have overcurrent protection, because if that unit at the pole gets changed it may be replaced with something that does not have overcurrent protection. I don't have a problem with that approach, it keeps it simple, is no different than we done for years with little problems.

 

[mwm1752]

After the first point of disconnect NEC requires a EGC for the feeder. Remote meter installations like this are making us tie all grounding systems, as this one to, the first point in which the grounded conductor is bonded to the electrode systems. I've felt that the meter main is not a structure but many in this forum have disagreed(It is electrical equipment)IMO. I also think that an electrode system in designed for lighting strikes so that induced voltage on the wiring system has a quick path to earth in order to minimize damage. So in remote intalls such as these, is seems like we are giving path along the UG service feeder to connect both wiring & electrical equipment unneccessarially to the remote disconnect and the structure disconnect. The 3 wire install would still have the grounded conductor as a path, but without the EGC the strike would seem to be directed to earth quicker with separate electrode systems. IMO

 

[kwired]

After the first point of disconnect NEC requires a EGC for the feeder. Remote meter installations like this are making us tie all grounding systems, as this one to, the first point in which the grounded conductor is bonded to the electrode systems. I've felt that the meter main is not a structure but many in this forum have disagreed(It is electrical equipment)IMO. I also think that an electrode system in designed for lighting strikes so that induced voltage on the wiring system has a quick path to earth in order to minimize damage. So in remote intalls such as these, is seems like we are giving path along the UG service feeder to connect both wiring & electrical equipment unneccessarially to the remote disconnect and the structure disconnect. The 3 wire install would still have the grounded conductor as a path, but without the EGC the strike would seem to be directed to earth quicker with separate electrode systems. IMO

That first point of disconnect also has to qualify as a "service disconnecting means". Most "meter mains" will qualify, but not all we are seeing around here have overcurrent protection and because of that do not qualify as a "service disconnecting means".

Once you are beyond the service disconnecting means you no longer have service conductors you have feeders or branch circuits and can no longer use the grounded circuit conductor for equipment grounding purposes - with limited exceptions in situations where it once was allowed.