power company recomendation

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don_resqcapt19

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Illinois
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retired electrician
I found the following statement on a 200 amp overhead service installation specification sheet.
Where non-metallic conduit (PVC) is the raceway, Illinois Power recommends the use of an equipment bonding jumper, sized per table on back of standard, to be installed from the meter socket to the customers main distribution panel. This additional bonding jumper is to be installed only in areas where local inspecting authority approve its use.
 

charlie

Senior Member
Location
Indianapolis
Re: power company recomendation

Sized per table on back of what standard? This doesn't make any sense to me since the bonding jumper will be in violation of 314.4. :confused:
 

bennie

Esteemed Member
Re: power company recomendation

I don't see that either code section is relevant to this issue.

The #4 appears to be required when the neutral is not landed in the meter base and when the meter is connected for only 120 volts.

The ampacity of the #4 only has to exceed the withstand rating of the meter housing. There is no overcurrent device to see a fault in the meter base.Only a burn will clear the fault.

The #4 only has to be capable of carrying the unbalanced load, in the event of a loss of the neutral, to be legal for paralleling.
 

don_resqcapt19

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Location
Illinois
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retired electrician
Re: power company recomendation

Bennie,
This is a spec sheet for a single phase 120/240 volt service and all Illinois Power conmpany meter cans have the grounded conductor bonded to the enclosure. They also specify that the GEC from the ground rod be landed in the meter enclosure.
Don
 

hurk27

Senior Member
Re: power company recomendation

Don this very question is one I tried to get an anser a few years ago. as what I see is required from the NEC is that the neutral-ground bond is to be only done once and if it is in the meter can then the main service panel should be treated like we do sub-panels and the neutral and grounds would be kept seperate. this would go along way to prevent the paralleling of the neutral. Also this would give us the single point bonding to the GEC. Here accross the border with Illinois we have the same type of meters as the neutral is bonded to the can. but with some more info I now belive that the intention is to only bring three conductors through to the panel H-H-N with out any other egc as the meter as discribed by the nec is part of the service drop and is on the utility side of the service.
Here is the definition that tells me the meter is still part of the service drop or lateral:

Service Conductors. The conductors from the service point to the service disconnecting means.

With that in mind.
Look at 230.1 Scope. at figure Figure 230.1 Services. you will see that the meter is before the service entrance cables or conductors.


(B) Method of Bonding at the Service. Electrical continuity at service equipment, service raceways, and service conductor enclosures shall be ensured by one of the following methods:
(1) Bonding equipment to the grounded service conductor in a manner provided in 250.8

Would'nt the grounding bar be the listed pressure connectors in bold below?

250.8 Connection of Grounding and Bonding Equipment.
Grounding conductors and bonding jumpers shall be connected by exothermic welding, listed pressure connectors , listed clamps, or other listed means. Connection devices or fittings that depend solely on solder shall not be used. Sheet metal screws shall not be used to connect grounding conductors to enclosures.

What I'm getting at is this. If we used SE cable to come in from the meter to the panel there has never been a requirment to have a seperate grounding conductor as the neutral was one in the same and was bonded at the meter inclosure and at the panel and this did not cause a paralleling of the neutral to form.
now if we ran the entrance conductors in a PVC from the meter to the panel where does the NEC require a EGC? as this would parallel the neutral and would be in violation of 250.30
Now if we ran the entrance conductors in RMC the neutral will be paralleled if we bond the neutral bar at the panel. and this would allow current to flow over the bonding wire.

250.24 Allows us to bond the grounded service conductor at the meter.
1) General. The connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.

Ok I'm ready to learn
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: power company recomendation

Wayne,
250.142(A) permits the use of the grounding conductor for all equipment grounding (bonding) on the line sied of and within the service equipment enclosure. 250.24(B) requires the grounded conductor to be bonded to the service equipment enclosure. 250.28 requires the main bonding jumper be installed in the service equipment enclosure. There are no code rules that would require a 4 wire installation between the meter and the service disconnect.
don
 

bennie

Esteemed Member
Re: power company recomendation

A meter base fits all the requirements for a disconnect switch. :eek:

[ August 29, 2003, 08:47 AM: Message edited by: bennie ]
 

don_resqcapt19

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Location
Illinois
Occupation
retired electrician
Re: power company recomendation

Bennie,
A plug in meter an its base is not suitable for use as a disconnect. It is not a listed load break device.
Don
 

bennie

Esteemed Member
Re: power company recomendation

I realize it is not regarded as a switch by the book, but in reality it is a pull out switch.

The old theory of the "walking duck" applies.

How about the plug in transfer switch?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: power company recomendation

Bennie,
The meter is not suitable as a load break device. It does not have any interrupting rating and is not available for the building occupant to use as the service disconnect. Numerous fire fighters have been injured when using plug in meters as service disconnects. Most of them not too severely, but only because they were protected by their turnout gear.
Don
 

wocolt

Member
Location
Ohio
Re: power company recomendation

Don:
Just my opinion, but to me they are saying/advocating a parallel path form the meter can to the Service panel.
Does it say where this bonding jumper is to be installed ? ...ie with the service conductors ? or by itself.

WOC
 

pierre

Senior Member
Re: power company recomendation

Con Edison, the utility company in lower NY is changing meters to allow for remote meter reading. They have a private contractor removing the existing meters and installing new meters. The method is for the men to remove the meter whether or not the homeowner is home or not. Also they are removing the existing meter with a load at times. Con Edison has now hired another contractor to come along and make the repairs for the damage caused by the arcing. These meters are not disconnects and this is one of the examples of why they should not be used or even thought of being used as such.
I only mention this to substantiate what Don has stated.

Pierre
 

bennie

Esteemed Member
Re: power company recomendation

I am not suggesting using a meter as a disconnect. I am only stating the meter base performs the same operation as a pull out switch.

My point is that the approval of a switch to be a disconnect, automatically makes for four wires after the switch, but not for a meter base, which electrically does the same thing.

There is disconnect switches that are not designed to open or close under load.

I have removed meters under load and reinstalled them. Some of the loads were substantial. Fireman are not permitted to remove meters due to the fact they may be on CTs.
 

bennie

Esteemed Member
Re: power company recomendation

Anyone who does not look at the disc should not be pulling meters.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: power company recomendation

Bennie,
Fireman are not permitted to remove meters due to the fact they may be on CTs.
Firefighters often remove meters and yes, some of these meters are CT meters. Just because meters have been removed under load does not make it safe and does not make the meter a service disconnect. Yes looking at the disk can help, but you never know if a large load is going to pull in just as you remove the meter.
Don
 

charlie

Senior Member
Location
Indianapolis
Re: power company recomendation

Gentlemen (and ladies if any are reading), this argument is valid if the current in the conduit caused a problem from the metering equipment to the service equipment. In other words show me the damage. If a bonding conductor were installed in nonmetallic conduit, it would indeed be in parallel with the grounded conductor and could (would?) overheat and cause the adjacent conductors to overheat. If the conduit is in parallel with the grounded conductor, the conduit will carry the extra current without heating much and it would not be a problem.

In my opinion, a proposal would not make it past a Code Making Panel for that reason. Why not make the proposal for the 2008 edition and see if it flies? :)
 

wocolt

Member
Location
Ohio
Re: power company recomendation

Don quoted the PoCos standard for areas, that if approved by the AHJ, shall install a bonding jumper from Meter base to Service panel.


quote:
--------------------------------------------------------------------------------
Where non-metallic conduit (PVC) is the raceway, Illinois Power recommends the use of an equipment bonding jumper, sized per table on back of standard, to be installed from the meter socket to the customers main distribution panel. This additional bonding jumper is to be installed only in areas where local inspecting authority approve its use.
--------------------------------------------------

If you bond the meter base where the neutral is tied to the service panel where the neutral is tied, is this not redundant ??
Is this not another parallel path for the return current?
Also doesnt it serve the same purpose as using metallic conduit from the meter base to the service panel ?
Where it must be bonded at one end.
My question to Charlie is how is this conductor going to over heat if the current is splitting at the service panel to the meter-can then recombining in the meter can.
The whole idea is ludicrous, but the power company has its own drummer too.
To me it seems that they are encouraging "Objectionable current" and also paralleling conductors less that 1/0.

As far as objectionable current goes is neutral current on a conductor or raceway because of a ground-neutral short, but this is a paralled neutral, so technically it cant be objectionable, but rather a violation of the parallel rule.
Do they give any reason for doing this ???

Wm.Colt
 

bennie

Esteemed Member
Re: power company recomendation

This is interesting. Paralleling appears to have a different technical application when it is done on the ground side.

On the active line, the ampacity of each conductor is added. On the ground side the ampacity of one path must be the calculated neutral ampacity, even with other paths. All paths do not have to be equal in impedance.

Case in point; The neutral with the service is in parallel with the earth. The neutral will carry full load, the earth will not.

There can be, and are, many conductors on the ground side, in parallel, that do not meet the 1/0 minimum size requirement.
 
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