SEC and panels also CEU course material

[David L. Hostetter]

These questions I posed origanlly to Nick and he referred them to here.

I have another question, maybe should be posted in the electrical message section.
Bare with as this is complicated with several directions and inputs.
Around here most service entrances enter through the feeder to the meter base then into the service panel where the main disconnect is located.
The question is, when plastic conduit is used from the meter base through the exterior wall into the service panel and an additional bare grounding conductor is or is not present. What issue is present or isn't?
I have previously written up the missing bare conductor as not bonding the metal meter base to the metal service panel as noted in the #2 question below. This goes back to some CEU training given by a member of the Indiana licensing board stating the bonding conductor was required due to the plastic conduit.
In discussion with one of the local Municipal electrical depts. they stated that this is a violation when the meter base is bonded to the service panel as this is considered a parallel neutral (grounded conductor) by the NEC. What they are telling local electrical contractors servicing this Municipal area is to run the bare grounding conductor from the grounding rod(s) thought the meter base (without connecting in meter base) to the service panel. Is this scenario correct?
a. How and what do I write up when we don't open meter bases?
b.Do we write up that there is a bare grounding conductor and as not knowing how it is connected or not in the meter base?
c.Do we write it up as missing the continuous grounding through conduit not electrically linking the 2 panels if a bare conductor is not present.
d.Is the feeder grounded conductor actually bonding the two units?
e.I know the AHJ is the last word but, or do we just refer it back to a licensed electrical trade or contractor to sort out the mess?

Question #2

Should the word {metallic} be added as plastic conduit will not conduct linking the 2 panels? otherwise a grounding conductor would be required.

Distribution panels


Or load side panels are downstream from the panel containing the main service disconnect(s). In these panels the Neutral and Grounds should be separate and the neutral bus should be isolated from the panel enclosure.
There are 2 methods of providing ground continuity back to the service panel.
4 conductor feeders with:
2 hot or ungrounded conductors
1 Neutral or grounded conductor
1 grounding conductor
3 conductor feeders with:
2 hot or ungrounded conductors
1 Neutral or grounded conductor
continuous grounding through {metallic} conduit electrically linking the 2 panels

[Mike Whitt]

David

From the point of attachment for an overhead service to the main breaker in the panel can be installed with a service entrance cable. This cable will have two insulated conductors and one bare conductor. The bare conductor is the incoming neutral and the others are the ungrounded (hot) conductors.
This bare neutral will terminate in a lug at the meter base. This lug is bonded to the meter can. The bare neutral continues on to the neutral bar in the main breaker enclosure. Here again the neutral is required by the NEC to bond to the enclosure again.
Installing an equipment grounding conductor would cause the equipment grounding to also carry the current that would be on the bare neutral conductor.

If a raceway is installed the neutral will be an insulated conductor. It will also be bonded to both enclosures. I never use a metal raceway between the meter and the main simply because the metal raceway would also be carrying part of the current that was on the neutral.

250.6 Objectionable Current.
(A) Arrangement to Prevent Objectionable Current. The grounding of electrical systems, circuit conductors, surge arresters, surge-protective devices, and conductive normally non–current-carrying metal parts of equipment shall be installed and arranged in a manner that will prevent objectionable current.

The NEC even requires that there be no objectionable current on the metal raceway that would be installed between the meter base and the service disconnect enclosure.

Also if the neutral ever became lose then the metal raceway would become the neutral conductor.

[David L. Hostetter]

So what your saying then is the local muni is wrong in requiring the grnd wire through to the main also Is then what your saying that the ground rod(s) should be to the meter base with the neutral bonding the main to the meter base? Most time here the neutral is insulated with white tape marking.

[Mike Whitt]

Originally Posted by dhostetter

So what your saying then is the local muni is wrong in requiring the grnd wire through to the main

No it is not what I am saying it is what the NEC is saying

310.4 Conductors in Parallel.
(A) General. Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG and larger, comprising each phase, polarity, neutral, or grounded circuit conductor shall be permitted to be connected in parallel (electrically joined at both ends).

Note the words in parenthesis about being joined on both ends. By the very nature that meter bases are manufactured the neutral is bonded to the enclosure.

The neutral terminal bar in every meterbase on the market today is bonded to the enclosure before it leaves the factory. It doesn’t matter if the conductor that lands on that terminal is insulated or not the minute it lands on the neutral terminal in the meter base it also lands on the meter enclosure.

If you can look at a meter base before it is installed you will see that the terminal is connected to the enclosure and you can use a continuity tester to see that there is continuity between the terminal and the enclosure before any wires are connected.

Originally Posted by dhostetter

also Is then what your saying that the ground rod(s) should be to the meter base with the neutral bonding the main to the meter base?

The grounding electrode conductor can be terminated any where from the weather head to and including the terminal bar in the panel.

250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5).
(1) General. The grounding electrode conductor 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.

The ground rod is one of the grounding electrodes outlined in 250.52.
In my area we land the ground rod in the meter base simply because it is the easy place to do so.

Originally Posted by dhostetter

Most time here the neutral is insulated with white tape marking.

Again in doesn’t matter if the conductor is insulated or not it stills bonds to the meter can and the service enclosure therefore making any other conductor (equipment grounding) installed from the meter base and the service main a parallel installation and a violation of the NEC