Grounding

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JDB3

Senior Member
Location
San Antonio, Texas
In an area where I do work, there is no inspections. The utility company, for 200 amp services mount a combination meter/panel onto their pedestal.
We furnish/install the single bolt on breaker for it. There is no provision for a grounding wire.
We then install the wire from the panel to the house.
I install a #4 solid copper wire (sticking up from the slab to go into the panel at the house) to tie to the re-bar in the slab, stick out enough to tie onto a ground rod in the ditch (that has the conduit from the panel (on their pedestal) to panel (in this case) located in garage.
Since there is only a 3-wire feeder from utility power source, should the grounding wire @ the house panel be separate from the neutral bar or should they be kept separate? :?

Thanks in advance for the input. :D
 
If you have a 3 wire feeder to a structure and there is a fault to ground at the structure, think about how that fault current will need to get back to the source to clear the fault.



JAP>
 
JDB3 said:
Since there is only a 3-wire feeder from utility power source, should the grounding wire @ the house panel be separate from the neutral bar or should they be kept separate? :?
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So the choices are separate or separate? I'm sure that's not what you meant, and why your post drew questioning emoticons.

Since you have only a three-wire feeder, the grounding electrode system must tie to the feeder neutral, as in any M/B panel.
 
LarryFine said:
So the choices are separate or separate? I'm sure that's not what you meant, and why your post drew questioning emoticons.

Since you have only a three-wire feeder, the grounding electrode system must tie to the feeder neutral, as in any M/B panel.
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At the pedestal, not the premises breaker panel, correct? The pedestal is the first disconnecting means.
 
ActionDave said:
Not always. Some jurisdictions will call the meter ped power company equipment and outside the scope of the NEC.
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The OP said he had to furnish the breaker. Would that change or color your opinion for this particular case?
 
Sorry, in my opening post I meant to ask, "Should the grounding (ground) wires be kept separate from the grounded (neutral) wires or should they be tied together ?
Also, is a #4 grounding (ground) wire required or is a #6 sufficient?
 
JDB3 said:
Sorry, in my opening post I meant to ask, "Should the grounding (ground) wires be kept separate from the grounded (neutral) wires or should they be tied together ?
Also, is a #4 grounding (ground) wire required or is a #6 sufficient?
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Whether or not the pedestal is to be considered service disconnect or not is one thing, but if you only have three conductors to the building, the only return path if you don't bond at the building is via your grounding electrode(s) and earth - not normally going to be low enough resistance to assure proper functioning of overcurrent protection during ground fault conditions.

Right or wrong if you only have the three wire feed you have to bond at the load end - before 2008(?) NEC it would have been normal to run three wire and bond at the supplied structure. Now it really depends on whether or not that pedestal is considered on customer side of the service point or not. If the pedestal is deemed to be the service disconnecting means, only existing installations are allowed to do it the old way with three wires, new installs require the fourth EGC to be run.
 
JDB3 said:
Sorry, in my opening post I meant to ask, "Should the grounding (ground) wires be kept separate from the grounded (neutral) wires or should they be tied together ?
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As I stated above, the grounding system must be tied to the feeder neutral. This is what a main bonding jumper does.

For example, if your panel has an insulated (from the enclosure) neutral bus and a ground bus attached to the enclosure, the green screw or strap that bonds the enclosure to the neutral performs this function.

Also, is a #4 grounding (ground) wire required or is a #6 sufficient?
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For ground rods, a #6 is all that is ever required. For any other electrodes, such as water piping, the conductor size is based on the service size, so #4 is required for your 200 amp service.
 
kwired said:
Whether or not the pedestal is to be considered service disconnect or not is one thing, but if you only have three conductors to the building, the only return path if you don't bond at the building is via your grounding electrode(s) and earth - not normally going to be low enough resistance to assure proper functioning of overcurrent protection during ground fault conditions.

Right or wrong if you only have the three wire feed you have to bond at the load end - before 2008(?) NEC it would have been normal to run three wire and bond at the supplied structure. Now it really depends on whether or not that pedestal is considered on customer side of the service point or not. If the pedestal is deemed to be the service disconnecting means, only existing installations are allowed to do it the old way with three wires, new installs require the fourth EGC to be run.
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Power/Utility company's box does not have a place for grounding (ground) conductor to be connected, & they prefer that you do not add a lug there.
 
JDB3 said:
Power/Utility company's box does not have a place for grounding (ground) conductor to be connected, & they prefer that you do not add a lug there.
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Not sure what your considering a "Box" but, I've never seen a Service Pedestal that did not have a lug space for the grounding electrode conductor.

JAP>
 
jap said:
Not sure what your considering a "Box" but, I've never seen a Service Pedestal that did not have a lug space for the grounding electrode conductor.

JAP>
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Box meaning the meter enclosure with space for bolt-in breaker below the meter. All one enclosure. And these have just a double barrel lug for power companie's ground (neutral) wire & your ground (neutral wire).
 
I'm with ya.

I always used to try and leave a small service curve in my wiring prior to termination.

I'm more and more getting away from that habit with the lugs being as close as they are to the entrance of the enclosures now a days.

JAP>
 
JDB3 said:
will try to get one tomorrow (Thursday). One difficult thing about these is that there is only 4" from connector entering bottom of enclosure to bottom of breaker.
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Sounds like something not listed, if it were there should be more wire bending space then that - exception maybe if lay in type lugs - but that is more common on meter sockets then on breakers.
 
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