Originally Posted By: tpriddy This post was automatically imported from our archived forum.
I’m talking about where the utility service is three wire (2 hots and one neutral) tied into the service panel along with a ground. The branch wiring in the house only has a hot and neutral going to the outlets. switches and fixtures. Is this allowed???
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
jpope wrote:
Sure, it's allowed.
The receptacles should be two-pronged and polarized. If there are three-pronged receptacles on a two wire system, they should be marked/labeled NO EQUIPMENT GROUND.
And a GFCI !!! 
Originally Posted By: lkage This post was automatically imported from our archived forum.
jpope wrote:
If there are three-pronged receptacles on a two wire system, they should be marked/labeled NO EQUIPMENT GROUND.
I recommend returning to 2 prong outlets or installing gfci outlets marked "no equipment ground", in locations where there are 3 prong outlets on 2 wire systems, for enhanced safety.
-- "I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
Originally Posted By: bbadger This post was automatically imported from our archived forum.
ddivito wrote:
As far as I know service entry wires should be 4 wires since 2000, but utilities do whatever they please.
You will not find any 240/120 utility service in the US with 4 wires.
A 240/120 service has 2 ungrounded conductors (hots) and a 'Multi-ground Neutral' (MGN)
If you see a utility service with 4 wires you are looking at a 3 phase service. (3 hots and MGN) or you are looking at a feeder not a service.
On the utility side of things they always combine the neutral and the grounding conductors into one normally bare conductor they call the Multi-ground neutral.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: ddivito This post was automatically imported from our archived forum.
I see 4 SE cables all the time in new construction these days. It is not three phase. Two conductors are hot. One is an insulated neutral and the fourth is ground (usually insulated as well) going back to the transformer. They will also run a bare ground wire to driven rods outside the house.
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
If you see that and you are not looking at a FEEDER from the first disconnecting means, you are looking at a violation. Do you report it?
250.28 Main Bonding Jumper.
For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor of the system within the enclosure for each service disconnect.
Originally Posted By: lkage This post was automatically imported from our archived forum.
ddivito wrote:
I see 4 SE cables all the time in new construction these days. It is not three phase. Two conductors are hot. One is an insulated neutral and the fourth is ground (usually insulated as well) going back to the transformer.
I've never seen that. I've always seen single phase like Bob described...two hots and a grounded conductor.
-- "I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
Originally Posted By: bbadger This post was automatically imported from our archived forum.
ddivito wrote:
I see 4 SE cables all the time in new construction these days. It is not three phase. Two conductors are hot. One is an insulated neutral and the fourth is ground (usually insulated as well) going back to the transformer. They will also run a bare ground wire to driven rods outside the house.
Single phase residential
Than your not looking at service conductors they would have to be feeder conductors which means there is a service disconnect between the 'SE 4 cable' and the power companies transformer.
Most all utilities operate either voluntarily or mandated under the NESC (National Electrical Safety Code) and that code does not provide 4 wire 240/120 single phase services.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
I bet there is going to be a service disconnect in the meter base and he is looking at the feeder to the house panel. The neutral and ground should be separated in that panel. The cabinet is bonded to the grounding bus, just like any other enclosure on the load side of the service disconnect.
Outside disconnects are becoming a lot more popular these days it seems.
Originally Posted By: roconnor This post was automatically imported from our archived forum.
tpriddy wrote:
The branch wiring in the house only has a hot and neutral going to the outlets, switches and fixtures. Is this allowed????
No and Yes
No ... It's not permitted to install only a 2-wire circuit for receptacles under current model codes. There must be a ground/bond wire.
Yes ... Existing 2-wire branch circuits are allowed by model codes to remain, if it met the codes in effect at the time of the installation (may be a "grandfathered" installation ... going way back though). In addition, there should only be a 2-prong or GFCI receptacle. A standard 3-prong outlet on that circuit would be a red flag.
However, even though it might be acceptable under codes to remain, you may want to consider recommending further evaluation or an upgrade. The wiring way be very old and at or near the end of it's useful life anyway.
Just my opinion and 2-nickels ... 
-- Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
ddivito wrote:
sorry guys. I'm seeing 4 wires from the meter to the outside disconnect and 4 wires from there to the interior branch circuit panel
The 4 wire from the disconnect to the house is proper.
A 4 wire from the meter to the disconnect is a code violation, on the customer side of the service point, so it is a NEC violation.
This usually comes about because the meter base is bonded to the neutral but that is still no reason to run 4 wires. All equipment on the utility side is bonded. There is some confusion about this but the consensus in Florida is this is a parallel neutral path. They don't even like metal raceways for this span
Originally Posted By: bbadger This post was automatically imported from our archived forum.
ddivito wrote:
sorry guys. I'm seeing 4 wires from the meter to the outside disconnect and 4 wires from there to the interior branch circuit panel
I agree with Greg this is a NEC violation if there is no disconnect in the meter.
As the meter socket is bonded and the service disconnect enclosure is bonded the SEs neutral and grounding conductors would be in parallel and that is a 310.4 violation unless the conductors are 1/0 or larger and are identical.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
ddivito wrote:
sorry guys. I'm seeing 4 wires from the meter to the outside disconnect and 4 wires from there to the interior branch circuit panel
Can we see some close ups of the installations you describe?
How were these 4 wires terminated in the first enclosure, from where they began at the drip loop?
Virginia may have some additional rules that call for the fourth wire, or maybe the "sectioned" type of wrap in the cable appears like two when they come into the light, I will bet that the two are bare, yes?
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
Quote:
3 wires as usual before the meter and 4 to the exterior disconnect
The 3 service entrance conductors that passed through the line side meter socket terminals were extended from the load side of the meter socket terminals with 4 wires into a disconnect?
Where was the disconnect located?
How could you see inside of the meter socket enclosure, and if you did how were the wires landed?
Originally Posted By: ddivito This post was automatically imported from our archived forum.
Cannot see into meter.
4 wires entering the disconnect panel located next to the meter.
two hots to the main disconnect,
one neutral to the busbar.
one insulated ground to the enclosure.
this same arrangement is repeated from the exterior 'main' panel to the branch circuit panel inside. However, the ground wire going into the interior panel is connected either at a lug on the enclosure with the neutral busbar bonded to the enclosure with a screw or strap or is connected to the neutral busbar with the neutral wire
Identifying marks are color stripes on the insulation
Black, red = hot
white = neutral
green = ground
This wiring arrangement just may be peculiar to my local power company.