Originally Posted By: wdecker This post was automatically imported from our archived forum.
is a seperate, green ground wire required for outlet wiring. I hear different things from different code inspectors and electricians.
I believe that for a 120V outlet, there should be a hot, neutral and a ground wire, attaching to the proper screws at the outlet.
Electricians tell me that since the wire is in conduit and since the conduit is grounded that the outlet attaching to the box (metal) will provide a ground.
I counter argue that in this case, what happens when the bonding between the different sections of conduit fail (as when you have unqualified modifications, usually by the owner).
They respond, well thenm, it is against code because the owner did work without a permit and having it done by a union guy.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Greg,
Isn't the grounding screw required to have a wire attached to the metal box which is providing the grounding? With a green grounding clip, or green grounding screw, I believe!
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
If you use a metal wiring method listed for grounding, metal boxes and self grounding devices you don’t need any green screws or ground wires. Personally I like seeing the ground wire and the State of Florida always spec’ed it on the jobs I inspected but it is not code.
Originally Posted By: bbadger This post was automatically imported from our archived forum.
wdecker wrote:
I believe that for a 120V outlet, there should be a hot, neutral and a ground wire, attaching to the proper screws at the outlet.
Electricians tell me that since the wire is in conduit and since the conduit is grounded that the outlet attaching to the box (metal) will provide a ground.
The NEC does not require a separate grounding conductor with metal raceways. If you have access to the NEC you can look at 250.118 for a list of acceptable grounding means.
Here is part of 250.118
Quote:
250.118 Types of Equipment Grounding Conductors.
The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:
(1)A copper, aluminum, or copper-clad aluminum conductor. This conductor shall be solid or stranded; insulated, covered, or bare; and in the form of a wire or a busbar of any shape.
(2)Rigid metal conduit.
(3)Intermediate metal conduit.
(4)Electrical metallic tubing.
(5)Flexible metal conduit where both the conduit and fittings are listed for grounding.
It continues on with 9 more items, but you get the idea.
wdecker wrote:
I counter argue that in this case, what happens when the bonding between the different sections of conduit fail (as when you have unqualified modifications, usually by the owner).
They respond, well thenm, it is against code because the owner did work without a permit
I agree with 'them', I would also add that many times even if there is a grounding 'wire' that inexperienced handymen leave it disconnected as the item they are wiring works without it.
wdecker wrote:
My point is safety. They don;t seem to get it.
Any great (or not so great) thoughts?
Will I will call these 'not so great'  the basic purpose of the NEC is stated in 90.1
Quote:
90.1 Purpose.
(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
The code can not safeguard people from their own actions. In other words I can wire a building completely (to the best of my ability) code compliant. The first person to go and modify that wiring can certainly make it non-compliant.
I don't care about union, non-union, handymen, electrician etc. all that matters is if they understand all the rules. Making a something work is easy, making something work code compliantly is another thing.
In MA where I live electricians need licenses however a homeowner can work on the home they live in, they still have to get a permit and get inspections.
I will also add that a properly installed steel raceway provides a better grounding path than the copper conductor inside it. Steel is less conductive than copper but there will be much more of it.
That said 99% of the jobs we do the engineers will specify copper grounding conductors.
Now we get to 90.1(B) and (C)
Quote:
90.1(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance will result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.
(C) Intention. This Code is not intended as a design specification or an instruction manual for untrained persons.
My point is the NEC is a minimum safety code, good design is left to the installers and engineers.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Bob,
Is the strap on the receptacle allowed to be used for grounding, or does it have to be installed with a grounding clip or grounding screw onto the metal box?
Originally Posted By: bbadger This post was automatically imported from our archived forum.
jmyers wrote:
Bob,
Is the strap on the receptacle allowed to be used for grounding, or does it have to be installed with a grounding clip or grounding screw onto the metal box?
I had stayed clear of this question, not because it is not a good question, only because it is not a yes or no answer.
If the receptacle is UL listed as 'self grounding' (all the new ones I see are) and if it is installed in a flush mounted (typical in the wall outlet) steel box then, NO it does not need a separate grounding conductor from the box to the green terminal on the receptacle.
Other than that you almost always need a grounding conductor from box to receptacle.
I prefer always using the grounding conductor but that is just personal choice.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN