Grounding an outlet Puzzle

[dsydvf]

Greetings,

I have metal box feed by conduit in a room in my basement that has a switch and a standard power outlet in the box. The switch controls a single overhead lightbulb in the room.

Problem: The Outlet is not grounded properly (confirmed by device that checks for grounding and polarity)
My Goal is to ground this outlet.

The source wires (black, white, green) coming from the conduit are pictured here in the top left hand corner area (source wires). The green wire is currently attached to the ground terminal on the light switch.

Very strange: I decided to simply move the ground wire from the switch ground terminal to the outlet ground terminal. When I do this the outlet is fine (ground and polarity OK for outlet) however, the light switch no longer works when the green wire is on the outlet ground terminal.
I put the green wire back to the switch ground terminal and the light works fine again (the outlet works too but not grounded as before).

I then tried running a jumper from the grounded switch terminal to the ground terminal of the outlet (Bad Idea as it sparked and tripped the breaker instantly).

I don't understand how this was wired back in the day. If you have any ideas I would appreciate it. Many Thanks!

 

[jeffmattero76]

What is the white wire (the neutral) connected toif anything?

Until I have more info, I will take a guess. This guess assumes that the incoming cable from the panel is a white, black, and either bare or green. I am also assuming that there is a cable that feeds the luminaire that is also a black, white and green or bare.

If that is true, connect the two white wires together with a wire nut. Put the incoming black wire on one of the switch screws, and put the other black wire on the other switch screw. Hook the greens together with a 6 inch piece of green or bare wire(called a pigtail) and connect that pigtail to the ground screw on the switch. When the switch is screwed into the metal box, that metal box should show as being grounded (via the screw that holds the switch in the box).

Greetings,

I have metal box feed by conduit in a room in my basement that has a switch and a standard power outlet in the box. The switch controls a single overhead lightbulb in the room.

Problem: The Outlet is not grounded properly (confirmed by device that checks for grounding and polarity)
My Goal is to ground this outlet.

The source wires (black, white, green) coming from the conduit are pictured here in the top left hand corner area (source wires). The green wire is currently attached to the ground terminal on the light switch.

Very strange: I decided to simply move the ground wire from the switch ground terminal to the outlet ground terminal. When I do this the outlet is fine (ground and polarity OK for outlet) however, the light switch no longer works when the green wire is on the outlet ground terminal.
I put the green wire back to the switch ground terminal and the light works fine again (the outlet works too but not grounded as before).

I then tried running a jumper from the grounded switch terminal to the ground terminal of the outlet (Bad Idea as it sparked and tripped the breaker instantly).

I don't understand how this was wired back in the day. If you have any ideas I would appreciate it. Many Thanks!


View attachment 21173

 

[Snoonyb]

Welcome.

Whoever wired this circuit used the green conductor as a switch leg.

Add a white conductor from the switch to the light fixture replacing the green, then bond the green conductor to the 4s box and if you chose pigtail both the switch and recep. to the bonded green conductor.

 

[hornetd]

Snoonyb is right about the green wire having been used as a switch leg but the color for the return wire from the switch when wired in conduit my not be White, Natural Grey, Green, nor green with one or more yellow stripes. Since black was not used in the original wiring that is one obvious choice. Another would be blue. You can actually use any color except the 4 that I have already named. Hopefully the conduit extends all the way back to the lighting outlet box.

--
Tom Horne

 

[dsydvf]

Thank You. Here is my understanding then....

If this is acceptable, I can pull about 12 feet of black wire out of some Romex I have that I will probably otherwise never use (the approx. distance from the switch to the externally mounted light bulb box). This wire is 14 or 16 gauge.

Thus, I will replace the green wire that ties the bulb to the switch (the current switch leg) with this black wire. Once that is done I will then secure a section of the green wire to the box itself, while pig tailing it in such a way that it will connect to both ground terminals (one to the ground terminal on the switch and one to the ground terminal on the outlet). I would be using the box/conduit system as a ground?

Thanks again

 

[Snoonyb]

Before you do this, please open the fixture box and provide a photo of the wiring there-in.

The romex should be imprinted, somewhere in the length and will probably be either 12/2 or 14/2.

Strip the romex and using the green conductor as a pull tape, pull both the black and the bare copper conductor too the fixture box.

 

[JoeD]

Wire from inside a 14/2 cable is not certified to be pulled in conduit. You need a piece of actual THHN rated wire. If the circuit is 15 amp it must be #14 not #16.

 

[WyrTwister]

Using a green as a switch leg , very bad practice .

Truth is , if the conduit is grounded properly , so will be the receptacle when all is put back together .

Wyr
God bless

 

[bud16415]

How about replacing the outlet with a GFCI outlet and comply with code that way?

 

[WyrTwister]

That would work , but if the receptacle is serving electronics , it still will not provide an earth ground .

Wyr
God bless

 

[hornetd]

How about replacing the outlet with a GFCI outlet and comply with code that way?

If you apply a ground pathway impedance tester, such as the one built into the IDEAL SureTest® Circuit Analyzer, you will be able to measure the actual impedance of the Equipment Grounding Conductor pathway. It is often true that metal raceway will have a lower impedance as a Equipment Grounding Conductor than a separate conductor which is pulled into the raceway with the circuit conductors would have. Even if you were to pull a separate Equipment Grounding Conductor into the metal raceway it would still have to be bonded to the metal raceway system at any point were a receptacle outlet is installed. The only exception would be for Isolated Ground Receptacle Outlets which are only installed were the electronics which are part of the served load require a Grounding pathway which is kept as free as practicable from induced electrical noise. Most Authority's Having Jurisdiction will require that there be a requirement for an isolated ground included in the instructions which are part of the listing and labeling of a cord and plug connected device before they permit the installation of Isolated Ground Receptacles.

--
Tom Horne

 

[hornetd]

How about replacing the outlet with a GFCI outlet and comply with code that way?

A Ground Fault Circuit Interrupter may not be used in place of a connection to an Equipment Grounding Conductor where an Equipment Grounding Conductor is available in the circuit.

--
Tom Horne

 

[hornetd]

Wire from inside a 14/2 cable is not certified to be pulled in conduit. You need a piece of actual THHN rated wire. If the circuit is 15 amp it must be #14 not #16.

To expand a little on this answer it is unusual but not unheard of for a cable manufacturer to label the individual conductors in a Non Metallic cable because of the extra expense. If a conductor is not labeled as required by the locally adopted code it cannot be used except as part of the cable assembly which is labeled as required by the adopted code. The conductor must be labeled so that it can be inspected for it's suitability for use in the installation. What JoeD said is not always true because there are several other types of wire which could be used in the installation. But he is dead on when he says that you will need labeled wire and that 14 American Wire Gauge is the minimum size that could be used to carry 15 Amperes.

--
Tom Horne

 

[hornetd]

Greetings,

I have metal box feed by conduit in a room in my basement that has a switch and a standard power outlet in the box. The switch controls a single overhead lightbulb in the room.

Problem: The Outlet is not grounded properly (confirmed by device that checks for grounding and polarity)
My Goal is to ground this outlet.

The source wires (black, white, green) coming from the conduit are pictured here in the top left hand corner area (source wires). The green wire is currently attached to the ground terminal on the light switch.

Very strange: I decided to simply move the ground wire from the switch ground terminal to the outlet ground terminal. When I do this the outlet is fine (ground and polarity OK for outlet) however, the light switch no longer works when the green wire is on the outlet ground terminal.
I put the green wire back to the switch ground terminal and the light works fine again (the outlet works too but not grounded as before).

I then tried running a jumper from the grounded switch terminal to the ground terminal of the outlet (Bad Idea as it sparked and tripped the breaker instantly).

I don't understand how this was wired back in the day. If you have any ideas I would appreciate it. Many Thanks!


View attachment 21173

One thing that I overlooked when I first looked at this picture. View attachment 21173 Since you have opened the box to work on it you must bring the mounting of the receptacle up to code. A receptacle can no longer be supported by it's cover screw threads only. You have 2 choices. One is to buy a new cover which will have the 2 mounting holes were the yoke's mounting holes are located and will include all of the needed mounting hardware. Then use 2 8/32 screws, 2 8/32 hex nuts, and 2 star or split washers to hold the receptacle in place inside the cover against the repetitive insertion and extraction of plug blades.

406.5 Receptacle Mounting. Receptacles shall be mounted in identified boxes or assemblies. The boxes or assemblies shall be securely fastened in place unless otherwise permitted elsewhere in this Code. Screws used for the purpose of attaching receptacles to a box shall be of the type provided with a listed receptacle, or shall be machine screws having 32 threads per inch or part of listed assemblies or systems, in accordance with the manufacturer’s instructions.

(C) Receptacles Mounted on Covers. Receptacles mounted to and supported by a cover shall be held rigidly against the cover by more than one screw or shall be a device assembly or box cover listed and identified for securing by a single screw.

--
Tom Horne

 

[Snoonyb]

One thing that I overlooked when I first looked at this picture. View attachment 21173 Since you have opened the box to work on it you must bring the mounting of the receptacle up to code. A receptacle can no longer be supported by it's cover screw threads only. You have 2 choices. One is to buy a new cover which will have the 2 mounting holes were the yoke's mounting holes are located and will include all of the needed mounting hardware. Then use 2 8/32 screws, 2 8/32 hex nuts, and 2 star or split washers to hold the receptacle in place inside the cover against the repetitive insertion and extraction of plug blades.

406.5 Receptacle Mounting. Receptacles shall be mounted in identified boxes or assemblies. The boxes or assemblies shall be securely fastened in place unless otherwise permitted elsewhere in this Code. Screws used for the purpose of attaching receptacles to a box shall be of the type provided with a listed receptacle, or shall be machine screws having 32 threads per inch or part of listed assemblies or systems, in accordance with the manufacturer’s instructions.

(C) Receptacles Mounted on Covers. Receptacles mounted to and supported by a cover shall be held rigidly against the cover by more than one screw or shall be a device assembly or box cover listed and identified for securing by a single screw.

--
Tom Horne

I have a question and it's based upon practicality.

Place yourself in the OP's position. What would your coarse of action be, given the obvious lack of knowledge of the elec. trade practices, that any repair action taken would not be permitted or inspected, ever, and faced with the possibility of having to travel from 1 city block to 50mi, as some posters have, and the inevitability, when you arrived at a vendor, of standing a 50/50 chance you find, either someone of knowledge or a space occupier.

Would you strip the romex, you already had, and pull 2 of the conductors to correct what you perceive as a deficiency, or would you spend the hours of time learning the code and chasing parts?

 

[Eddie_T]

I would fix it and move on. I am sure that I have things that are not up to code as probably do many homeowners.

 

[hornetd]

I have a question and it's based upon practicality.

Place yourself in the OP's position. What would your coarse of action be, given the obvious lack of knowledge of the elec. trade practices, that any repair action taken would not be permitted or inspected, ever, and faced with the possibility of having to travel from 1 city block to 50mi, as some posters have, and the inevitability, when you arrived at a vendor, of standing a 50/50 chance you find, either someone of knowledge or a space occupier.

Would you strip the romex, you already had, and pull 2 of the conductors to correct what you perceive as a deficiency, or would you spend the hours of time learning the code and chasing parts?

I know that I messed up my first suggestion which was to drill the 2 holes, insert 2 8/32 screws, put 2 star washers on them, and tighten 2 8/32 nuts. Done. Any one that cannot do that should never have cracked the box in the first place.

If you install wire that is not listed to be used in conduit and scrape or damage it while doing so then any resultant damage is on you. Your homeowners insurance is what is known as a contract of utmost good faith. That means that both parties undertake specific obligations that they will be held to very closely by the courts. If an insurance company collects premiums on a property while unable to pay a loss to the insured the insurance company executives and it's board members can be convicted of felony fraud and go to prison for a fairly long time which varies by state. If the insured engages in conduct which causes a loss and he new or should have known that the work was unlawful then if he collects he has committed insurance fraud and if the insurer discovers that the loss originated in his unlawful work they get to walk away from the loss. They do not have to pay it. Each party has a strict obligation to tell the other of any circumstance which they become aware of which might prevent the insurer from paying the loss or cause a loss to occur when it can be prevented.

The wire used in an NM cable is not always one of the types that is listed for use in a raceway of which conduit is only one type. It is unlikely to be THHN for instance because that would markedly increase the cost of manufacturing. Lets pull the THHN type designation apart. T is Thermoplastic, HH is very high temperature (90C), N is nylon covered. Why does the manufacturer add the Nylon cover? It's there to make the wire resist damage when being pulled into conduit. If the cable that the conductors are stripped out of is Type NM then the conductors are not listed for High temperature let alone for Very High temperature.

I and several of my fellow firefighters were deposed in a case were a homeowner had done his own wiring and it was source of the "Heat of Ignition". When all the information was in the homeowner had to eat his loss.

Final word on this issue is that if you are not willing to learn and follow the code then you are placing your family's financial welfare and even their lives at risk. There are a fare number of good electrical wiring guides available. It is not that hard to do it right. THHN wire can be ordered on line by the foot and brought to the OP by USPS, UPS...

 

[Snoonyb]

Remember, the question was based upon practicality.
And the subject, the OP, was a relative novice.

So, discounting that the time of the average homeowner/DIY conducting the research has become valueless and UPS/FEDEX is free in your area.

How long would an 1800 watt fixture, powered via 1 or 2 NM #14 conductors, in 1/2" EMT have to continuously operate, to exceed the heat load, melt the insulation, cause a fire and not trip the breaker?

 

[hornetd]

Remember, the question was based upon practicality.
And the subject, the OP, was a relative novice.

So, discounting that the time of the average homeowner/DIY conducting the research has become valueless and UPS/FEDEX is free in your area.

How long would an 1800 watt fixture, powered via 1 or 2 NM #14 conductors, in 1/2" EMT have to continuously operate, to exceed the heat load, melt the insulation, cause a fire and not trip the breaker?

You are really determined to discredit any answer that does not agree with your "the code doesn't matter" approach.

No one can answer that question without a laboratory analysis of all of the factors present which we cannot know. Insulation does not fail from constant overheating in a single second with the neat opening of the Over Current Protective Device (OCPD). The insulation fails gradually by subsiding away from some point of physical pressure as it softens and in many cases arcing will occur at a relatively low level of current flow but a very high level of heat generated. The breaker only has a slight increase in current flow but certainly not enough to trip it. The vast majority of Electrical Fires begin as an arcing fault to ground. Those arcs would not have kindled those fires if the current flowing exceeded the trip point of the OCPD that was protecting those conductors.

All my adult life I have been an electrician. That was my bread work. It is how I paid my bills and supported my family. All of that same period I was a volunteer firefighter in a busy urban station. As just one firefighter I have responded to DOZENS of "Fires of Electrical Origin" during my 35 years of firefighting. I have carried the dead out of several of those fires. I think I can say, with some certainty, that none of the people that did those hack jobs set out to burn anything down or kill anybody. They simply had not taken the time to learn what they were doing and to acquire the right materials for the job.

To me taking short cuts like the one you are advocating is much the same as the person who parked 5 feet away from a fire hydrant instead of the 15 feet that is required by law. They were "only going to be a minute." The 6 inch intake hose was charged with water and jammed itself under a wheel of the car so as to crimp itself shut. The Hose line we were using to support a rescue discharges 150 Gallons a Minute. The tank on the engine holds ~5 minutes of water at that rate of flow. The nozzle team had to hold the stairs or the trapped children and the firefighters who were searching for them would burn alive. My task was utility control and I had just finished it when the apparatus operator yelled "Get Out Boys Get Out. The 2 person search crew made it out onto the front porch roof with both children and the nozzle crew began to bail out because their line had gone dry. Without water to hold the heat down the living room next to the stairs flashed over. [Flash Over occurs when the heat in the involved compartment rises to the point that everything in that compartment that was not yet on fire ignites simultaneously because the compartment has absorbed all the heat it can hold] The resultant blowtorch of heat out into the hallway burned a man who is a Career Firefighter; that means that firefighting is his bread work; from the top of his head all the way down to his buttock on his right side. That is all burn scars now. The county found him work in the code enforcement section of the fire marshals office so he doesn't have to support his family on half pay.

Yes it is further to go to get to the supply house or the home center. Yes it is inconvenient to go to the government office that issues electrical permits and take an open book homeowners electrical permit exam. Yes it cost money to pay the permit fee which covers the cost of the Master Electrician that has the additional training in code enforcement to come out and check your work. But that inspection does provide a bombproof defense against any attempt by the insurer to walk away from the loss. Yes it may cost as much as $10 to ship that cut wire in a padded envelope. It is all more trouble and effort than doing it hack using materials that may or may not be suitable. How much is his; the OPs: home worth to him? How much are the lives of his family worth to him? So you keep pushing that just do it technique. As it happens you will never have to carry out the dead as I have. I believe that any chance of causing the kind of grief I have personally seen is too much.

--
Tom Horne

No we aren't no thin blue heroes and yet we aren't no blackguards to. We're just working men and women most remarkable like you. (with apologies to Rudyard Kipling)

 

[Eddie_T]

A neighbor built a flue and installed a Poppa Bear wood stove. The flue got too hot and set his house on fire, insurance paid.