Converting Non-grounded recepticle to a grounded recepticle

[Anonymous]

Posted by: Robert B Williams
Posted: Tue Jul 30, 2002 8:03 pm

Is it possible to convert a non-grounded recepticle to a grounded recepticle without rewiring? My home was built in about 1970, and all recepticles are non-grounded. I would like to ground them all, if it is feasable. I will need a wiring diagram if this is a possibility. ?:

[Anonymous]

Posted by: Wgoodrich
Posted: Tue Jul 30, 2002 10:20 pm

When you wiish to change a two prong receptacle to a three prong receptacle you have three options as mentioned below.

You may replace the old two prong receptacle with a three prong receptacle without installing an equipment grounding wire as long as that new three prong receptacle is GFI protected with a tag on each receptacle that is protected by that GFI on that same circuit as being GFI protected. The reason for this is although the GFI protective device monitors the receptacle there is no equipment grounding conductor serving that receptacle.

You may replace the old two prong receptacle with a three prong receptacle if you install a single green equipment grounding conductor from that certain replaced receptacle and ran as close to the old existing branch circuit as possible back to the panel grounding bar or the ground rod or the water pipe within 5' of the entry of that metal water pipe into the structure and only if that metal water pipe is in direct contact with the earth for at least 10'. Never connect to a metal water line when that connection is not within 5' of the entry of the building where it is in direct contact with the earht for that 10'.

You may replace that old two prong receptacle with a new branch circuit replacing that old branch circuit with that new branch circuit coming from the panel or another branch circuit that has a good equipment grounding conductor served by that main panel.

In my opinion if you are wanting to replace several two prong receptacles with three prong receptacles then you should consider installing new wiring or use the GFI protective device option. It is illogical to fish a single wire from those receptacles back to the main panel grounding bar. You can fish new romex replacing the circuit as easy or easier in fishing the wires than if you fish a single green conductor back to the panel.

Hope this helps

Wg

[Anonymous]

Will post here assuming not replying to late of a post. Am I correct in assuming we are no longer allowed to connect a 3 pronged receptacle to an existing metal cut in box or 4'sq box, that gets it's mech ground thru the sytem's existing conduit,BX, or greenfield? If so, are we saying all receptacles must be GFI or GFI protected downstream(load side) or just leave existing 2 prong in place? Asside from as mentioned trying to get grnd wire to point of receptacle or running new feeds. Please tell me I'm wrong here and grounded (3 pronge) receptacles legal where grnd present by way of pipei, bx ETC. Understand romex ETC. carries isolated ground,but then again those spliced EGC could be made poorly,loosing ground downstream . Also are the self grounding receptacles still legal? Where no green tap needed to metal box,except in say 4" sq box where cover or ring cold be removed breaking ground. From old school and realize changes with romex. If above fact! is green wire then reqired to be installed in conduit runs. Again tell me I'm wrong in reading, as this would be next to impossible dollar wise to the old homeowner. Hey! thank YOU Hopefully these questions pertain to where no ground is present at all.

[Wgoodrich]

There is a lot and a lot more IFs in answering your questions. I will try and hit the most influential answers as best I can. Please take into account these questions are rather broad in nature and there may be an exception or two that may apply. If you see an answer that you question come back with a reply on that certain answer then we will deal with the details of that certain answer that I provided.

YOU SAID;
Will post here assuming not replying to late of a post.

REPLY;
It is never to late to ask a serious question seeking knowledge.

YOU SAID;
Am I correct in assuming we are no longer allowed to connect a 3 pronged receptacle to an existing metal cut in box or 4'sq box, that gets it's mech ground thru the sytem's existing conduit,BX, or greenfield?

REPLY in three parts;

A metal cut in box is connected to drywall where that drywall is not recognized by the NEC as a coductor or a grounding source. The metal box supported by drywall and without an approved grounding conductor to carry the faulted current is just an isolated box that needs to become grounded by installing an equipment grounding conductor recognized by the NEC.

A 4 square metal box is also the same as mentioned above being an isolated piece of noncurrent carrying metal part that is requried to be grounded by connection to a NEC recognized equipment grounding conductor.

The two mentioned above can not be a grounding path unless these two metal boxes are connected to an approved equipment grounidng conductor. There is an exception in the NEC that forgives a single metal box used in the installation of a branch circuit extension of a two wire branch circuit that is existing without an equipment grounding conductor forgiving the need to bond that certain metal box used as discribed from the requirment of being bonded to a nonexistant grounding conductor while serving an existing two wire branch circuit that is without an equipment grounding condutor with that existing branch circuit.

YOU SAID;
If so, are we saying all receptacles must be GFI or GFI protected downstream(load side) or just leave existing 2 prong in place?

REPLY;
What the NEC is saying is that if you have a two prong receptacle being served by a two wire branch circuit that is without an equipment grounding conductor with that circuit and installed during a time that the NEC accepted that wiring style to meet the NEC rules at the time of installation then forever it be controlled and ruled as unchanged and ruled by that original version of hte NEC at the time of original installation.

If you change that old receptacle due to ill repair or due to bad looks your are allowed to replace that two prong receptacle with a new two prong receptacle.

If you change that two prong receptacle with a three prong receptacle then you must connect that new three prong receptacle with a recongnized grounding conductor by replacing that two wire branch circuit with a new three wire branch circuit that has an NEC recognized equipment grounding conductor or provide GFI protection to serve as an accepted alternative to the missing equipment grounding conductor.

YOU SAID;
Asside from as mentioned trying to get grnd wire to point of receptacle or running new feeds. Please tell me I'm wrong here and grounded (3 pronge) receptacles legal where grnd present by way of pipei, bx ETC.

REPLY;
While flexible metallic conduit in size 1/2" inside dimension or larger, or EMT, or Rigid, or IMC is a recognized equipment grounding conductor, BX is not nor ever was a recognized grounding conductor. BX is a generic name of older manufactured cable that had the wire installed during manufacturing process and protected by a 3/8" inside demension flexible metallic spiral tape type sheild. Nowhere in the NEC ever did it approve any flexible metallic sheathing or conduit that is sized less than 1/2" inside diameter to be used as an equipment grounding conductor in lengths longer than 6 feet in length. You old or new BX cable [generic term] is not approved by itself to be an equipment grounding conductor in lengths exceeding 6 feet long. There is an exception in what is called AC cable that is allowed to use the 3/8" inside demension manufactured with the wires in it to be used as an equipment grounding conductor but only if this A/C cable has an aluminum metallic strip installed during manufacturing process and listed and labeled for use and equipment grounding conductor and again only if the metal strip is inside the A/C cable the entire length of that manufactured cable. Even metal clad cable has an equipment grounding conductor in it. Metal clad cable is the replacement of the older BX cable. There was later in the life of the older BX cable at the last of the life experience of the older BX cable a design of the older BX cable that had a small approximate 18 awg bare wire in it. This style BX cable was allowed and still is allowed to be used as an equipment grounding path but only if it has that bare wire in its cable the entire length and only as existing not new installations.

YOU SAID;
Understand romex ETC. carries isolated ground,but then again those spliced EGC could be made poorly,loosing ground downstream .

REPLY;
You are correct in saying that conduit such as EMT connected by set screw connectors etc. have been known to separate breaking the equipment grounding path. These breaks should be repaired as normal maintenance yet often found in the field still broken. Also understand that if you use a 3/8" inside diameter flexible conduit or sheathing you are asking that when a fault occurs for sparks to emmit from the entire length of that 3/8" inside diameter flexible conduit or sheathing creating a major fire hazard. Using 3/8" flexible conduit or sheathing in lengths exceeding 6 feet long is actually making things worse than if you didn't have an equipment grounding conductor at all. The 3/8" flexible metallic conduit or sheathing has been tested and has been proven inadequate to contain a faulted current without the metal strip installed within the flexible conduit or sheathing the entire length of that manufactured cable. Never has the NEC recognized 3/8" in flexible anything to be an approved equipment grounding conductor ever in the NEC. Many have tried to twist wording etc. to convince people to use this 3/8" as an easy way out from a proper equipment grounding conductor, but in doing so they are making things worse creating a major fire hazard during a faulted current cycle more dangerous than they can imagine.

YOU SAID;
Also are the self grounding receptacles still legal? Where no green tap needed to metal box,except in say 4" sq box where cover or ring cold be removed breaking ground.

REPLY;
A self grounding receptacle is only approved now or ever in the past to bond that receptacle to the steel box that is with an approved equipment grounding conductor and properly grounded, or to bond that steel box to a receptacle that is with an approved equipment grounding conductor that properly grouded that receptacle. A self grounding receptacle is only a normal receptacle with a sping clip recognized by testing labratories to create a grounding path between the receptacle and steel box. This self grounidng receptacle is not magic and can not create a grounding path back to the main service rated panel through the wood studs or through the air. Either that steel box or that receptalce must be connected to an approved and NEC recognized equipment grounding conductor that is properly connected to the main service rated panel in an approved path.

YOU SAID;
From old school and realize changes with romex. If above fact! is green wire then reqired to be installed in conduit runs.

REPLY;

Romex changes nothing from the past. An accepted grounding conductor recognized by the NEC is listed in the NEC and each grounding conductor recognized has in the NEC its own rules of installation while using that product as an equipment grounding conductor. Check NEC 250.118 for a list of recognized equipment grounding conductors. The refer to that certain product's rules of installation in the NEC that limits its use and installation minimums to be used as the equipment grounding conductor. Notice in each product's installation rules concerning flexible that 1/2" [inside dimensions as required to be measured in electrical product] or larger is required to be used as an equipment grounding conductor. 3/8" [again inside dimensions measured as required for all electrical conduits etc.] is limited in length of 6 feet in all catogories of flexible metallic conduit or tubing unless with an equipment grounding conductor or a metal tape inside the manufactured product the entire length of that product. See each rule you will see the 6 foot length limitation for 3/8" ID flexible metallic conduit or tubing.

YOU SAID;
Again tell me I'm wrong in reading, as this would be next to impossible dollar wise to the old homeowner. Hey! thank YOU Hopefully these questions pertain to where no ground is present at all.

REPLY;

You choices are when dealing with existing two wire branch circuits is to leave it untouched as existing or if extending that existing two wire branch circuit or changing from a two prong receptacle to the three prong receptale then you must, add GFI protection without connecting any equipment grounding conductors from that two wire branch circuit, or run a single green insulated equipment grounding conductor from that extension or replaced to three prong receptacle directly ran as close as practicable with the old existing circuit back to the main service rated panel or to the grounding electrode or grounding electrode conductor within 5 feet of where that grounidng electrode enters the dwelling, or replace the old two wire wiring with a new three wire branch circuit.

Hope this helps

Wg

[Anonymous]

TY for reply! Understand what is expected when dealing with grnd outlets. How is one to tell if that alluminum strip is in cable? after installation its no longer visible,when inside connector and behind wall. The real old Bx (opp's) mcc usually had rh wire and had genrally a double spiral wrap of metal sheating along with a cotton or fiber wrap! Weighed a ton. Newer version then had metal strip along with TW wire. Again in installing numerus times that strip was cut off or broken off before installing in connector. Would I assume correctly, then that broke the EGC capacity of that cable.? Also the plastic(anti short) protector placed inbetween cable and wire also "could" have broken path. Anyway I know like you said there are many IF'S, commonsence goe's along way in the electrical field!! What,s worse getting electrocuted from grounded out drill,plugged into an ungrouded plug VS the chance a fire starting due to a fault on line with bad ground! NEC can only assure what they find and recomend with requirement's. The guy that cut's his third prong off his extension cord because he's to lazy to get an adapter(installed right) or three wire extension cord. Maybe should get a shock. But then again if the 2 pronge receptacle has no ground the little forkue on adapter put under plate screw serves no purpose other than ability to use plug. Hey where doe's it end, maybe in my Great Grand kids era things will be all perfect. Don't mean to chew your arm off but when retired you have little to do but talk and ask dumb questions. Found a penny one day behind a fuse and spent an hour explaning reason why shouln't be there upon finishing, guy siad yes but I've never blown a fuse! "Common Scence". Tanks for your time

[Wgoodrich]

You will only find the aluminum strip inside flexible metallic cable that is listed and labeled as type A/C cable. A/C cable with the aluminum strip augmenting the flex as a grounding path as requried today did not exist back when the older BX cable was being installed. Type A/C cable appeared with the aluminum strip around the same time metal clad with the green equipment grounding conductor installed in the cable during manufacturing process replaced the older BX cable with the smaller bare equipment grounding conductor installed during the manufacturing process that replaced the older two wire BX cable that never was approved with any sort of equipment grounding available.

Now to explain the installation of the red plastic bushing in the type A/C and metal clad cables. The aluminum strip inside the cable is allowed to be cut even with the metal sheathing of the type A/C cable. The metal sheathing is connected by an approved type A/C cable connector to a steel box the aluminum strip takes over as an augmenting of the metallic sheathing at the begining of the metal sheating. There is no connection required of the aluminum strip to anything but just the contact within the metal sheathing the length of the metal sheathing. The intent is to stop the emmision of sparks during a fault occurence allowing the aluminum strip to assist the current to jump from wrap to wrap of the metal flexible sheathing preventing the meltdown of loose wrapping experienced in 3/8" ID flexible metallic sheathing. The aluminum strip assists the faulted current to jump from wrap to wrap thus stopping the emissions of the sparks that occur on a 3/8" ID flex cable longer than 6 feet in length that is without the aluminum strip. The aluminum strip will still be visible if you slide of the red plastic bushing. You will find a slit in the red plastic bushing to allow its removal for inspection and confirmation that this aluminum strip is there. You will not find the aluminum strip inside any manufactured metallic flex cable that has insulation on the conductors that is not plastic insulated wires. If you find the paper style insulation on the wires you have old two wire paper insulated BX cable not approved for use as an equipment grounding conductor.

The red bushing is installed to protect the sharp edge of the metallic sheathing from cutting into the insulated conductors. Again you will not find the red plastic bushing on older paper insulated two wire BX cable that is not approved for use as an equipment grounding conductor.

Hope this helps

Wg

[Anonymous]

Got it ! Thank you