Using existing EGC as Neutral...

[1793]

I sent out a few PMs on this subject and it was thought that the folks on the forum would be interested and helpful so here we go.

Wiring method is NM.

The electrician mistakenly took out the original feed to the Garage and to "fix" his mistake he took and existing 3 wire and reworked the connections to the following: took the red, and connected to the Hot of a lighting circuit to feed the Garage, took the black and used as a switch loop to a light and finally he took the white and tied it to the grounds in the switch box in order to get a Neutral for the Garage circuit.

My concern is being able to point out to HO and the GC who hired the electrician who did this the possible hazards associated with this setup.

Thanks to all and I look forward to your help.

 

[Pierre C Belarge]

The "ground", which are equipment grounding conductors do not carry current during normal operation, that is one reason they are permitted to be bare. The EGC are also bonded to all metallic parts back to the 1st service disconnecting means.

The neutral/grounded conductor is a circuit conductor and does carry current during normal conditions - that is why it is called a circuit conductor.

If one is to bond the grounded conductor to the EGCs, then those bare conductors will now have voltage and current flowing on them all the way back to the source. This voltage and current can cause shock, fire, and possibly death.
ALL VERY BAD THINGS!!!

 

[quogueelectric]

The "ground", which are equipment grounding conductors do not carry current during normal operation, that is one reason they are permitted to be bare. The EGC are also bonded to all metallic parts back to the 1st service disconnecting means.

The neutral/grounded conductor is a circuit conductor and does carry current during normal conditions - that is why it is called a circuit conductor.

If one is to bond the grounded conductor to the EGCs, then those bare conductors will now have voltage and current flowing on them all the way back to the source. This voltage and current can cause shock, fire, and possibly death.
ALL VERY BAD THINGS!!!

I think Pierre covered all of the basics so I concurr with this statement.

 

[mcclary's electrical]

The "ground", which are equipment grounding conductors do not carry current during normal operation, that is one reason they are permitted to be bare. The EGC are also bonded to all metallic parts back to the 1st service disconnecting means.

The neutral/grounded conductor is a circuit conductor and does carry current during normal conditions - that is why it is called a circuit conductor.

If one is to bond the grounded conductor to the EGCs, then those bare conductors will now have voltage and current flowing on them all the way back to the source. This voltage and current can cause shock, fire, and possibly death.
ALL VERY BAD THINGS!!!

no voltage pierre.......just current. I agree with you, but just current

 

[iwire]

no voltage pierre.......just current. I agree with you, but just current

It is imposable to have current without voltage.

 

[chris kennedy]

Norb, you have violations of 250.24(A)(5) and 250.142(B). Here is the NECHB commentary that follows 142(B). (aka, what Pierre said)

One major reason the grounded circuit conductor is not permitted to be grounded on the load side of the service [except as permitted in 250.30, 250.32(B) exception, and the four exceptions to 250.142(B)] is that, should the grounded service conductor become disconnected at any point on the line side of the ground, the equipment grounding conductor and all conductive parts connected to it would carry the neutral current, raising the potential to ground of exposed metal parts not normally intended to carry current. This could result in arcing in concealed spaces and could pose a severe shock hazard, particularly if the path is inadvertently opened by a person servicing or repairing piping or ductwork.

Even without an open grounded conductor (usually referred to as an open neutral), the equipment grounding conductor path would become a parallel path with the grounded conductor, and there would be some potential drop on exposed and concealed dead metal parts. The magnitude of this potential difference would be determined by the relative impedances of the equipment grounding path and the grounded conductor circuits. Not only would the equipment grounding conductor path be affected, but all parallel paths not intended as equipment grounding conductors would be affected as well. This could involve current through metal building structures, piping, and ducts. The requirements of 250.30 and 250.32(B) have been revised in recent editions of the Code to prohibit the creation of parallel paths for normal neutral current.

As for your 2nd question via PM, interconnection of smokes is required by NFPA 101 section 9.6.2.10.3. I only gave this link a quick read, maybe you can find more. Good luck.

 

[1793]

The "ground", which are equipment grounding conductors do not carry current during normal operation, that is one reason they are permitted to be bare. The EGC are also bonded to all metallic parts back to the 1st service disconnecting means.

The neutral/grounded conductor is a circuit conductor and does carry current during normal conditions - that is why it is called a circuit conductor.

If one is to bond the grounded conductor to the EGCs, then those bare conductors will now have voltage and current flowing on them all the way back to the source. This voltage and current can cause shock, fire, and possibly death.
ALL VERY BAD THINGS!!!

Norb, you have violations of 250.24(A)(5) and 250.142(B). Here is the NECHB commentary that follows 142(B). (aka, what Pierre said)

As for your 2nd question via PM, interconnection of smokes is required by NFPA 101 section 9.6.2.10.3. I only gave this link a quick read, maybe you can find more. Good luck.

Your replies have helped me get a good handle on this situation. The explanation and the Code reference are what I was hoping for.

 

[SEO]

Using the EGC as a neutral caused people to get shocks off ranges and dryers when they touched them. The person was also a return path for the neutral when the appliance was being used. The same thing could happen to all conductive parts bonded to grounds being used as neutrals after the first disconnect.

 

[sparkyway]

I encountered an barn's service feed recently. It was fed with a 12-2 wg uf cable from a mobile home service (white and black wires were to the breakers and the bare ground was his "neutral"). The owner called me explaining he was shocked as he touched the metal building. Long story short, one leg of his 240 feed went bad and the bare ground was tied to everything nearby sending volts and amps to all things metal...dangerous! After a basic explanation similar to Pierre's (well stated by the way), he now has a 4-wire service with a proper isolated neutral. I guarantee the same original wiring situation is all over in these parts...darn shame.

 

[Pierre C Belarge]

no voltage pierre.......just current. I agree with you, but just current

If one use a meter, there would be both voltage and current taken. The amount depends on Ohm's Law. I have actually measured circuit voltage and high current readings on EMT...a scary thought.

 

[1793]

Thought a photo or two would be nice.

 

[romba_one]

Just to add something about the pictures...

I've seen two fires (small) start due to wiring like this. The EGC used as a neutral, along with a poor connection to metal box at a critical point will likely cause some arcing/sparks. I mention this because in those pictures above the EGC pigtail [appears] to be under a mounting screw. IMO it is a violation to start with (even w/out the neutral piggy backing the EGC) as the screw is not listed for the purpose and ground screws are suppose to have no other uses ie mounting.

 

[madpenguin]

Don't know why I let stuff like this get under my skin but it steams me none the less. I just ran into a similar situation last friday. A dedicated (new) 15A homerun to a 2nd floor bathroom GFCI. The grounding conductor was being used as the neutral and the grounded conductor was tied to the receptacle ground... ?

120v between the black and bare but maybe 5-10v between the black and white. They must have snagged the cable on something during the pull and severed the grounded conductor. Or a staple somewhere...

I don't get people sometimes. I really don't....

Told the GC I couldn't hook it back up like that. Still waiting for a home owner response I guess...

 

[iwire]

IMO it is a violation to start with (even w/out the neutral piggy backing the EGC) as the screw is not listed for the purpose

There is no such thing as a 'listed ground screw', even the Green 'grounding screws' that we can buy are not listed, They are not required to be and as far as I know UL has no specification for them to be listed to.

and ground screws are suppose to have no other uses ie mounting.

I agree 100%.

 

[220/221]

Send him the link from last year when a child was electrocuted by touching a garage door.

Ground was apparently used as a neutral and the neutral was somehow opened. The alternative path was thru the gound pin on the GDO, thru the metal to the droor.

Never use a ground as a conductor. If you lose the neutral path back to the source, it will find another route thru anything that is grounded.

 

[sparkyway]

The Isaac Lawrence story from Louisville KY (Isaac's Law) is one for all to know about... well put 220/221.

 

[1793]

The Isaac Lawrence story from Louisville KY (Isaac's Law) is one for all to know about... well put 220/221.

Yup, I know the story and the cause, and ALL of the DIYers should know about it as well.

 

[romba_one]

There is no such thing as a 'listed ground screw', even the Green 'grounding screws' that we can buy are not listed, They are not required to be and as far as I know UL has no specification for them to be listed to.

I agree with your first statement above, but here is what I'm getting at:

That screw does not appear be any one of the connection means stated in 250.8(A)(1-7). I doubt it is "listed" for the how it is used in the pictures above...so I believe the screw in that picture is not going to conform with 250.8(A)(8) which allows for grounding and bonding equipment to be "other listed means". So when I say the screw was not listed for the purpose you have to reference 250.8(A)(8) as 1-7 would not apply. At least that is my logic on this issue.

 

[1793]

Update...

Update...

I spent a good deal of the day today correcting this situation.

As always I appreciate everyones input and comments.

The CG / EC is getting my Invoice form the HO. I have also left with the HO a printout of most of the replies from this thread along with the photos.

 

[TobyD]

I done a repair job on my neighbors house a few years ago and the EGC's were glowing red.This was caused by a local handyman.Luckily the homeowner noticed something wasn't quite right.His explanation was ,I've always done it like that.HMMM.