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Old 02-25-2007, 07:09 AM   #1
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Wiring in older house ?


Greetings--

Most of the wiring in my older house is the 2 wire type (black/white- no ground). The previous owners added several receptacles in the converted garage/laundry room.

These have 3-wire connections. In the pannel, the ground is connected to the same bus (is that the right word here?) as the white (neutral). Is this OK ? OR Does the ground wire need to be connected somewhere else in the pannel ?

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Old 02-25-2007, 09:13 AM   #2
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Wiring in older house ?


The "garage/laundry room" leads me to believe the garage is attached to the house. If so, read on from here...if not, skip to the bottom.

Is the panel you mention a sub-panel or the main panel to the house? If it's the main, then the ground and nuetral should be bonded. In a sub-panel they should be seperated. If it is a sub and they're not seperated, get a ground kit and add it in.

If the garage is seperated,even if the panel comes from the main and is technically a sub-panel, it SHOULD have it's own ground rods outside the garage and the nuetral and ground would again be bonded.

If the wiring past the panel though is only 2-wire, then all this is a moot point because your receptacles have no grounding regardless. Jumping the nuetral around to the ground screw does NOT constitute proper grounding, by the way.


Last edited by jproffer; 02-25-2007 at 09:16 AM.
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Old 02-25-2007, 02:26 PM   #3
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Wiring in older house ?


There is only 1 pannel on the property-- the main feed with the meter.

The previous owners ran 3 wire to the garage/laundry room remodel and to a couple of other "new" outlets in the living room.

All of the outlets in the house are "new" with a ground. They replaced all of the old ones with modern square outlets. I havent bothered to check their ground with a tester because most of the wire in the pannel is 2 wire type.

Thanks for the info !!
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Old 02-25-2007, 03:49 PM   #4
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Wiring in older house ?


the grounds and neutrals in the panel are fine.

the three prong recepticles that have no ground are illegal.
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Old 03-10-2007, 10:12 AM   #5
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Wiring in older house ?


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Originally Posted by jwhite View Post
the grounds and neutrals in the panel are fine.

the three prong recepticles that have no ground are illegal.
Here in Chicago, things are typically required to be run in conduit (NM is a no-no). Therein, the raceway system is allowed by the NEC as the grounding means and the attachment of the (listed) receptacle to the (listed) box creates the ground path. If this system is comprised of NM cable with a separate ground wire, it should be attached to the ground screws on the receptacles. If there is no ground wire and the system is based on NM then certainly, the grounding outlet installations are not correct. In the last case, a GFCI receptacle can be installed as the first receptacle in the circuit allowing the legal installation of 3-prong recepts downstream from it without the need for a separate equipment ground conduction. Of course, these receptacles will not have a dedicated equipment ground connection however the GFCI will protect against an instance where there would be current in the EGC (i.e. a ground fault.)

Hope this helps,
Jim
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Old 03-10-2007, 11:13 AM   #6
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Wiring in older house ?


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Here in Chicago, things are typically required to be run in conduit (NM is a no-no).
Hey there, i am curious about your above statement. So is NM a no no across the board. So if i was to build myself a house with a wooden frame and ran NM throughout the house I would get my hands slapped by the inspector and made to do it all over again.

If this is your rules there whats the reason behind that rule. I want to call it a dumb rule but there has to be a reason somewhere.

Darren
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Old 03-10-2007, 12:35 PM   #7
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Wiring in older house ?


NM is only (that I know of, and that is pretty well known) outlawed in Chicago (conduit-ville ), IL. It doesn't hurt to check with your local AHJ, but I would guess your hands would be fine.
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Old 03-10-2007, 01:32 PM   #8
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Wiring in older house ?


NM is not only outlaw in Chicago, but also in parts of New York City. if I am correct.

Since the National Electrical Code is not a law but a standard, written by a private company, and the local state or county can adopt or not any or all of the NEC, I suggest you find out from your local buiding dept what they prefer to use.

I reciently fell apon a page that claimed that the use of condit only has had a big effect on the number of electrical related fires. I dont know if it is true, I just know that we need to follow the code where we live.
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Old 03-10-2007, 10:09 PM   #9
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Wiring in older house ?


That's why I said "that I know of" ...It's probably because I live in IL.
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Old 03-11-2007, 07:20 AM   #10
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Wiring in older house ?


Quote:
If it's the main, then the ground and nuetral should be bonded.
Since they are bonded, why is it the equipment ground bus says 'equipment ground only'?

Quote:
Jumping the nuetral around to the ground screw does NOT constitute proper grounding, by the way.
Years ago someone told me an inspector told them they could do this. I have never done it , by the way. But if ground and nuetral are bonded/married in the panel, I am not sure why it is wrong. Something to do with path of least resistance in case of a short?
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Old 03-11-2007, 07:55 AM   #11
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Since they are bonded, why is it the equipment ground bus says 'equipment ground only'?
It does not always say that.

Quote:
Years ago someone told me an inspector told them they could do this. I have never done it , by the way. But if ground and nuetral are bonded/married in the panel, I am not sure why it is wrong. Something to do with path of least resistance in case of a short?
The purpose of bonding the grounding electrode system to the neutral at the main panel is to provde a degree of protection against objectional currents. (say from electrical storms) And to insure a low resistance path for current to flow back to the transformer in the event of a line to ground fault.

Current does not take the path of least resistance. It takes all available paths, and shares them based on resistance. Electrical current is deadly because, even though the path through the human may have a very high resistance, the ammount of current it takes to kill someone is minimal.

If we look at a simple electrical circuit we can understand why we do not want to bond the ground to neutral at any other place than where it is required by code for safety.

Lets examine a circuit with one hot, one neutral, and one ground. Under normal conditions the hot is carrying current to a device and the neutral is allowing a return path back to the transformer. The ground is connected to the device box, ground prong, outer metal casing of equipment and such, just sitting there waiting in case it is needed.

If the neutral were to become open between the device and the panel, the device would quit working. The hot side of the device would still be live, but the user would examine the problem or call somone to come look at the probem.

If the ground and neutral were bonded at the device and the neutral were to come open, then the ground wire (which is bonded to the metal case of the appliance, the device box and etc) would now be a current carrying conductor. It would be carrying current back to the panel but the user would have no idea that there was a fault. Touching any part of this now live grounding system would allow the current to share you as part of the return path.

Again it takes very little current to kill a person. So, while the resistance of the path between you and the transformer would be very high, under the wrong set of conditions this situation could be deadly.

The same deadly situation could happen if the neutral were to open between the main panel and the transformer, but the added safety of having the bond at the main panel outweighs the risk of it being there. In addition, when the main neutral fails, there are usually several indications in the system that will cause a user to examine the problem, or call someone. (lights get dimmer and brighter, things only work when the oven is on etc.)
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Old 03-11-2007, 11:56 AM   #12
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Wiring in older house ?


Quote:
Originally Posted by darren View Post
Hey there, i am curious about your above statement. So is NM a no no across the board. So if i was to build myself a house with a wooden frame and ran NM throughout the house I would get my hands slapped by the inspector and made to do it all over again.

If this is your rules there whats the reason behind that rule. I want to call it a dumb rule but there has to be a reason somewhere.

Darren
Darren-

Yes, you'd get slapped pretty hard! And boy, that would be a lot of rework.

I will preface my response to your second question by saying that what I write is not intended to be a shot at the IBEW or unionized labor in general. There are pro's and con's to unions and that discussion would be better conducted over a bar room table. My opinion: NM is not allowed because it is too easy for most Joe-Homeowners to install themselves whereas installing a metallic raceway system require more skill and experience. This is what I like to call "UNION CODE." In Chicago, the IBEW locals (9, 134) are very strong. Outlawing NM simply serves to guarantee them work. I agree with you wholeheartedly: It is stupid, but unfortunately, it is a reality that I (for one) have to cope with.

Another great Chicago "Union Code:" The use of vitrified clay pipe for connecting residential homes to the city sewer. Why clay? It's brittle, easy to damage on installation, heavy, harder to cut than other materials, harder to join than other materials, susceptible to failure due to settlement/soil heave and plant roots grow through the joints with no problem, requiring frequent visits from the plumber. But hey, it keeps the plumbers busy, right? Again, a dumb requirement to you and me but not if you're in the plumbing trade.

TTFN,
Jimmy

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