Expanding ground to residential rooms

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  #1  
Old 08-10-06, 01:10 AM
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Expanding ground to residential rooms

Ive got a couple Gfci outlets in my 1930's home that are properly grounded. They are run back to terminal in service panel.
I would like to replace old two-prong outlets in a few bedrroms with grounded ones and run them to panel as well. They are currently not grounded.
Cable in each box is four wire: (two white, two black). N and H
Actual wire is not braided, think it is either copper or alum. wrapped in black cloth-like material.
I have heard some differing opinions on this matter:

Do I need to use the same type of cable currently in box for my grounds?
If not, what kind of cable can I substitute and can I use it for just ground or do I need to rewire all with same type.
And does my ground run need to be same gauge or smaller?

As a bounus Q, anyone want to take a guess as to what kind of cable my home was wired with?

Thanks in advance--DIY rocks
 
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  #2  
Old 08-10-06, 02:40 AM
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Old wire was cloth romex. You need new romex.
Size depends on the size of the breaker you want to re-use.
 
  #3  
Old 08-10-06, 05:31 AM
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Your existing wiring sounds like the earlier versions of NM (non-metallic) wire. Two conductors, no ground.

To provide a ground you have two choices. Replace the existing cable all the way back to the main panel or add a ground.

To replace the cable you need new NM cable, assuming that NM is allowed in your area, or you need individual conductors in conduit. The wire needs to be 14 gage for 15 amp circuits or 12 gage for 20 amp circuits.

To add a ground wire it must be the same size as the existing wire, either 14 or 12 gage, and it needs to run back to the main panel and connect to the ground buss.
 
  #4  
Old 08-17-06, 07:22 PM
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Thanks for the inormative responses.
I think it is old NM cable as well.

So I am going for the option of just adding a ground (12 g) to the existing four-wire system and daisy-chaining ground from 1st outlet to 2nd outlet in room.

Tell me if this sounds right:
Service panel ground bus>>>wire nut>>>split 2 ways>>>one to green terminal on receptacle 1>>>one to terminal on receptacle 2.

Do I need to connect ground to metal box of receptacles as well?
If so how?

So I will have my outlets grounded and I can use my plug in gurge protectors, great. Now I read this article:
http://www.dslreports.com/faq/10431
...that says plug in surge protectors are a compromise at best and might even damage the equipment I am trying to protect!!

It goes on to recommend a UPS or LAN proection system. I am just trying to find the least expensive way to ADAQUETLY protect my computer and equipment.

If I have to buy an expensive UPS in addition to grounding my outlets, shouldn't I just buy an expensive surge protection device that dosen't need a ground to operate well?

I think I speak for a lot of folks out there when I say: What the heck?
 
  #5  
Old 08-17-06, 07:44 PM
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If you are most concerned with the computer/electronics,Ground that outlet and go with a surge supp. strip.
Other outlets can be protected by GFCIs'.
To me, run a ground to each outlet... Just add some time ($) to the project and rewire.
 
  #6  
Old 08-17-06, 08:00 PM
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Statistically speaking your chances of being hit by a surge that will damage your equipment is pretty low, BUT if it does happen it can be mighty expensive.

A UPS is good but not necessarily required. A PROPERLY grounded outlet is absolutely necessary for proper surge suppression, even when using a UPS.

Yes, the metal receptacle box also needs to be grounded. You will either need to drill and tap a threaded hole to receive a grounding screw with grounding pigtail OR you may use a "grounding clip" if your ground wire is solid and not stranded wire.

I may be wrong (I know someone will correct me) but I think that the grounding wire needs to be run with the power wires. I do not think that a "separate" grounding conductor that is added after the main wiring is acceptable.

Also, since you mentioned bedrooms, this could be interpreted as "remodeling an electrical application" by your LOCAL inspection authority and that Authority may REQUIRE that you upgrade that particular (bedroom) wiring to Arc Fault Current Interruption (AFCI) circuit breakers.
 
  #7  
Old 08-17-06, 08:10 PM
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Based on prior discussions of running ground wires, many on this forum (me included) would recommend running new NM cable to these receptacles, thus updating the wiring and adding a ground at the same time. The hardest part of the project is fishing the wire up through the walls into the boxes, as long as you're going to put yourself through it, you might as well replace the whole cable. An overall cleaner install in my opinion.

As for UPS versus surge suppression - my understanding is that the surge protection between a high quality suppressor is equivalent to that of a UPS. The UPS helps additionally by allowing your computer, Tivo, whatever shut down gracefully as opposed to just being "unplugged". (feel free to correct me if I'm wrong)
 
  #8  
Old 08-17-06, 08:20 PM
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in addition

Running new cable shouldn't be that much of a hassle provided you have a crawl space under your house. I have to agree to just about everything else...assuming NM is allowed in your area i would just rerun the entire circuit from the main panel.

As for the UPS vs. surge supp. I prefer UPS because not only does the unit protect your line voltage equip but also has allowances for cable/network/and phone all of which pose a possible threat to sensitive PC equip. (the specific unit i speak of was purchased 4 years ago for 79.99 (not to pricey comparatively)

let us know if this is helpful and how else we can help you
 
  #9  
Old 08-17-06, 08:45 PM
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You are well within code to run a 12 gage insulated ground wire to each receptacle you wish to ground. Ground both the receptacle and the metal box. Use a pigtail in the box and connect to the ground screw in the back of the box (you probably have to supply the screw).

I have all my computers on UPSes so that I don't lose anything if the power goes out and so I have time to properly shut down. I have all my televisions and other electronics on good quality surge suppressors (read: NOT inexpensive outlet strips that offer mediocre at best surge suppression).
 
  #10  
Old 08-17-06, 08:55 PM
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Is my assumption correct?

UPS= Uniterupted power supply, offering battery back up for a short period, and no power conditioning. Typicaly used for time to shut down equipment or a generator to start.

As opposed to a power conditioner wich will regulate the incoming voltage, including surges and dips, some are available with a battery back up.
 
  #11  
Old 08-18-06, 02:39 AM
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The term "UPS" is often used for both, even by the mfg. Yes, some condition power, some just back it up for a short time. Check the product specs. Some also offer internal surge protection for the outlets, and for the phone or catv line.
 
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