[Tom_2010]

I recently bought a house with 2-wire throughout, 2-wire without grounding conductor. Home has a circuit breaker box, 100 amp service.
This is a brick ranch on a slab, with the electrical service grounded only to the plumbing.

I don't have an immediate need to replace all of the wiring in the house with updated electrical wiring. However, I think it makes good sense to do something before hooking up a room full of desktop computers.

Without knowing much, here is what I think I understand thus far (Confirmation of below is much appreciated, or argue me down! See also my questions, please.)

(1) I've been told that all I need to do is replace all the outlets with GFCI.
(a) Q: If there is no grounding conductor on a 2-wire, what is the risk of doing only this action in item 1 ?
(b) What about places which have a terminally active point, but no 'outlet' - such as an attic fan which is on the electrical circuit but which
doesn't have a receptacle outlet? What is the risk at those points?

(2) Obviously I could have someone fish the entire house and replace all wiring with new wiring, in addition. I would do solution item 1 and solution
item 2 together, in this case. But is there more that would also need to be done? What about behind the panel, meaning between the panel
and the outside meter, which I understand is also older wiring?

(c) What else should I be thinking of here, that I obviously do not understand or am not considering?

I really appreciate advice!

Tks.

 

[Wildie]

I recently bought a house with 2-wire throughout, 2-wire without grounding conductor. Home has a circuit breaker box, 100 amp service.
This is a brick ranch on a slab, with the electrical service grounded only to the plumbing.

I don't have an immediate need to replace all of the wiring in the house with updated electrical wiring. However, I think it makes good sense to do something before hooking up a room full of desktop computers.

Without knowing much, here is what I think I understand thus far (Confirmation of below is much appreciated, or argue me down! See also my questions, please.)

(1) I've been told that all I need to do is replace all the outlets with GFCI.
(a) Q: If there is no grounding conductor on a 2-wire, what is the risk of doing only this action in item 1 ?
(b) What about places which have a terminally active point, but no 'outlet' - such as an attic fan which is on the electrical circuit but which
doesn't have a receptacle outlet? What is the risk at those points?

(2) Obviously I could have someone fish the entire house and replace all wiring with new wiring, in addition. I would do solution item 1 and solution
item 2 together, in this case. But is there more that would also need to be done? What about behind the panel, meaning between the panel
and the outside meter, which I understand is also older wiring?

(c) What else should I be thinking of here, that I obviously do not understand or am not considering?

I really appreciate advice!

Tks.

Its not necessary to replace ALL the recepts. with GFCI. Only the first one in the string. This will protect standard recepts. that are wired down stream from it!

 

[Tom_2010]

Wildie wrote . . .

Its not necessary to replace ALL the recepts. with GFCI. Only the first one in the string. This will protect standard recepts. that are wired down stream from it!

I had been told this by a house inspector before buying the house. I don't know for sure where the first receptacle is on the circuit, but was told by the previous home owner that it is in the attic.

So, I could have someone nail down the string for me and replace the first one with GFCI. However, I'm concerned that computer equipment won't be properly protected. As an example, AT&T came out to install U-Verse in the bedroom where the computers will eventually be going. (Right now, that bedroom contains only their AT&T modem.) That room didn't have GFCI, and he said he wasn't really supposed to install where there weren't GFCIs. However, he did something to the receptacle (adding some sort of short, I imagine) and went ahead and did the install, but told me that the house (and future equipment) was really susceptible until adding proper modern system grounding (and replacing wiring).

 

[brric]

There is no reason to install GFCI receps for computers. If you think your equipment requires equipment grounds, using GFCIs will not provide grounding on a two-wire circuit.

 

[Tom_2010]

brric wrote:
... using GFCIs will not provide grounding on a two-wire circuit.

Thanks. That's what I thought, given that there was no grounding conductor at all in my current 2-wire. I am going to look, then, into having the first receptacle on the house's circuitry replaced with GFCI and additionally, running updated wiring to at least the receptacles of the room where this equipment will be placed (as well as whatever working-backwards wiring related to that bedroom needs to also be done.)

Thank you.

 

[Scuba_Dave]

As an example, AT&T came out to install U-Verse in the bedroom where the computers will eventually be going. (Right now, that bedroom contains only their AT&T modem.) That room didn't have GFCI, and he said he wasn't really supposed to install where there weren't GFCIs. However, he did something to the receptacle (adding some sort of short, I imagine) and went ahead and did the install, but told me that the house (and future equipment) was really susceptible until adding proper modern system grounding (and replacing wiring).

That's bull...I've never had any of my equipment installed on a GFCI outlet
So...unless you told him there wasn't a ground I can't see why they were looking for a GFCI
As stated GFCI doesn't provide a ground in any way

I sure hope he didn't install a Bootleg ground
IE - connecting ground of an outlet to neutral...or neutral to metal box or some such thing
Find out what they did & post results

Under NEC 2008 bedrooms need to be AFCI protected, not GFCI

 

[Klawman]

Under NEC 2008 bedrooms need to be AFCI protected, not GFCI

Doesn't the 2008 NEC essentially require the entire dwelling to be AFCI, whereas the 2005 only required bedrooms?

 

[bobelectric]

G.F.C.I. receptacles have varistors built in for surge protection.I've seen where they where they saved modems and appliances from surges caused by high voltage conductors contacting distribution wires. I'm not sure how they react without a third,(grounding) conductor.

 

[brric]

G.F.C.I. receptacles have varistors built in for surge protection.I've seen where they where they saved modems and appliances from surges caused by high voltage conductors contacting distribution wires. I'm not sure how they react without a third,(grounding) conductor.

Could you provide some documentation for this assertion?

 

[bobelectric]

www.electrical-forensics.com voltage surge suppressor fires

 

[Tom_2010]

bobelectric,
The URL above needs to be edited to correct a missing letter, but it works when corrected:
http://www.electrical-forensics.com/

 

[brric]

There is no evidence in that link of any equipment being protected by the GFCI. Quite to the contrary it gives evidence of destroyed equipment.

 

[bobelectric]

Thank,tom. Took care of it.

brric,I'm going on personal experience of incidents I've responded to and seen.

 

[Tom_2010]

Hopefully you can all agree that the first outlet in the circuit should be replaced with GFCI. Or, if that first circuit does not have an actual receptacle on that circuit, that a receptacle should be added on that circuit and it should be GFCI.

I have appreciated the help and insights and will now start to call some people to come out and take a look at the situation of the house.

 

[AllanJ]

GFCI is to protect people.

(copied from another thread)
Electronic equipment should be grounded with or without GFCI. Take a long say #14 wire, strip of bare spots as needed, and screw it to each piece of equipment in turn where the screw contacts the chassis or metal part of the cabinet which in turn contacts the chassis. Connect the far end of the wire to a known ground.

Alternative, plug the equipment (items with 3 prong plugs) into 3 to 2 prong adapters where the ground lug or pigtail is connected to a wire (similar to the above) connected to a known ground.

As time and convenience permit, you can rewire the receptacles a few at a time with new Romex cables.

Since I hate fishing, I would feel free to run ground wires on the wall surface, from each receptacle say down to the baseboard and up and around doorways and down to the panel if needed and more or less approximating the route of the power feed for the respective outlets down to the panel, a slightly more formal version of the previous ground wire I described. During a future remodeling project, new Romex run through the wall can replace both the internal two conductor (BX?) and external ground.

 

[Scuba_Dave]

All depends upon what you want
A GFCI will give you GFCI protection, nothing more
It will not provide any kind of ground path

If at all possible I would run a circuit for the computer equipment
But there are probably plenty of houses with 2 wire circuits & PC's running

 

[Daniel Holzman]

The purpose of an independent equipment ground is to protect people from shock in the event that the metal casing of a piece of equipment becomes energized. This is quite different than the purpose of a GFCI or AFCI. As previously noted, a GFCI on an ungrounded circuit will not provide an independent equipment ground, however it will shut off the circuit in the event that there is more than a 5 milliamp difference in current between the hot wire and the neutral. This situation would occur in the event the hot wire was in contact with the case, and the circuit was operating.

However, if the hot wire touched the metal box, and the circuit was not energized, i.e. nothing was plugged in, I don't think the GFCI would trip (perhaps an electrician confirm this or correct it). As I understand it, that is the purpose of the independent equipment ground (IEG), if the box becomes energized, the IEG creates a safe path for fault current to reach the main ground at the panel. The GFCI does not provide this.

I had the same situation at my house, lots of two wire circuits with no IEG. I replaced the circuits that had no IEG with new wiring, and replaced the second floor panel with a panel that had a separate IEG bar. Lots of work, but I hope it added some safety to the system.

As for computer equipment, if you are concerned about surges, get a surge protector. If you are really concerned, spring for a battery backup system with integrated surge protection. Either one will do more to protect your computer system than adding a ground. The ground is for your protection, not the equipment.

 

[Scuba_Dave]

Good point, I have always had my computer on a UPS

I also have a UPS on my TV
It was actually free after rebate

 

[brric]

Do not both UPS and surge suppression devices require a grounding connection to function properly?

 

[Daniel Holzman]

I have read differing claims on whether a surge suppressor will work without a ground. One claim, by a seemingly knowledgable writer, was that high quality surge suppressor control lightning strikes by shunting voltage from one wire to another, and will work without a ground. Others have claimed that no surge suppressor will work correctly without a ground. So this seems to be a point of contention. Everyone seems to agree that a proper ground is a very good idea, however is it essential to allow a surge suppressor to work is, at least in my mind, an open question.

An uninterruptible power supply performs a different function, namely it is designed to keep your system operational during power failures. Many UPS systems also include surge suppression, and I have seen several posts saying that all UPS systems need to be grounded.

Bottom line, for a computer or other sensitive electronic equipment, I would spring for a good ground.