We are remodeling a 1920"s house that has had various electrical updates previous to our ownership. At the moment we are preparing the house for a electrical overhaul by a licensed electrician. Before doing this we want to educate ourselves. There are a mixture of 3 prong and 2 prong outlets. Testing the 3 prong outlets indicate many have an "open ground". What is an open ground and how do you fix it? Does it need to be fixed?

Open ground means just that. The ground conductor is either open (not connected) or it probably doesn't even exist.

I have an outlet at home that does just that (it was a three-hole socket and I have temporarily replaced it with a two-hole device until the wiring behind it gets replaced).

Judging by how old you say the house is (and the fact that there are two-hole sockets present), I'd say there's a good chance there is no ground.

[This message has been edited by SvenNYC (edited 12-04-2002).]

As Sven says this means that there is no ground connected to that receptacle.

I was recently at a house where I touched the metal faceplate of an outlet while plugging something in and happened to be leaning on the radiator. I got quite a shock. In this instance the remodel clips on the outlet box were touching the outlet screws on one side which made it an accident waiting to happen. There was a ground wire in the box but it was "open" (not connected) somewhere before it got to that outlet. If the ground was connected the breaker would've tripped and someone would know that there was a problem there.

BTW, this circuit also extended into the Kitchen (lighting circuit) which made the light switch next to the sink also "live", so it could've been real bad.

Bill

Depending on what the electrical updates were. 1920s homes were wired with knob and tube. No ground present, at the time they felt this to be safe, and it really wasn't a bad system because the neutral and hot conductors were separated. However, updating could be a problem if what you say is 3 prong outlets with no ground. Sounds like the person just replaced an old outlet without replacing the wiring. If it were my house, I would start by replacing the fuse box to circuit breaker with new service entrance cable, meter socket,and a new grounding system. 2nd I would run new lines to all the major appliances, like the refridge, counter outlets in kitchen, washer, dryer, heating system. After that I would replace wiring to easy acess places like the 1st fl receptacles, acssesed from cellar, after that I would try to replace lighting if not to much wall ripping is involved. Then proceed to the 2nd fl, using the attic for acess to walls and lights. Could be an expensive propostion, But if you replace the service and all major appliances with new wiring, you may be taking a big load of the system depending how it was wired. Then you can start replacing the rest of the wiring as your able to. Hope this helps a little.

[This message has been edited by Wirenuttt (edited 12-04-2002).]

2nd that Wirenuttt,
my fav anaolgy being the tree one, start with the trunk, progress to the branches.....

remarked , if you've some pix the crew here is never short on critique

Thanks for all your responses. Questions/comments on your responses...Wirenutt, the electrical is on a circuit breaker that we think dates to the 60's. Does this mean anything? What is knob and tube?

Sparky, what pictures would be helpful for a critique?

remarked;
A panel from the 60's might be good if it's the old bull dog type, pushmatic took over the line in the 70's. These panels are bolt in stlye circuit breakers which hold a high A.I.C. (amps interupting capacity) which means it has a high resistance to arc faults through transmission lines. If it's a F.P.E. (Federal pacific electric) it's junk, not sure if the trash man would even take it. This fpe type had a real bad problem with the style of the breaker fitting into the panel, they would loosen up, I've seen plenty of them where the cover actually held the breakers in place. This is a fire waiting to happen, because of resistance. Loose connections make resistance, resistance leads to heat, and if the load(appliance for instance)is drawing a lot of power this could lead to an electrical fire. KNob and tube is the first electrical installation introduced to the public. It's an open insulated conducter, not sheilded like the wiring methods of today, which is attached with ceramic that nails directlly to a joist. The tubes are ceramic sleeves that when penetrating through a wood member creates a sheild. The old timers will tell you it was the best method created because the hot and neutral were separated by several inches, as to not allow shorts. About the CIrcuit breaker panel: what size main do you have? IS it a 60 amp or a 100 amp main breaker. If it's a 60, it should be updated for that reason alone. Most homes over 1500 sq. ft. with gas appliances have 200 amp services. An electrician can do a demand load calculation for you to establish what you need to have by the code book.

[This message has been edited by Wirenuttt (edited 12-05-2002).]
Knob-and-tube wiring

This type of wiring was common in houses built before


[This message has been edited by Wirenuttt (edited 12-05-2002).]

Wirenutt...we will definitly check the circuit breaker panel for the information you have given us and how many amps the breaker is. Unfortunately we do not live in the house yet. It is about 2 hours away and we intend to go there Dec 13-15. So can we get back with you? In the meantime we have removed all the plaster, sheetrock from most of the walls on the first floor and gone around both floors putting notes on the walls and ceiling on what is needed...new plug, upgrade existing plug, move this plug, switch, overhead light, etc. The upstairs will have exposed walls but the downstairs won't. Now we think we are ready for the next step which is putting together a request for bids. Do you have any advice on this? Is there a preferred method for writing a bid? Is there anything else we can do to prepare for a electricians visit to the house? We appreciate your help.

Just my curiousity, but isn't the reason they replace the knob and tube wiring because of inductive heating?

Doing it right does mean using the tree analogy. But if you have to live with it while the work is done, it is possible to use a GFCI to work with a 3 prong plug as long as the receptacle is labeled "No Equipment Ground". It's safer than just leaving a 3 hole receptacle with an open ground. NEC 210-7(d)(3).

I think the invention of Romex and other cable methods is what caused K&T to go by the wayside.

IMHO the presence of an open ground due to absence of an equipment ground is grounds to replace the 1920's K&T wiring method with a 2002 wiring method.
Remarked,
When I say replaced, buddy, I mean all of it. Those old houses are cool, and I love 'em, but if you are going to "overhaul" it, go all the way with it. That ground wire is the path that the current is going to take back to the source in a fault condition. It will save your life if properly installed.

I can't play...I'm grounded,
Doc

remarked
I strongly agree with The Watt Doctor that you should replace or rewire the entire home to current code. The reasons he has stated are good enough, but I would like to add that your home would also be more marketable when (if) you decided to sell. It appears that more and more lenders are beginning to require rewire of K&T before they will approve a loan.

Bob

I appreciate all your responses. We are pretty sure the house no longer has knob and tube. The electric on the 1st floor is older than the 2nd floor which was done we estimate in the 60's when the basement was remodeled into a livable part of the house. There are some grounded plugs and a GFCI in the bathroom. Some switches and plugs don't work and there are many 2 prong outlets or 3 prong not gounded. We are not exposing the walls downstairs like we are with the 1st floor. Do you think it adequate to put GFCI on the ungrounded 3 prong plugs with label "not grounded"? Is there a way to tap into the outlets that are gounded without major damage to the walls?

Tapping into grounded outlets and other ways of trying to save money ends up costing you more money in the end. It's not that difficult for an experiencec electrician to install new wiring with new outlets.

Why do they still make 2 prong plugs on electrical devices then? Does the larger prong make up for the lack of the 3rd prong? There are plugs in the rented house we live in that have a little sticky label on them saying GFCI Protected Outlet. But they look like a regular plug. Are these those plugs that are not actually grounded but will interupt the current flow?

Remarked,
I would love to be able to further advise you about your house, but without being there, I can't. I'm sure the other members would chime in with a hardy amen as well. If there were a few of us there, I'm sure that we wouldn't all agree about what needs to be done.
At minimum all 2 wire outlets that are replaced with 3 prong outlets shall be the GFI type, or shall be suppied by a GFI. They shall be marked “No Equipment Ground”, or if supplied through a GFI shall be marked “No Equipment Ground” and "GFI Protected".
The other alternative is to replace them with 2 wire (2 prong) receptacles. 2 prong receptacles are still legal.
By the way, the larger prong is for "polarity". Some equipment is designed in such a way that the "way" in which it plugs into the outlet is important.
At this point in the game, I think you need an electrician.
I do want to encourage you to get a digital camera, take pictures, and post them so we can look at the progress, and possibly give you advice on specific items.
Another thing I would encourage is to not be afraid to take out sheetrock if it is called for. The only problem with your house is that it is probably done with "ship lap" in the walls, but anway, don't be afraid to tear something out. In the long run, you will be better off for having done it.

Good Luck,
Doc

I think I speak for everyone that the watt doctor has the right idea here. Get that camera.

I appreciate all your responses. I am learning a lot. We do have a digital camera and will be going to the house this coming weekend and will take pictures.

If you really want to learn, I'd like to suggest a book that I found to be extremely informative. It's called "House Wireint with the National Electric Code: by Ray C. Mullin, Delmar Publishers. It will really help you understand a not only the right ways to do things, but also the reasoning behind the NEC.

At ther very least, it will help you make better decisions and also to make sure that you can keep the electrician(s) you work with in check. It may also be helpful for any small projects that you may someday decide to tackle. Given your situation, I think it will certainly pay for itself in both the cost of the book, and also the time spent reading it.

There were two versions last time I looked, one bigger than the other and about twice the cost. I got the smaller ($25) version and refer to it any time I need a reference. The larger one looked to me to be a more thorough version of the smaller, but didn't cover many more topics.

This book is far better, IMHO, than the Black & Decker, Time Life, etc. books that you're likely to see at your local home improvement store. But unlike those books, it doesn't have all the photos of how to do smaller tasks like changing light fixtures.