Ungrounded wiring

[allinon72]

My house was built in 1948 and most of the wiring is 2 wire with no ground. Nothing wrong with the electrical system but that fact just bothers me. What options do I have short of rewiring the whole house? Is there something I can add to the panel that will provide some sort of ground protection?

 

[6768rogues]

I would gradually rewire the house over time. There are ways to get wires into difficult locations. My house is a little older but was wired in the 30s or 40s. Not only was it ungrounded, but the insulation was brittle and literally falling off wires in places. New wire insulation is much improved. I have seen old houses where mice or other vermin chewed insulation off wires. Back in the 40s, there was not much plug load in many rooms other than a light. Now we are heavily dependent on electricity. Buy some smoke detectors and rewire the house as you are able.

 

[KenC]

If the wire and insulation is in good physical condition, you can install GFCI recepts. That will provide protection at least as good as a ground conductor, at least for the recepts. Lighting is typically easier to access so I'd just pull new wire for that.

 

[FreddiFiche]

If the wire and insulation is in good physical condition, you can install GFCI recepts. That will provide protection at least as good as a ground conductor, at least for the recepts. Lighting is typically easier to access so I'd just pull new wire for that.

Right on. Do it with breakers, or find the first outlet in each circuit, and install a GFCI receptacle, and daisy chain the rest of the circuit off the 'load' side. (You don't need a GFCI receptacle at each place you have a outlet.

In lay terms, a GFCI checks to see if you have the same current coming back, as is going out. If there is a difference, it 'knows' that some of the current is being leaked, and possibly through you. it will then trip. A GFCI protected outlet is as safe as a grounded outlet.

Then you can go slowly, as needed, and replace conductors with a metallic ground at you leisure.....

 

[6768rogues]

Right on. Do it with breakers, or find the first outlet in each circuit, and install a GFCI receptacle, and daisy chain the rest of the circuit off the 'load' side. (You don't need a GFCI receptacle at each place you have a outlet.

In lay terms, a GFCI checks to see if you have the same current coming back, as is going out. If there is a difference, it 'knows' that some of the current is being leaked, and possibly through you. it will then trip. A GFCI protected outlet is as safe as a grounded outlet.

Then you can go slowly, as needed, and replace conductors with a metallic ground at you leisure.....

If your wiring is in good shape, this is an option. I tried with mine and simply bending the wire to put it into a new panelbox caused the insulation to crack and crumble.

 

[FreddiFiche]

If your wiring is in good shape, this is an option. I tried with mine and simply bending the wire to put it into a new panelbox caused the insulation to crack and crumble.

yuck....seen that that before....the 'white conductor' is usually dark brown....and I concur....IF the existing is crappy....don't risk moving it around.

 

[VHF]

If you have any concerns about the integrity of the existing wiring/insulation, using AFCI (arc-fault) breakers would provide an additional measure of protection. I think they are silly in new houses as now required by NEC, but make a lot of sense in an older house with questionable wiring.

If the wiring is physically in good shape and the only concern is lack of a grounding conductor, then using GFCI breakers or outlets will provide some good protection.

If using a standard 3-prong GFCI receptical in place a 2-prong receptical in a box where a ground wire is not available, it is required by code to label the recepticle "No Equipment Ground".

Note that GFCI will provide good shock protection, but won't allow plug-in surge suppressors to divert surges into ground. Either add a whole-house surge supressor at your main panel or run a new 3-conductor cable with ground to the outlets for your critical/expensive electronics.

It used to be common to run a separate ground wire (tied to a water pipe or back to the panel) to an existing 2-prong outlet in order to upgrade it to 3-prong, but this method is no longer code-compliant.

For lamps and other 2-prong applicances there is really no problem with having a 2-prong receptical--and no real advantage in upgrading the 3-prong. For computers or other electronics having a true ground is useful for discharging static or surges. For 3-prong household applicances or power tools, using a GFCI will provide a measure of shock protection if a true ground isn't feasable.

 

[allinon72]

Note that GFCI will provide good shock protection, but won't allow plug-in surge suppressors to divert surges into ground. Either add a whole-house surge supressor at your main panel or run a new 3-conductor cable with ground to the outlets for your critical/expensive electronics.

THIS is what I want to know more about.

I have access to the entire house from above and below, so I've been considering rewiring one room at a time.

 

[sparky67]

My house was built in 1948 and most of the wiring is 2 wire with no ground. Nothing wrong with the electrical system but that fact just bothers me. What options do I have short of rewiring the whole house? Is there something I can add to the panel that will provide some sort of ground protection?

Is the wire in a metal jacket? The only two wire I've seen is BX cable. The metal jacket was the ground so no extra wire was run. The ground connection was made by clamping the jacket too the box. If this is the case all you need to do is add a ground screw in the box and run a pig tail to your receptacle. The only caution I would add is that a loose clamp in one box would break the ground for all the other outlets so its still a good idea to use GFCI or AFCI breakers. Also use one of these cheap circuit and GFCI checkers to verify your wiring. circuit tester

At least this will allow you to plug in surge protectors. Its always best to have a whole house surge protector and a local one at the point of load. A whole house surge protector is attached right to the panel and gets wired to one breaker on each phase. Whole house surge protectors can handle much more energy then the surge strips you plug into the wall, but some times that means they clamp at higher voltages or have slower clamping times allowing some of the surge to 'get by'. If the surge is bad the surge protector may trip the breaker protecting any equipment on that circuit but leaving everything else unprotected for future surges. If it doesn't trip the breaker it probably was somewhat damaged and wont handle the next surge as well or at all, but your surge strip which saw almost none of the first surge will have a chance to handle the second. So think about which breaker to wire it too and dont throw away the surge strips.

 

[kert]

Is the wire in a metal jacket? The only two wire I've seen is BX cable. The metal jacket was the ground so no extra wire was run. The ground connection was made by clamping the jacket too the box. If this is the case all you need to do is add a ground screw in the box and run a pig tail to your receptacle. The only caution I would add is that a loose clamp in one box would break the ground for all the other outlets so its still a good idea to use GFCI or AFCI breakers. Also use one of these cheap circuit and GFCI checkers to verify your wiring. circuit tester

At least this will allow you to plug in surge protectors. Its always best to have a whole house surge protector and a local one at the point of load. A whole house surge protector is attached right to the panel and gets wired to one breaker on each phase. Whole house surge protectors can handle much more energy then the surge strips you plug into the wall, but some times that means they clamp at higher voltages or have slower clamping times allowing some of the surge to 'get by'. If the surge is bad the surge protector may trip the breaker protecting any equipment on that circuit but leaving everything else unprotected for future surges. If it doesn't trip the breaker it probably was somewhat damaged and wont handle the next surge as well or at all, but your surge strip which saw almost none of the first surge will have a chance to handle the second. So think about which breaker to wire it too and dont throw away the surge strips.

The older BX cable jacket is not a suitable ground. First, it is steel which is not as good a conductor as Copper or Aluminum, but also, the coils don't necessarily make electrical contact, so you may effectively have a coil (think heating element) rather than a good path to ground if you ever had a short to the jacket.

 

[sparky67]

The older BX cable jacket is not a suitable ground. First, it is steel which is not as good a conductor as Copper or Aluminum, but also, the coils don't necessarily make electrical contact, so you may effectively have a coil (think heating element) rather than a good path to ground if you ever had a short to the jacket.

Agree, but its better then only having a GFCI.

 

[MoonRise]

Is the wire in a metal jacket? The only two wire I've seen is BX cable.

Could also be 'old' plain 2-wire cable (IIRC, some of the 'old' rubber/tar cloth-covered cable that disintegrates if you look too hard at it or sneeze in its direction was just 2-wire), or it could maybe be two wire inside metal conduit (with the metal conduit serving as the 'ground'), or it could be really old knob-and-tube type (completely separate lines, sometimes snaking off in completely different directions and just coming back in the general vicinity of one another at the outlet/switch).

http://en.wikipedia.org/wiki/Knob_and_tube

If the existing 2-wire (insulation condition mostly) is in OK condition, leave as-is and maybe add the GFCI outlet(s) as desired for a little addition safety. IMHO.

If the existing wiring is showing insulation degradation, then replace and 'upgrade' the wiring itself and possibly also the infrastructure and layout of the wiring 'system' (our society now is a lot more dependent and used to electrical devices, as opposed to 'way back when' where an entire house might have had a 'whopping' 30 or 60 amp service and just a single-digit number of different circuits for the whole house). Possible new service entrance and meter (for the addition ampacity), possible new panel (for the ampacity and the total number of circuits all over the place), new wire and new circuits and new outlets and switches and whatnot. More $$$ obviously, and you almost always then have to bring the electrical system up to completely 'current' (no pun intended) electrical standards and Codes (breakers, circuits, wires and cables, outlet and switch amounts and spacing and locations, and whatnot).

 

[wellpoison]

gfci receptacles would do the trick for the most part. but remember gfci's are meant to be people protectors not equipment protectors (meaning they protect from electrical shock). your equipment ground conductor allows the circuit breaker to trip. a which shuts off that whole circuit. gfci's shut power off to that recep and everyone after it but does nothing if the wire coming into is shorted out, which could result in overheating.

 

[allinon72]

I'm all about safety but I ask this question more as a way to save the stuff I have plugged in. The wiring has the cloth insulation, I do not think it is original to the house as I'm not sure it was used in 1948. It is not knob and tube.

Looks like I'll have to read more into the whole-house surge protector.

 

[allinon72]

My wiring looks exactly like the gray wiring spliced in the knob and tube in this pic:

 

[info2x]

I've seen two styles of the wiring you show in that picture. One identical, nice insulation on each conductor. The other style looked the same from the outside, but each conductor appeared to be insulted with rubber and cloth which overtime got brittle and when I touched it cracked.

edit: I would probably rewire slowly, but I'm ****.

 

[allinon72]

Honestly it wouldn't be as hard as some houses as I have easy access above AND below. Seems like that would mean minimal hacking of the drywall but things are never that easy.

 

[sparky67]

Of course knob and tube would be ungrounded but I was quite sure that was long gone before they built your house.

I've seen two styles of the wiring you show in that picture. One identical, nice insulation on each conductor. The other style looked the same from the outside, but each conductor appeared to be insulted with rubber and cloth which overtime got brittle and when I touched it cracked.

edit: I would probably rewire slowly, but I'm ****.

There may be other types of this gray wire I haven't seen but the stuff I have seen always had a ground wire. Usually its a much smaller gauge wire then the others. If you dont see the wire in the box, take a closer look. I've seen where they wrap it back over the insulation to the outside of the box only using the clamp to make the ground. I've also seen where they put it under a screw from the outside of the box. I guess when this stuff first came out guys that were use to working with BX didn't really know what to do with the ground wire.
By the way Ive been told that the cloth type is made with asbestos. Not sure if that's true but what wasn't built with that stuff back then anyway.

One other thing if you start adding grounding. You should check that the panel is actually grounded.

 

[VHF]

THIS is what I want to know more about.

As long as you have a good ground at your main panel (from a ground rod and/or buried metal water pipe), you can put a whole house surge protector at your main panel.

Manufacturers instructions vary as to whether a 240V double pole breaker is required or two separate 120V brakers can be used and whether the surge suppressor can share a breaker with an existing circuit.

Here are a couple popular models:

Intermatic IG1240RC3
SyCom SYC-120/240-T2

As already mentioned, these aren't really intended as a substitute for individual surge protectors for computers/TVs, but are intended as an additional line of defense (and to provide some protecton for other appliances such furnace and fridge.)

With no ground at your outlets it may be your only option right now to provide some level of surge protection.

 

[info2x]

Of course knob and tube would be ungrounded but I was quite sure that was long gone before they built your house.



There may be other types of this gray wire I haven't seen but the stuff I have seen always had a ground wire. Usually its a much smaller gauge wire then the others. If you dont see the wire in the box, take a closer look. I've seen where they wrap it back over the insulation to the outside of the box only using the clamp to make the ground. I've also seen where they put it under a screw from the outside of the box. I guess when this stuff first came out guys that were use to working with BX didn't really know what to do with the ground wire.
By the way Ive been told that the cloth type is made with asbestos. Not sure if that's true but what wasn't built with that stuff back then anyway.

One other thing if you start adding grounding. You should check that the panel is actually grounded.

I've exactly what you are talking about, but I've also seen it without the ground. What he has pictured I would expect a ground, but just cut off like you said, but my experiance is one house that was wired in an unsafe manner. I could pull 80 amps or so through one outlet because he had several breakers all tied together