All right, I'm feeling mildly dumb and a little sheepish not to mention
slightly sick here... just bought a house for the first time less than
a month ago, and knew that it had some minor wiring "issues" but now
that I'm assessing what I have it appears that there are bigger issues
than previously anticipated. Anyway, here's the deal. House is a two
story colonial with full basement, built late 1940's. Excellent
structural condition, lovely hardwood floors albeit in need of a
refinishing. Paid for a home inspection prior to placing a bid on
house. Inspector noted some electrical items that would be against code
now for new construction but nothing major (things like clothes washer
sharing a circuit with other receptacles, lack of GFCIs in the kitchen,
etc.) all receptacles in house are three prong type and tested OK with
cheap little $5 circuit tester. All visible wiring was old BX w/ cloth
covered conductors and inspector said that grounding through the armor
of the BX while not the way we do things now was perfectly OK. So I was
feeling pretty good about things electrically, and that gave me a good
feeling about the house, as I automatically anticipated issues with lack
of grounds etc. in a house of this age. Well some of the receps. were
a little loose and old looking so I bought a pack of new ones and
proceeded to replace them. Basement went fine. Got to the first floor
and identified some issues that will be easy to rectify. Then I got to
the three oldest circuits in the house, one of which started life as the
general first floor circuit and another the general second floor circuit
(the latter of which still serves the entire second floor.) The third
is a lighting only circuit which serves the lights at the stair
landings. It appears that throughout the house wherever the wiring was
hidden behind plaster it was run in NM not BX and there is no grounding,
period. I don't have a big problem with that on a lighting only circuit
but the receptacles installed on the first and second floor are
grounding type and it appears that the ground is provided by a jumper at
each receptacle between the ground terminal and the neutral. I realize
that *theoretically* this is functionally identical, but this isn't the
way we do things now, so it bothers me a little bit.
1) is this actually an acceptable method of retrofitting receptacles to
grounded type? I suspect not, but you never can tell.
2) if not, is this the kind of thing that would generally be covered by
a home warranty? We did spend the $$ for one, although AFAIK it
generally only covers things like appliances etc.
I don't blame the inspector for missing this one; he would have had to
pull a receptacle either on the south side of the first floor or
somewhere on the second floor to identify this issue; there's a lot of
wiring visible in the basement but it is all either BX or obviously
recently added Romex which does contain a ground, so there was no reason
to believe that this wasn't consistent throughout the house. However,
the transition from exposed BX to hidden NM seems to be original to the
house as far as I can tell; I wonder why that would be?
Any help, thoughts, advice, etc. greatly appreciated.
(it's a good thing the girlie was planning on repainting, I guess...)
replace "fly" with "com" to reply.
Definitely not kosher to connect the receptical ground terminal to the
Consider replacing those recepticles with GFCI types with "ground not
connected" labels applied to them.
If you can definitely confirm upstream and downstream recepticals you
could use GFCI recepticals in the upstream ones and continue using
recepticals without ground holes on the downstream ones, or use
grounding type recepticals with the same "ground not connected" stickers
As always, clear this stuff with your local electrical inspector he/she
may or may not go along with my ideas.
It is not correct to wire outlets in that fashion, and I wouldn't expect
your home warranty to cover it, because it's not "broken" or something that
broke down, just improperly wired outlets. For people protection you can
install GFCI outlets, but it doesn't help for equipment that needs to be
grounded, for that you'll need to run grounded cables to those locations
What equipment "needs" to be grounded?
You may find that today the answer is: not much!
Most audio/visual stuff (TVs, Stereos) doesn't have a ground.
I have a window A/C that has a GFCI built into the plug (which does have a
ground). But there isn't a ground wire to the case of the A/C.
Not at all.
They work just fine, thank you, with a "floating" ground. Often, however,
where these is a ground provided there is a network which provides a small
leakage path between BOTH power conductors and the chassis (ground). The
effect of this network would be to cause the chassis get a voltage on the
order of 55 volts. There is no shock hazard and the leakage of even
several of these systems is not likely to trip a GFCI.
There is a lot of "tradition" here.
When IBM started making PCs they had a ground. When folks starting making
audio/visual stuff include stereos and TVs, there usually wasn't a ground.
But both classes of equipment have user exposure to the "chassis." In the
audio/visual stuff its from the "RCA" female connectors. In the PC world
it's the connector shell including the mouse, keyboard, USB stuff, printer
and serial interface.
On Fri, 20 Oct 2006 08:04:56 -0400, John Gilmer wrote:
There's a big difference between A/V equipment and computers. Well, at
least in Europe, I don't know much about US regulations.
Most A/V stuff has reinforced or double insulation. That's why they
have a plug without ground. Computers (except some laptops) usually
have only 'normal' insulation. A single fault in the insulation can
create a connection between the live pole and the cabinet. Without a
grounded cabinet, that could be lethal. With grounded cabinet, you just
blow a fuse.
In case of fire or other damage, the insurance company can give you a
hard time, if they find out that you have class I equipment connected to
a socket without ground.
BTW: the 55 V you mentioned (115 V over here) is more than enough to
blow a serial or parallel port when connecting a grounded printer to a
non-grounded PC. For me, that's also a good reason to ground my PC.
I found it interesting to discover that some two prong "wall wart"
transformers have a high value resistor (in the order of 500K ohms)
connected between the wide plug blade and the secondary of the
transformer to drain off static charges from the chassis of whatever it
is they are powering.
That large a resistance could only deliver about 250 microamps of "shock
current" if the receptical it was plugged into was crosswired hot to
Not really. In both cases there is a transformer isolating the power from
the load. I grant that the "switching" power supply used in PCs has a good
amount of circuitry (the "switches") before the transformer -- "they convert
the incoming AC to DC and then convert it to a higher frequency. At higher
frequencies the transformer can be made a LOT smaller. In switching input
also lets the power supply accomodate a very large change in input voltages
without problem. There is no good reason why "they" could not make a PC
power supply that made the PC as safe as your TV without relying upon a
Again, I point out that LG (the Korean company, formerly known as Lucky
Goldstar) now ships it's Chinese made room air conditions with a GFCI built
into the plug but with NO ground wire going to the chassis.
I also like to point out that you are somewhat safer if metal objects in
your environment "float" rather than be grounded. If your left hand is
resting on a well grounded object and your right hand touches something
electrically HOT, you may get a fatal shock. If your left hand is resting
on a "floating" metal object you might get a little "tingle" when your right
hand hits the HOT wire.
Tradition counts for a lot is setting standards. BUT, had cheap and
reliable GFCI technology been available when electric power was "new" it's
quite likely that "grounding" may not have been as important.
True. Nonetheless, it's possible to make a PC power supply that is as safe
as that in your television or DVD player. The next time I have both a dead
PC power supply and a dead VCR I will open both up and see whether the PC
supply is any more likely to generate a HOT to Ground cross that the VCR.
Unless it was the cause of the fire, the insurance company will not say a
thing. Moreover, codes permit sockets with ground openings that are not
grounded so long as: 1) the circuit is protected by a GFCI; and 2) there
is a "not grounded" label applied. Read the installation instructions on
your GFCI (I may be making an incorrect assumption about GFCIs "over
there."). In the States, the insurance companies have better have a VERY
good reason to give your a "hard time." A company that drags its feet over
a payment risks paying fines to the regulators and risks being successfully
sued by the insured with truly massive "punitive" damages.
No. It would be current limited. Likewise, if you rub your feet on the
carpet in winter and build up a 20,000 volt charge (which happens) you
likely would not fry something it you touch a signal pin. It's all a
matter of how much energy you can dump into the interface.
Your grounded printer would "ground" your PC. No harm, no foul.
No, it's definitely some early type of NM, although it may not be
officially designated as such. There's two plastic-insulated conductors
(that must be a pretty early use of same; as far as automotive stuff
goes I believe the transition was made about 1955 - at least it was for
Studebaker; I have a '55 coupe which (fortunately) has plastic
insulation on the wiring) in what appears to be a tar-impregnated cloth
jacket. But no ground.
I really, REALLY don't want to have to rewire two complete circuits,
although at this point it kind of looks like I'm going to have to. I
might even have to involve a *gasp* electrician due to the magnitude of
what this project looks like it's shaping up to be, which makes my
Y-chromosome cower in shame. I suppose I could just install new
non-grounded receptacles ahd that would be technically correct, although
then I'm back where I started, as there's computer equipment on the
second floor, and a UPS theoretically should have a ground... also
would feel better if the stuff in the bathroom were grounded (although I
was thinking of rewiring the bathroom anyway to meet current code with a
dedicated circuit, GFCI, etc. which is somewhat doable as there's a
small chase going down to the basement behind the bathtub, and an access
panel, so it's "just" a matter of getting a cable from behind the
bathtub up into the attic and then back down to the light switch...)
I suppose it's not acceptable to cheat and ground stuff to the nearest
replace "fly" with "com" to reply.
You can still buy ungrounded receptacles and put things back like
original. Most circuits don't really need a ground, like the upstairs
bedroom convenience outlets.
Where you really need grounds (bathroom, kitchen counters near the sink,
your computer UPS, etc,) you can run a separate green wire back to the
service panel ground (or to the nearest grounding electrode conductor,
if that is easier.) The ground wire does not have to run with the
current-carrying wires if you are updating old work.
You can also install a GFCI breaker and then use 3-wire receptacles,
leaving the ground terminal disconnected. In this case, you technically
need to put a sticker that says "GFCI Protected. No Equipment Ground."
on each of the grounding outlets that has a floating ground.
You can also protect circuits by wiring them thru the LOAD terminals of
a GFCI receptacle.
The most practical solution will probably end up being a mixture of
these methods. HTH :-)
i would run a seperate ground wire to the effected outlets.
how many are a problem? 5 10 50?
most older homes have few outlets, might be time to upgrade.
do not connect grounds to neutrals in the right situation it can
that may be doable at least upstairs; is it kosher to run, say, THHN
without conduit or greenfield or would I need some kind of plenum rated
wire? Please excuse the dumb questions; I know a lot about fire alarm
but just enough to be dangerous about plain old electrical stuff. Since
I really like this house (and paid enough for it!) I'd like to "do it
right" whenever possible, and certainly would like to be able to say
with a straight face to any prospective buyers in the future that
everything is up to snuff.
replace "fly" with "com" to reply.
From what I can tell, the electric code is silent about that. I just
run a #12 green THHN / THWN-2 wire inside the wall cavities, staple to
the ceiling joists, etc. I run them as neatly as possible and where
they are unlikely to be physically abused. I ground them at a big
split-bolt connector on the main grounding electrode conductor a couple
of feet from where it goes into the electric panel.
I have an older house, and I'm trying to get one properly grounded
duplex outlet in each room, and I don't worry about the ungrounded
convenience outlets. All the basement, bathroom, and utility room
outlets are grounded and GFCI'ed (except the outlet for the freezers.)
All the kitchen outlets are grounded except for one that I couldn't get
a ground wire to so I installed a GFCI receptacle. (the one that I
couldn't ground just happened to be the outlet close to the sink)
Thanks to you and to the others who replied. I have a coworker who is a
master electrician as well and he also suggested the separate ground
wire, so I think that that may be the plan of attack for the first
floor. Here's what I'm thinking:
-buy some new circuit breakers. I have four spare spaces in the breaker
panel, but I'm going to see if I can get some half-height breakers just
in case I want to add a 240V circuit in the future.
-split the washer and dryer onto their own circuits. (they are
currently sharing circuits; the washer with the hall lighting and the
dryer with the dishwasher.) Also run a dedicated circuit to the (gas)
stove (currently shared with the hall lighting and clothes washer.)
Should this be 20A or is 15A sufficient? I was thinking 15A would be OK
but if current code recommends 20A that's what I'll do.
-If feasible, provide a new 20A circuit for a single receptacle on the
kitchen counter that's currently shared with the 1st floor lighting ckt.
(the other is already on a 20A circuit, and I've installed a GFCI
-Again, if feasible, provide a new 15A circuit dedicated for the
bathroom. cut box out of wall and replace single gang box with light
switch with double gang box for light switch and GFCI receptacle. Leave
pull string up to attic for future installation of an exhaust fan.
-On the first floor, run a single green 14AWG THHN from breaker panel to
receptacles coming up from below and then dropping back down again,
working my way around the perimeter of the house. One homerun for each
circuit (there are two.) Light switches and light fixtures remain
ungrounded; there seems to be no way to deal with those short of
breaking up some very thick and sturdy-looking plaster.
-On the second floor, either follow the same plan as above, but dropping
down from within the attic, or else find the homerun and ground that
back to the breaker panel using the chase behind the bathtub and then
completely rewire the rest with 14/2 Romex from the attic (should be
possible, although I suspect this house was wired "old style" with
switch legs dropping down from the ceiling light fixtures so I may leave
the light switches ungrounded.)
I'm starting to think that maybe I can do this (assuming, of course,
that She Who Must Be Obeyed displays an aptitude as a fish tape
operator,) although I'm wondering if I'm approaching the point at which
I need to pull a permit. I certainly don't want to piss off the various
local agencies as I do need to deal with them at work.
replace "fly" with "com" to reply.
You are on the right track to just add the ground wire where possible,
it is much easier. My wife has, over the years, become extremely adept
at grabbing fishtapes in wall cavities with bent coathangers. WIthout
her help, I would still be doing some projects that have been completed
years ago. I prefer metal boxes with ears that pull out when the
screws at the side of the box are tightened. The plastic boxes with
the tabs that rotate out don't have as much area pushing against the
back of the sheetrock/plaster as the flat tabs on the metal boxes.
Also, the plastic boxes do distort their shape a little while the metal
boxes are more rigid.
H. R. (Bob) Hofmann
Where do you find metal old work boxes? My local "big box" hardware
stores do not have them, although I've seen some of the contractors I
work with using them, I believe they get them from supply houses where
they have accounts.
Don't have a Lowe's, but Home Despot doesn't have them, at least not
out and on the shelf. Unfortunately the quality of help at Home Despot
is... not so good, so they look at me blankly when I ask questions.
Steve Barker LT wrote:
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