We just bought a new house and want to upgrade the electrical system,
some of which was done in the 60's when the house was built. The vast
majority of the electrical outlets have only 2 wires, the ground
terminal is missing.
Some of the outlets are in the basement, where the wiring is partially
Is it legal (according to the electrical code) for me to change the
outlet to a more modern 3 prong type and to obtain a ground from a
nearby copper pipe or from one of the nearby plugs that already have a
3 prong outlet???? I notice the previous owner did this in several
locations, but I need to know if it's legal to obtain a ground in this
We live in Maine, but belive the National Code is the one that has
You should not use the plumbing system as the path-to-ground
for your outlets, no. The simple "solution" is to replace
the receptacles with GFCI outlets, and mark them "no equipment
ground", (which labels ought to come with the recepticles).
This will get you within shouting distance of the same level
The complex solution is to run completely new wire.
An intermediate solution is to pull a separate ground
wire, and run it back to your service panel.
If you do that, you want to make sure that no ground
wire serves the devices on more than on circut, and
that each one is big enough to handle the circut it's
Probably. Esp. if you use 10 AWG wire. I mean, how likely
are you the get three simultaneous high-resistance shorts
from the same leg of your panel?
But I know that the the former works, is safe,
and is legal, and I don't know any of that for sure about
Equipment Grounding Conductors (EGCs) are sized for the size of the
largest Over Current Protective Device supplying the conductors in a
given box or other enclosure. As an extreme example lets use a junction
box for the kitchen and laundry circuits in an apartment. If the box
contains a fifty ampere stove circuit, a thirty ampere dryer circuit, a
twenty ampere laundry circuit, a twenty ampere multiwire kitchen counter
top circuits, a fifteen ampere multi wire dishwasher and disposal
circuit, and a fifteen ampere multiwire refrigerator and microwave oven
circuit it still only needs one equipment grounding conductor. That EGC
is sized for the fifty ampere breaker for the stove. The only reason
that the US NEC would require you to increase the size of the EGC is if
you increased the size of the current carrying conductors to compensate
for voltage drop. It just is not likely that there will be simultaneous
faults on two or more of the circuits that EGC was installed to protect.
Well we aren\'t no thin blue heroes and yet we aren\'t no blackguards to.
If you are planning to pull a ground wire back to the panel, you might
as well just plan on rewiring the outlets properly and legally with
new grounded cable. Any separate ground that you run is going to be
a kluge install and most likely would not pass code with an honest and
knowlegable electrical inspector. Not being code compliant can
affect your liability and fire insurance coverage.
As another poster says, if you don't want to go to all that trouble
and expense, putting in the GFCI's with the appropriate labels would
be the easy (and perfectly legal) way to go.
I haven't checked the most recent revision of the code to make sure it's
still there, but the code specifically allows you to run a separate
ground wire when upgrading old work. Think about it; the old ungrounded
wiring is code compliant because there was no grounded requirement when
it was installed. Adding a supplemental grounding wire can only make it
safer (assuming the grounding wire goes back to the panel or grounding
electrode system so a fault can't energize another circuit.)
Anything you touch is going to have to meet current code and the old wiring
probably won't if it's sixty years old. If you're going to pull a
ground through your walls, pulling new wiring isn't much more trouble.
Thank you all for commenting, I appreciate all the info!
I went down in the basement and pulled the cover off the entrance
panel. The inspection I did was very interesting, especially in light
of all the comments I've received to this post.
The large (existing) ground wire that goes to the ground rod near the
water main entrance IS the system ground for the electrical panel!!!!!
Although the panel is on one end of the house and the water main is on
the opposite end, it appears the original installer ran 50 feet of
large gauge copper across the middle of the basement in order to
ground the electrical service entrance panel.
So, that big ole copper wire that is very accessible should make a
Regarding the comments by some that I should just rip out the old 2
conductor wire and install 3 conductor wire in it's place..... do keep
in mind that the basement is finished, and gaining access to all the
wires that feed the house would require a major demolition and
restoration after the new wires were run. Not very practical::>
However, adding a ground wire is much more practical because the added
ground wire doesn't have to follow the path of the original 2
Again, thanks to all who commented, I'll post an update here later on.
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