Hello all. Just a question about 220V wiring for you. I've encountered
several 3-conductor 220V circuits recently. Doing a little research, I
see that around 1965 or so it was changed to requiring 4-conductor to
seperate the ground and neutral (vs. the old two hots and the third wire
being both the ground and the neutral).

Am I correct in the above? (may only be residential NEC stuff).

Does anyone know if having the neutral and ground share a conductor is a
bad thing? Does having a seperate ground really help with safety? Is
some equipment effected by the N/G binding, or a seperate N and G?

Thanks in advance!!

Chris

Hello all. Just a question about 220V wiring for you. I've encountered
several 3-conductor 220V circuits recently. Doing a little research, I
see that around 1965 or so it was changed to requiring 4-conductor to
seperate the ground and neutral (vs. the old two hots and the third wire
being both the ground and the neutral).

Am I correct in the above? (may only be residential NEC stuff).

The three-wire cable did not "combine" the neutral and ground,
the three wire cable HAD no neutral. 220V has no neutral, it
uses two 110V wires of opposite polarity. The fourth (N) wire
is for modern equipment that also has 110V circutry in it.

Yes, it is both dangerous and forbidden to combine or interconnect
the two.

Is it just me, or do we get this question every day?

--Goedjn

According to :
Is it just me, or do we get this question every day?

Just about. Worse, it's the same guy telling them that neutral
and ground are the same thing every time.

I need to get the FAQ updated and into autorepost.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

"Chris Lewis" wrote in message
...
According to :
Is it just me, or do we get this question every day?

Just about. Worse, it's the same guy telling them that neutral
and ground are the same thing every time.

Maybe I am that guy!
The 240v circuits to my A/C, oven and dryer have two hots and an
"uninsulated neutral" (some manufacturers call it a "bare neutral". Say
what you what, that is the official designation. And of course, it is
attached to the chassis, so it is also the ground. Every house on my
street, and millions of others, are wired identically. What is the last
time you heard of a problem with it?

The ground and the neutral aren't the same thing, but they are the same
wire.

"Toller" wrote in message
...

"Chris Lewis" wrote in message
...
According to :
Is it just me, or do we get this question every day?

Just about. Worse, it's the same guy telling them that neutral
and ground are the same thing every time.

Maybe I am that guy!
The 240v circuits to my A/C, oven and dryer have two hots and an
"uninsulated neutral" (some manufacturers call it a "bare neutral". Say

I just bought a new maytag dryer they tried to hand me a 3 wire plug. I
nixed it they said it was just fine. I said if they want to complete the
order get the right part. They did and all is well. My new home circa 1999
has four wire even for the water heater. Which was good when I connected the
time clock.

what you what, that is the official designation. And of course, it is
attached to the chassis, so it is also the ground. Every house on my
street, and millions of others, are wired identically. What is the last
time you heard of a problem with it?

If there was not a problem with it why was it changed. Every time you use a
ground as a neutral you ask for problems. Granted it does not happen very
often. But it does happen.
The industry has learn a few things in the last 30 years and all that the
NEC does is set a mininum standard. When followed the installation will be
safe for all concerned.

The ground and the neutral aren't the same thing, but they are the same
wire.

Excuse me, No they are not.
A ground is a non current carrying conductor most of the time. A neutral
carries current and voltage. That is why it is insulated all of the time a
ground can be both insulated or bare.

If there was not a problem with it why was it changed. Every time you use
a
ground as a neutral you ask for problems. Granted it does not happen very
often. But it does happen.

So you say, but cite an incident.
I know the problem is that if the neutral connection at the breaker box
opens, the chassis is potentially hot. Aside from being unlikely (what is
the last time you had a neutral connection at the breaker box open?) it is
dumb. If the chassis is hot, it is because there is an open circuit. If
there is an open circuit, the appliance will not be working. So, you have
to have an open neutral, not notice the appliance is not working, and be
well grounded (since you will be in series with the appliance.)
Sure, with 50,000,000 such circuits out there, there is probably a problem
now and then, but you probably have a bigger risk of being hit by lightning.

The industry has learn a few things in the last 30 years and all that the
NEC does is set a mininum standard. When followed the installation will be
safe for all concerned.

The ground and the neutral aren't the same thing, but they are the same
wire.

Excuse me, No they are not.
A ground is a non current carrying conductor most of the time. A neutral
carries current and voltage. That is why it is insulated all of the time a
ground can be both insulated or bare.

Sure they are the same wire on my 240 circuits; weren't you paying
attention? Contrary to what you just said, my neutral is not insulated.

According to Toller :

"Chris Lewis" wrote in message
...
According to :
Is it just me, or do we get this question every day?

Just about. Worse, it's the same guy telling them that neutral
and ground are the same thing every time.

Maybe I am that guy!
The 240v circuits to my A/C, oven and dryer have two hots and an
"uninsulated neutral" (some manufacturers call it a "bare neutral". Say
what you what, that is the official designation. And of course, it is
attached to the chassis, so it is also the ground. Every house on my
street, and millions of others, are wired identically. What is the last
time you heard of a problem with it?

Evidently the NEC heard of enough to change the practise.

The ground and the neutral aren't the same thing, but they are the same
wire.

Not anymore. NEC now forbids that practise in new construction.

CEC hasn't permitted it for at least 3 decades.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:
According to Toller :

"Chris Lewis" wrote in message
...
According to :
Is it just me, or do we get this question every day?

Just about. Worse, it's the same guy telling them that neutral
and ground are the same thing every time.

Maybe I am that guy!
The 240v circuits to my A/C, oven and dryer have two hots and an
"uninsulated neutral" (some manufacturers call it a "bare neutral". Say
what you what, that is the official designation. And of course, it is
attached to the chassis, so it is also the ground. Every house on my
street, and millions of others, are wired identically. What is the last
time you heard of a problem with it?

Evidently the NEC heard of enough to change the practise.

The ground and the neutral aren't the same thing, but they are the same
wire.

Not anymore. NEC now forbids that practise in new construction.

CEC hasn't permitted it for at least 3 decades.

Lots of good information in here (and some good/bad opinions).

Related then is the following; my house was built in 1965 and uses a bonded
G/N for my 110/220 outlets (stove to be precise). Everyone seems to agree
that a seperage G and N are a _good idea_, and I agree with that. Is it worth
it to run a new 4-conductor line to my stove for such a refit?

Something that may make this a moot point; mt main electrical box has bonded
neutral and ground bus-bars. So, any improvements I make up the line won't
really help as the box is old design. Probably have to replace the box as
well.

An I on target here?

Thanks in advance,
Chris

....
Yes, it is both dangerous and forbidden to combine or
interconnect
the two.

Is it just me, or do we get this question every day?

--Goedjn

No, it's not you, but I suspect that was rhetorical, right?
Too many people have been taught to look at these things
from a voltage standpoint, (e.g. 0Vac = 0Vac = how you get
it doesn't matter), instead of correctly considering current
flow and direction plus fault control.
I'll never forget my first encounter with ground
currents: HOW could a wire overheat and melt, when there
was 0V measured at BOTH ends of it? I watched 3 wires burst
their insulation into flames before I figured it was a
problem with me preventing knowing what went wrong! I was
an avionics TS at North Island at the time. Of course, if
I'd known to use the right meter scale, I'd have seen the
voltage diff, but ... .

Regards,

Pop

It is comforting and speaks well of this group that such
knowledge and participation exists here.

According to Chris Eller :

Hello all. Just a question about 220V wiring for you. I've encountered
several 3-conductor 220V circuits recently. Doing a little research, I
see that around 1965 or so it was changed to requiring 4-conductor to
seperate the ground and neutral (vs. the old two hots and the third wire
being both the ground and the neutral).

4-conductor circuits aren't "240V circuits" per-se. They're 240V/120V
circuits. The only place where a homeowner would normally be concerned about
four-wire circuits are stoves and dryers which need both 240V and 120V. US
code now requires that new stove/dryer installations must be four wire, wheras
it used to permit 3 wire. Canadian code hasn't permitted 3 wire stoves/dryers
for several decades.

Pure 240V circuits (ie: 240W water heaters) are _still_ 3 wire. They don't
need neutrals at all.

Does anyone know if having the neutral and ground share a conductor is a
bad thing? Does having a seperate ground really help with safety? Is
some equipment effected by the N/G binding, or a seperate N and G?

Sharing the neutral and ground _can_ be quite dangerous thing, that's why
they changed the code and no longer permit it in the last remaining
exception I'm aware of in the NEC.

Ie: if you have a neutral separation in the main panel, the frame of your
stove _may_ go hot.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.