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Neutral Switching

J

Jimmie

Jan 1, 1970
0
Lately I have come across two cases of switching the neutral in commercial
equipment. I had always heard this was a bad thing to do. The only reason I
can figure on doing this is to be able to detect a ground fault without
energising the motors. I this correct?
 
S

SQLit

Jan 1, 1970
0
Jimmie said:
Lately I have come across two cases of switching the neutral in commercial
equipment. I had always heard this was a bad thing to do. The only reason I
can figure on doing this is to be able to detect a ground fault without
energising the motors. I this correct?

Most situations off mean off. Using this method off means that it is still
energized and looking for somewhere to go.

We used to call it a California 3 way.

Change it out.
 
R

Roy Q.T.

Jan 1, 1970
0
I don't think it's correct, many contractors bid the jobs then send
inexperienced mechs to install the works involved & they wire them as
well, so, there is a good possibility it was wired incorrectly.

I've seen many haywire commercial installations that look like crap, i
always mention it to whom ever hired me but I stay away from them if
it's not my installation, lots of them have short circuits and are
poorly grounded if they are grounded at all. If you specialize in that
type of commercial installations, Check out the Codes Thoroughly & Good
Luck.

It's possible it is an NEC Code Violation to switch off the Neutral side
in anything of that caliber without switching off the Hot side also., if
it's a Caged Assembly Protected from Unauthorized Access & Personnel, it
passes as a job well done.

Roy ~ E.E.Technician
(Master Electrician)
 
J

John Gilmer

Jan 1, 1970
0
Please define what you mean by "switching the neutral". I made one assumption
about what you meant, then when I read the first reply, it was obvious that
another assumption of something entirely different was possible. So what you
are saying is ambiguous at this point.

Exactly.

He said "commercial equipment."

I mentioned in another thread that when a DVD player I had went south I
opened it up just to see if it was something simple like a fuse. Turns out
that the line switch and the fuse, which was OK, were on the neutral side.
I suspect that since if you don't "open up" the "equipment" it doesn't
really matter which side you switch, the makers don't bother to be uniform.
I suggest that they use polarized line sets just because "sometimes" it
makes a difference.
 
J

Jimmie

Jan 1, 1970
0
| Lately I have come across two cases of switching the neutral in
commercial
| equipment. I had always heard this was a bad thing to do. The only
reason I
| can figure on doing this is to be able to detect a ground fault without
| energising the motors. I this correct?

Please define what you mean by "switching the neutral". I made one
assumption
about what you meant, then when I read the first reply, it was obvious
that
another assumption of something entirely different was possible. So what
you
are saying is ambiguous at this point.

Which of the following is correct?

1. The neutral is being switched along with (in the same mechanism with)
each of the hot wire(s). Is this switch a snap switch, fused
disconnect,
or a circuit breaker?

2. The neutral is being switched to some load while the hot wire(s)
is/are
not being switched.

3. Each of 2 switches of the 3-way variety selects between hot and
neutral
and their commons supply power to a load (usually a light).

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/
http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/
http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------
Hot is always connected to motor and the neutral is switched
 
J

Jimmie

Jan 1, 1970
0
Roy Q.T. said:
I don't think it's correct, many contractors bid the jobs then send
inexperienced mechs to install the works involved & they wire them as
well, so, there is a good possibility it was wired incorrectly.

I've seen many haywire commercial installations that look like crap, i
always mention it to whom ever hired me but I stay away from them if
it's not my installation, lots of them have short circuits and are
poorly grounded if they are grounded at all. If you specialize in that
type of commercial installations, Check out the Codes Thoroughly & Good
Luck.

It's possible it is an NEC Code Violation to switch off the Neutral side
in anything of that caliber without switching off the Hot side also., if
it's a Caged Assembly Protected from Unauthorized Access & Personnel, it
passes as a job well done.

Roy ~ E.E.Technician
(Master Electrician)

Both devices are wired per schematic
 
J

Jimmie

Jan 1, 1970
0
| It's possible it is an NEC Code Violation to switch off the Neutral side
| in anything of that caliber without switching off the Hot side also., if
| it's a Caged Assembly Protected from Unauthorized Access & Personnel, it
| passes as a job well done.

It's definite.

NEC 404.2(B) Grounded Conductors. Switches or circuit breakers shall not
disconnect the grounded conductor of a circuit.

Exception: A switch or circuit breaker shall be permitted to disconnect a
grounded circuit conductor where all circuit conductors are disconnected
simultaneously, or where the device is arranged so that the grounded
conductor cannot be disconnected until all the ungrounded conductors of
the circuit have been disconnected.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/
http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/
http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

Ground wasnt switched just the nuetral. I contacted the manufacturer and
found thast I was correct. This allows a ground fault to be detected without
actually turning the motor on. As far as this being unsafe it is documented
in the equipment lit and only people familar with the equipment should be
working on it
 
E

ehsjr

Jan 1, 1970
0
Jimmie said:
Both devices are wired per schematic
If the switch to which you refer switches the *branch circuit*
neutral wire and not the hot wire(s), it is wrong, per the
NEC. Period.

If it switches a wire inside the utilization equipment, the NEC
rule does not apply.

When you say wired per schematic, I assume you are talking
about the utilization equipment wiring, not the branch circuit
wiring.

Ed
 
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