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.
| 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?
You don't switch the neutral because you expect the white wire to be de-energized. If you switch the neutral, when the switch is open the white wire on the line side will be hot and bite the piss out of you.
Jimmie wrote:
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)
When you wire a load you go from the line to a switch, to the load then to grounded neutral. With the switch open the load is at ground potential.
If you go from the line to the load then switch then to grounded neutral, the switch will turn off/on the load but the load connections will always be hot. With the switch open the load is at line potential.
The switch works as expected in both situations.
If you are lucky you can find this out with your tester. If you are unlucky you find this out with your hand.
Roy Q.T. wrote:
| 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.
No Kidding? I know how to wire them I just don't like what I find when someone else has wired them., specially if they switched the neutral., Of Course it will start/stop the motor/device from operating but it is not the Correct way to switch anything., it leaves the amarture Hot even with the switch n the Off Position., I'm Never Lucky, I'm a Skilled & Professional Technician & I never appoach another persons work without due observations & tests. =AEoy
From:(Kilowatt) When you wire a load you go from the line to a switch, to the load then to grounded neutral. With the switch open the load is at ground potential. If you go from the line to the load then switch then to grounded neutral, the switch will turn off/on the load but the load connections will always be hot. With the switch open the load is at line potential. The switch works as expected in both situations. If you are lucky you can find this out with your tester. If you are unlucky you find this out with your hand. Roy Q.T. wrote: 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)
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.
Ok, maybe a garbage disposal, but it is rare.
Ok and a fan. Maybe it is not so rare after all.
No Kidding? I have never seen a motor controlled by a switch. How many have you wired?
Really??? Just what are the motors in your car controlled by? Wipers and starters come to mind.
In the SW swamp coolers on normal light switches in the old days were the norm. Break one leg and feed the motor with 240v. No t-stat, just a switch on the wall. You were high tech if you had a rotary switch for high speed, low speed , pump and vent. Now days the t-stats do all of that.
Hot is always connected to motor and the neutral is switched
Both devices are wired per schematic
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
|> | 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 |
Switching the neutral is not necessary to detect ground faults; it's just the cheap way to do it. This thing should not be sold to the public.
Of course; There may be a difference when you wire stuff according the specs and when you wire it conventionally., if any equipment is supplied with detectors, monitoring devices etc. it may be advisable to wire it differently for Maximum Convenience and Performance, but it still must be Installed up to code. The Equipment in question here, as Jimmie stated, is not conventional & is Compliant wit the NEC as long as & ONly if it is Kept Inaccessible to Unauthorized Personnel as in a Caged & Locked Area or Compartment as I had mentioned earlier in the thread. =AEoy
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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