Switching neutral in 120v control

[electromike]

Does anyone have experience with switching the neutral instead of the "Hot" conductor in control circuits except in motor starter buckets. I have encountered this practice on a DCS system in a chemical manufacturing facility.I am told this is a safer practice in that all conductors in the field are already a grounded conductor and any shorts to ground will only switch "on" the respective circuit. I would like some input on this concept if anyone knows some specifics. Thanks.

 

[waross]

If and when I come across my 1956 edition of the Canadian Electrical Code I'll check but I am pretty sure that the rule and practice was firmly established at least 50+ years ago. A long time ago when I was young I spent some time doing rewires on very old houses. It was very unusual to find a switched neutral. If one was found there was usually evidence that it was not original wiring but a modification.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zappedagain]

I don't know where I learned this misinformation, but I know it was long ago. Luckily I've only moved to more system design a few years ago, so I only have this crossed wiring in 20 systems; I can fix them as the come in on RMA. I wonder if UL would catch this when the system goes in for testing.

I did a web-search on this topic and it is amazing how much info pops up that switching the neutral is correct; scary. Luckily most of the entries also get corrected after a while.

Zapped

 

[automatic2]

don't forget that a neutral only exsists in at least a 3 wire circuit. Many control circuits are isolated two wire cicuits that may or may not be grounded.

 

[davidbeach]

In this case neutral is what the NEC refers to as the "grounded conductor". No need for three phases or a wye system.