# Relay for 220 volt line and CODE



## cathead (Jan 20, 2015)

Hello everyone, 

Having wired up my single phase 220 volt  VFD with a DPST relay by 
just breaking L1 and L2 and not the ground, I'm wondering if I need to 
break the ground as well using a TPST relay to conform with 
electrical code.  It works fine as is.........and I am happy with it BUT
as far as code goes, not sure. 


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## davidh (Jan 20, 2015)

opinions are like 'you know" but i think the ground should also be disconnected.  i had a ground that actually had been erroneously made hot by another incorrectly wired device, when i went up a aluminum ladder to move some wires, dam near knocked me off the ladder.  everything else worked fine in the system up to that point.  rude awakening. . . for sure.
i am not, however, an electrician, but have done lots of wiring in my day.,


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## arvidj (Jan 20, 2015)

Another non-electrician opinion.

Never "switch" the ground. To do so would imply that there would be situations where 'the switch would be open, either intentionally or by switch failure' and the device would not be grounded.

Just switch L1 and L2.


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## John Hasler (Jan 20, 2015)

cathead said:


> Hello everyone,
> 
> Having wired up my single phase 220 volt  VFD with a DPST relay by
> just breaking L1 and L2 and not the ground, I'm wondering if I need to
> ...



Do you mean the ground (green wire) or the neutral (white)?  They are not the same thing.  You should never, ever, *ever* switch the ground.  It's rarely necessary to switch the neutral.  The neutral should also never, ever *ever* be connected to ground in the equipment.


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## JimDawson (Jan 20, 2015)

+ 1 what arvidj said.  I have never seen a code that requires a switched ground, and that doesn't seem safe.  The experience that davidh had on the ladder is very strange, and the result of a grossly miss-wired system.  That one means that there actually was no ground at all.  I have seen this problem in very dry climates where the ground moisture is so low that it wasn't really possible to get an earth ground, but this is not common.

For normal operation and maintenance, disconnecting the power wires via the provided disconnect is normally adequate.  This still requires that the person performing maintenance do a proper voltage check to confirm that the system is in fact dead.  If major maintenance is to be performed on the machine, then a complete disconnect of the incoming wiring might be in order.


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## davidh (Jan 20, 2015)

"never does a day go by" as the saying goes.   i just had a conversation with my electrical friend, he said just opposite of what i posted earlier.  i went and checked my actual grounding and found my ground wire has actually broken free from the ground rod.  lawn mower ?  animal ?  me ?
sorry for the incorrect info. .


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## cathead (Jan 25, 2015)

I was a bit confused and actually was referring to switching the neutral, 
not the ground.  Anyway I am switching the L1 and L2 and not the neutral or ground. 
It works fine and the neutral line is grounded at the main 200 amp service.  Thanks
everyone for weighing in on the subject.


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## compressorguy (Jan 25, 2015)

cathead said:


> I was a bit confused and actually was referring to switching the neutral,
> not the ground.  Anyway I am switching the L1 and L2 and not the neutral or ground.
> It works fine and the neutral line is grounded at the main 200 amp service.  Thanks
> everyone for weighing in on the subject.



Just wondering, unless it is to provide 110v to controls, why do you have neutral on a 220v machine?

Regards

Gary KB7GRH


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## cathead (Jan 25, 2015)

Gary, 

I'm using a 110 volt relay and also a 110v transformer with a bridge rectifier to produce
12 volts to run the fan and pilot light bulb.    


QUOTE=compressorguy;268890]Just wondering, unless it is to provide 110v to controls, why do you have neutral on a 220v machine?

Regards

Gary KB7GRH[/QUOTE]


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## compressorguy (Jan 26, 2015)

cathead said:


> Gary,
> 
> I'm using a 110 volt relay and also a 110v transformer with a bridge rectifier to produce
> 12 volts to run the fan and pilot light bulb.
> ...



That explains it then!  

G'day

Gary KB7GRH


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## Wireaddict (Jan 28, 2015)

Just a suggestion: if one of the 220/240V wires you're switching happens to be white, mark it black, red or some other color [except green which=ground conductor] with tape, paint, nail polish, magic marker, etc., so it won't be mistaken for the neutral wire.


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