# Need some suggestions on how to wire this job....



## carlsbad-bird (Jun 14, 2012)

This week I will be wiring up a SquareD Size 2 panel to a motor (water transfer pump). 

Here are the materials:

350' #6/3 direct burial cable (Service run from disconnect to panel)

3/4'' Rigid conduit to motor, stubbed up into a GUAT

#10 Wire from panel to motor

#14 wire from panel to a "head switch".


Basically, the panel will be set, will have 3 phases of 480, a 120V control transformer, and an HOA. It'll most likely always be ran on Auto, so I need a good wiring diagram to set it up since the only "kill'' or "safety" switch will be the "head switch".


Any suggestions on how I should wire it??



ATTACH PICS OF WIRING DIAGRAMS IF YOU CAN PLEASE!! 

THANKS!


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## erics37 (May 7, 2009)

So in Auto, the only thing making the motor turn on and off is the "head switch?"

Is this a hazardous Class 1 location (I'm surmising as much due to the rigid conduit and explosion-proof box)? If so I wouldn't be running 120 volts for controls into the location without an intrinsically safe barrier of some sort.

If not, then it should be easy enough, just run the Auto loop through the switch. You'll need a disconnecting means of some sort within sight of the motor.


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## carlsbad-bird (Jun 14, 2012)

erics37 said:


> So in Auto, the only thing making the motor turn on and off is the "head switch?"
> 
> Is this a hazardous Class 1 location (I'm surmising as much due to the rigid conduit and explosion-proof box)? If so I wouldn't be running 120 volts for controls into the location without an intrinsically safe barrier of some sort.
> 
> If not, then it should be easy enough, just run the Auto loop through the switch. You'll need a disconnecting means of some sort within sight of the motor.



Yeah it's Class 1..... And yes, the head switch is the only thing making it run or turn off at it's set points.... I guess I could just supply the power for the head switch off of the control transformer and then run the kill wire into the back of the contact on my HOA "Hand-Off-Auto"???


Care to whip up a quick diagram of what YOU would do? 

Thanks buddy!:thumbup:


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## erics37 (May 7, 2009)

Is it a submersible pump? What is the "head switch" thing anyway?


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## carlsbad-bird (Jun 14, 2012)

erics37 said:


> Is it a submersible pump? What is the "head switch" thing anyway?



It's a shaft driven pump, attached to a yoke that is spun by a 3 phase, 480V 15HP motor......


The head switch is basically just a "kill switch" that measures water levels in a tank; it can be wired N/O or N/C.... The operator, or myself, will set the "high kill" at, say 8', so that when the level needle makes contact, it will engage the pump, causing the pump to pump away the water, dropping the water level.... After it has dropped to the "low kill", say 3', the needle makes contact and it then turns the motor off......


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## erics37 (May 7, 2009)

carlsbad-bird said:


> It's a shaft driven pump, attached to a yoke that is spun by a 3 phase, 480V 15HP motor......
> 
> 
> The head switch is basically just a "kill switch" that measures water levels in a tank; it can be wired N/O or N/C.... The operator, or myself, will set the "high kill" at, say 8', so that when the level needle makes contact, it will engage the pump, causing the pump to pump away the water, dropping the water level.... After it has dropped to the "low kill", say 3', the needle makes contact and it then turns the motor off......


Okay well if you've got a switching mechanism in the Class 1 Div 1 location running 120 volts through it then the switch loop's gotta be run through an intrinsically safe barrier.

I'd try to mount the disconnecting means and starter/control enclosure outside of the Class 1 boundary so I wouldn't have to make it explosion proof, then you'd just have a conduit or two containing motor leads and switch loop with some seal-offs.

Otherwise it's just a basic HOA setup. Unless you're leaving something out, then this is one way to do it:


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## carlsbad-bird (Jun 14, 2012)

erics37 said:


> Okay well if you've got a switching mechanism in the Class 1 Div 1 location running 120 volts through it then the switch loop's gotta be run through an intrinsically safe barrier.
> 
> I'd try to mount the disconnecting means and starter/control enclosure outside of the Class 1 boundary so I wouldn't have to make it explosion proof, then you'd just have a conduit or two containing motor leads and switch loop with some seal-offs.
> 
> Otherwise it's just a basic HOA setup.  Unless you're leaving something out, then this is one way to do it:




AWESOME! THANK YA!!!



BTW, I was already planning on mounting my panel outside of my Class 1 barrier. Saves a lot of work and all I have to do is run conduit, tie in one GUAT, and 2 EYS fittings. Thanks again!!!


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## erics37 (May 7, 2009)

carlsbad-bird said:


> AWESOME! THANK YA!!!
> 
> 
> 
> BTW, I was already planning on mounting my panel outside of my Class 1 barrier. Saves a lot of work and all I have to do is run conduit, tie in one GUAT, and 2 EYS fittings. Thanks again!!!


Well don't forget the IS barrier, even if your control panel is outside of the classified location, the actual switching mechanism isn't. If you're running 120 volts through it, it's entirely capable of carrying enough energy to arc when the switch actuates. You don't want sparks to happen.


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## carlsbad-bird (Jun 14, 2012)

erics37 said:


> Well don't forget the IS barrier, even if your control panel is outside of the classified location, the actual switching mechanism isn't. If you're running 120 volts through it, it's entirely capable of carrying enough energy to arc when the switch actuates. You don't want sparks to happen.



Oh it'll have the IS barrier. I'll also be installing a Siemens Overload setup, lightning arrestor, and phase monitors. Also have to install a lease kill and an extra set of panduit just in case they decide to put in a SCADA system, power supply, and anything else.... HaHa


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## don_resqcapt19 (Jul 18, 2010)

erics37 said:


> Okay well if you've got a switching mechanism in the Class 1 Div 1 location running 120 volts through it then the switch loop's gotta be run through an intrinsically safe barrier. ...


 Can you cite a code section that says that? You can install 120 volt controls in Class I, Division 1 locations by using explosionproof enclosures. You can install 120 volt controls in Class I, Division 2 locations by using sealed switches without explosionproof enclosures.


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## erics37 (May 7, 2009)

don_resqcapt19 said:


> Can you cite a code section that says that? You can install 120 volt controls in Class I, Division 1 locations by using explosionproof enclosures. You can install 120 volt controls in Class I, Division 2 locations by using sealed switches without explosionproof enclosures.


I don't have a code section for it, just what I always do.


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## don_resqcapt19 (Jul 18, 2010)

erics37 said:


> I don't have a code section for it, just what I always do.


 Can you give me a link to an IS barrier suitable for 120 volt controls? I don't see how that is even possible. 

As far as the code section, you won't find one that says you have to use IS circuits for controls in Class I locations. There are other protection methods that are suitable for Class I locations.


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## erics37 (May 7, 2009)

don_resqcapt19 said:


> Can you give me a link to an IS barrier suitable for 120 volt controls? I don't see how that is even possible.
> 
> As far as the code section, you won't find one that says you have to use IS circuits for controls in Class I locations. There are other protection methods that are suitable for Class I locations.


Sorry, I don't know what I'm thinking. I'm programmed for "Switching mechanism in class 1, intrinsically safe it." Didn't put 2 and 2 together. Thanks for the tips.


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## carlsbad-bird (Jun 14, 2012)

I wound up setting my panel OUTSIDE the barrier, running pipe underground into the barrier, stubbing up to the motor with an EYS and GUAT and running to the motor, stubbing up, EYS, GUAL and hard pipe into the motor. 

And I added a Pentra PLC with a LDR program for it all and added a few extra I/Os in case they decide to add a pressure switch and a togge for the motor. 

Thanks


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