# Wiring Suggestions



## dawgs (Dec 1, 2007)

We are installing the power wiring for a sewer grinder pumps system. The pumps are 240V single phase and we only have a 120/208 3-phase panel close by. Would you guys wire it for the 208 single phase or install a step up transformer to get the 240V thats recomended.


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## MDShunk (Jan 7, 2007)

Grinder pumps need all the help they can get, so I probably wouldn't wire them at 208 unless the dataplate lists that in the range the motor can handle. If they're straight 240, I'd absolutely install a buck-boost for it (or, order the right pumps and send these back).


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## dawgs (Dec 1, 2007)

The pumps are 120/240. Not sure if they are rated for a lower voltage. Just wondering what the life span may be by wiring them at 208V.


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## John Valdes (May 17, 2007)

dawgs said:


> The pumps are 120/240. Not sure if they are rated for a lower voltage. Just wondering what the life span may be by wiring them at 208V.


If the nameplate on the motor does not say 120/208/240, then they are not rated for 208. Be very careful. Should you burn one of these motors up and they find out you connected to 208, there will be no warranty replacement. You eat it. Try to get the right motors or the right voltage. Be very careful. 

Running the motors at 208 will shorten the life, but no one knows how short or how long.


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## dawgs (Dec 1, 2007)

Just found the manufacturers instructions on line and they suggest a minimum of 216V. Pumps are already with the system on site so I guess I will just supply a transformer.


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## micromind (Aug 11, 2007)

In my experience, the vast majority of motors marked 230 or 240 volts will work on 208. 

The most notable exceptions are any type of submersible pump. Sewer pumps, well pumps, etc. These run so close to their rated HP that there's just no room for low voltage. 

Most of these motors are operated in their service factors, the actual current is actually slightly higher than the rated full-load current, but lower than the service factor amps (SFA). 

As stated above, I would install buck-boost transformers to get the voltage up to 240.

Rob


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## leland (Dec 28, 2007)

Yup. Factory 'skid unit'- give the correct voltage- Vote for Trani.


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## InControl (Mar 20, 2007)

micromind said:


> In my experience, the vast majority of motors marked 230 or 240 volts will work on 208.


I ditto that. There is no 240V in the plant where I work and we have been running 240V motors on 208V for 15+ years.


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## Jlarson (Jun 28, 2009)

Go with the 240V step up. Like MDShunk said grinder pumps need all the power they can get. 

I had two the other day that were sucking so much stuff threw they were pulling 2 extra amps the almost tripped their OLs and flooded the whole lift station. I would say if these pumps were running on a lower voltage they probably would have tripped.


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## dawgs (Dec 1, 2007)

Thanks for the replies. A transformer it is.


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## micromind (Aug 11, 2007)

A buck-boost transformer will be far less expensive than a full-rated one. And light enough to be installed by one person.

Rob


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## william1978 (Sep 21, 2008)

dawgs said:


> Just found the manufacturers instructions on line and they suggest a minimum of 216V. Pumps are already with the system on site so I guess I will just supply a transformer.


 Sounds like a change order to me.:thumbsup:$$$$$


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## dawgs (Dec 1, 2007)

william1978 said:


> Sounds like a change order to me.:thumbsup:$$$$$


 I will just absorb it. It is for a mechanical contractor that has gotten us a lot of industrial work, as they work in a lot of different plants and use us for all their electrical.


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## John Valdes (May 17, 2007)

Have you ever used a an aluminum wound transformer. Great price and good quality. You may make more on the job if you were to consider this. I would the use an AL xfrm and not look back.


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## sparky105 (Sep 29, 2009)

good rule of thumb is +10% & -15% that was from an engineer I know and a lot of data sheets That I have read.


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## MDShunk (Jan 7, 2007)

John Valdes said:


> Have you ever used a an aluminum wound transformer. Great price and good quality. You may make more on the job if you were to consider this. I would the use an AL xfrm and not look back.


I probably have and didn't know it. I've never specially spec'd one that way.


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## sparks134 (Jan 30, 2009)

you need to install a step u transformer!


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## sparky970 (Mar 19, 2008)

dawgs said:


> The pumps are 120/240. Not sure if they are rated for a lower voltage. Just wondering what the life span may be by wiring them at 208V.


Why not wire it for 120V?


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