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Kevin
Kevin, Licensed Electrical Contractor
Category: Electrical
Satisfied Customers: 3721
Experience:  30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License
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I have a 1.5 HP submersible 3-wire pump that is about 500 feet

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I have a 1.5 HP submersible 3-wire pump that is about 500 feet into the ground. Can you please tell me what wattage generator I will need?

Hello.....my name is XXXXX XXXXX I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!

 

1) Is the pump a 240 volt single phase motor?

 

2) Do you have the nameplate rating on the motor? Can you provide me with the Full Load Current or FLA rating?

 

 

 

Customer: replied 4 years ago.

Hi, Kevin.....this pump was installed 20 years ago. It was a "Goulds" submersible but I notice reference to "Franklin Submersible motors. I looked through my complete file and the only thing I know for certain is that the Model number is (was) 7EH15-412. I know that does not give you much to go on, but, unfortunately, that's all I have. It would be impossible for me to try to pull up the pump to read the nameplate rating.

Hello George.....Thank you for the replies....2 more quick questions as follows:

 

1) Is the circuit breaker for the pump protected by a single pole or a double pole breaker? I need to know if this is a 120 volt or a 240 volt? I assume it is a 240 volt and is installed at a house and not at a commercial or industrial environment?

 

2) Are you looking to use a portable generator or a standby generator to provide emergency power to the pump?

 

Customer: replied 4 years ago.

You're terrific, Kevin.....to ask such detailed questions. It shows you really care to get it right.


 


Yes, the pump is installed at a house. (that's easy). If you can tell me what to look for, I can go down to the basement and look at the circuit breaker box to determine if I can distinguish between a single or double pole breaker.


 


Yes, all I'm looking for is a mobile generator for the (almost exclusive) use of getting water in case power is cut for more than a few days.

1) Look at the directory of your main electrical panel and locate the circuit breaker for the pump. The breaker will either be a single pole or a double pole breaker (most likely it will be a double pole breaker with a common handle tie going across the breaker such as the one shown below).

 

Attached is a picture of a 240 volt double pole breaker. If it is a single pole breaker, the size will be half of the double pole breaker.

 

Also, let me know the amperage rating located on the breaker.

 

graphic

Customer: replied 4 years ago.

Hi, Kevin-


 


Yes it is a double pole breaker and there is a number "30" that is etched into each of the two ends of the pole

1) Thanks George, just as I suspected. That is a 240 volt motor on the pump protected by a 30 amp double pole breaker.

 

2) If you apply Watts Law where P = I x E (P = Watts, I = Current and E = Voltage)

 

P = I x E = 30 x 240 = 7,200 Watts or 7.2kW.

 

3) To support this amount of current for the pump, you would require a generator capable of 240 volts and a minimum of 7,200 watts or 7.2kW.

 

4) 7500 watt generators are the common wattage rating in this size. Attached is a link to Home Depot. Generac and Rigid are both quality brands. These are in the $1000 price range.

 

http://www.homedepot.com/webapp/catalog/servlet/Search?storeId=10051&langId=-1&catalogId=10053&keyword=portable+generator&Ns=None&Ntpr=1&Ntpc=1&selectedCatgry=Search+All#/?c=1

 

 

 

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

 

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!



 

Customer: replied 4 years ago.

It certainly helps, Kevin......you've given me the exact information I need and after giving it considerable thought. I'm just wondering whether the 7500 is the "running" wattage" or does it also include the "surge" requirement?

1) The 7500W is the running wattage. All portable generators will also have a surge wattage listed on the generator. Typical surge wattage on a 7.5kW generator will be at approximately 9kW.

 

2) Your pump actually requires 25 amps under Full Load Current. Based upon the tables in the National Electrical Code (NEC), a 1.5 HP motor at 240VAC Single Phase, the FLA rating is 10 amps. The NEC says to size the breaker at 250% of the FLC. Therefore, 250% or 2.5 x 10 amps = 25 amps. The 25 amp value compensates for the "in-rush" current. A 25 amp breaker is rare to purchase, therefore the code allows to have the breaker as the next higher standard size which is a 30 amp double pole breaker. Therefore, the 7500 running wattage will handle the initial "in-rush" or surge current upon pump start-up.

Kevin and other Electrical Specialists are ready to help you

George......Thank you for the excellent service rating..............much appreciated!

 

If you have any other questions, just let me know.

 

Take care and have a great evening..............Thanks..............Kevin!

Customer: replied 4 years ago.

Kevin....you deserve all the thanks. You took a difficult question with very little information and worked around it with a dolt like me till you knew enough to give me an answer I couldn't get from anyone else. The small fee for this kind of service is a real bargain..


 


Thank you for your patience and God Bless You.

George...... thank you much for the kind words... much appreciated!

 

If you have any other questions about the generator, just reply back to this question and I'll be more than happy to assist you. No need to create another question. I am logged on here at JA every late afternoon and evenings as well as on/off most weekends.

 

As you can probably tell, I enjoy assisting my customers whether they are for my electrical contracting business or on Just Answer. I love performing electrical work and helping anyone. I was previously employed as an adjunct electrical instructor at Northern Illinois University and at the University of Illinois and they stopped the Construction Management certification classes back in 2007 due to the housing market downfall that we have all encountered. In addition to being a licensed electrician for 26 years, I'm also a Certified Construction Manager for new single family dwelling construction. Thus, being able to assist customers here on JA, is my way to still be involved with teaching.