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Kevin, Licensed Electrical Contractor
Category: Electrical
Satisfied Customers: 3531
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'm installing power on my new property. From the power drop

Customer Question

I'm installing power on my new property. From the power drop at the pole I have a single phase 200 amp main panel and I'm running about 130 ft to my 200amp sub panel which is outdoors freestanding and not attached to a building.
Would I be correct in running (2) 3" conduit with (3) 4/0 aluminum wires in each conduit? Also, what size ground do I need in each?
From the sub panel I'm runnng 1 1/2" conduit 230 ft to the well/pump which is a deep well with a 1 1/2 hp pump on 220V. What size wire do I need to run for the 230ft? Would (3) #4 copper with a #10 copper ground be correct?
Thank you!
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) The sub-panel feeder circuit requires a 4 wire circuit comprised of 2 hots, 1 neutral and 1 equipment grounding conductor. Yes, 4/0 aluminum conductors are required and will result in a 1.8% voltage drop or a loss of 4.4 volts. National Electrical Code recommends the voltage drop be 3% or less. Therefore, the 4/0 aluminum is OK. If installing the feeder circuit in PVC conduit, the equipment grounding conductor needs to be sized as a minimum of 4 AWG aluminum.

2) All 4 sub-panel feeder conductors can fit inside (1) one 2" diameter gray electrical PVC Schedule 40 conduit. Although to make the wire pull easier, I recommend to increase the conduit to either 2 1/2" or 3" diameter. Bury the sub-panel feeder conduit run a minimum of 24" below final grade.

At the sub-panel, you will need a quantity of (2) two 8 foot ground rods spaced a minimum of 6 feet apart. The grounding electrode conductors at the rods needs to be sized as 4 AWG copper.

3) A 240 volt single phase motor that is 1 1/2 hp has a full load current of 10 amps. Due to the "in-rush" current, the minimum breaker size is sized at 125% of the FLA rating. Therefore, 1.25 x 10 amps = 12.5 amps. Round up to the next available trade size breaker and use a 15 amp double pole breaker for the well pump.

4) The 230 foot well pump run requires 8 AWG copper for the 2 hots and (1) one 10 AWG copper for the equipment grounding conductor. If using PVC conduit for the well pump, minimal diameter pipe is 1/2". In order to make the wire pull easier, I recommend to install 1" conduit. The voltage drop on 240 volts/15 amps on a 230 foot run results in 2.2% voltage drop or a loss of 5.2 volts which is code compliant and therefore OK.

5) Since the 200 amp sub-panel will be installed outdoors and exposed to the elements, it needs to be rated as a minimum of a NEMA 3R (waterproof type) panel. Install a 200 amp sub-panel that has a 200 amp main breaker and not a main lug type of panel.

6) All feeder and branch circuit conductors need to be rated as type "THW" for wet conditions.

7) Install a warning ribbon tape directly above the sub-panel feeder trench and the well pump trench. Bury the warning ribbon tape approximately 6" below final grade level on the entire conduit/trench run to provide a warning that anybody digging and/or trenching in the future that an electrical line exists directly below.

8) At the sub-panel, DO NOT install the green main bonding screw or a main bonding jumper strap. On all sub-panels, the neutral must remain isolated from the panel metal enclosure., By not installing the main bonding jumper is how the neutral remains isolated. At the sub-panel, you will need to install a separate equipment ground bar for the equipment grounding and grounding electrode conductors. DO NOT inter-mix white neutrals and grounds on the neutral bus bar. Neutrals only land on the neutral bus bar and grounds only land on the equipment ground bar in a sub-panel.

9) Identify both conduit runs by pounding either metal stakes in the ground and spray painting them with a red color and/or reference the conduit run dimensions from corners of the building and/or power pole structures and/or the property easement/boundary lines. Document both conduit runs with the appropriate dimensions for future reference and create an "as-built" drawing in the event future digging near these areas need to occur. Make a copy of the "as-builts" and tape them inside the respective electrical panels for future reference.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

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


Expert:  Kevin replied 1 year ago.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

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


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