Pool Wiring Questions

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Old 06-23-16, 11:39 AM
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Pool Wiring Questions

Preparing to run conduit/wire for my pool, but I have a few questions before getting started.

I have acquired the following materials:

500ft 10 gauge THHN/THWN (3 spools black/white/green STRANDED (is this OK??)
3/4" PVC SH40 conduit/boxes
20AMP GFCI (convenience outlet)
20AMP L5-20 (pool pump)
20AMP switch (pool pump)

Questions:

Since I am using 10 gauge wire, do I need to up the breaker to a 30amp? I chose 10 gauge due to the distance to the pool which is 110ft, and I wanted to account for voltage drop - my pump runs at 115v 2.9/11 AMPS (2 speed pump). I used the Southwire voltage drop calculator and it said 12 gauge was only good up to 90ft.

I will be transitioning from my house to the conduit using a 3/4" LB, my cities "pool packet" says I can use romex OR THHN inside the house, if I choose to use romex, does it also need to be 10gauge?

FYI Everything will be permitted and inspected, I would just like to get everything to code so I have no hiccups - pool is going up July 1st/2nd, and would like to have it usable for the 4th!

Thanks all!
 
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Old 06-23-16, 12:26 PM
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500ft 10 gauge THHN/THWN (3 spools black/white/green STRANDED (is this OK??)
Yes. No, that would be a code violation. A 20amp receptacle can't be on a 30 amp circuit.
I used the Southwire voltage drop calculator and it said 12 gauge was only good up to 90ft.
Using number 12 you would have a 4% voltage drop so it is border line. Since motors have high starting current the #10 is probably best.
if I choose to use romex [in the house0, does it also need to be 10gauge?
I'd use #10 but #12 would be okay.

You will need in use covers for the receptacles and switches.
 
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Old 06-23-16, 12:36 PM
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Ray, thanks for responding. I didnt think I should use the 30amp breaker, just wanted to make sure I wasnt running into trouble if someone saw the 10 gauge wire and assumed it was a 30 amp breaker. I do have 2 "in-use" covers for the GFCI and Twist lock, and I have a weatherproof switch cover for the switch to the pump like below:

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Old 06-23-16, 02:09 PM
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The plan sounds OK. Make sure to get your clearances right. The twist lock pump receptacle can be no closer than 6' from the pool rim; the general-purpose GFCI receptacle can be no closer than 6' and no further than 20' from the rim.

Also make sure to get all of your bonding right.

Are you using a GFCI breaker on the pump circuit?
 
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Old 06-23-16, 02:26 PM
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ib

We are at least 12ft from all fence lines and both receptacles will be 6.5ft from the pool wall. We are also 12ft from the nearest power line/utility lines. I ordered the Burndy in-skimmer plate and 2 - 3pack Burndy lugs along with 115ft of 8 gauge solid bare copper to go all around the pool continuously.

Our cities pool packet show you can use the same circuit that the GFCI plug is on, so we were going to wire it Main Panel > GFCI > Switch > Twist Lock. We were going to skip the GFCI breaker due to the GFCI plug, is that not correct?

I see you are in MI - I'm in Warren.

Cities diagram:

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Old 06-23-16, 03:10 PM
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Sounds like you have it covered. Enjoy the new pool. I'm in the Lansing area.
 
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Old 06-26-16, 02:54 PM
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So question, and this answer may be dependent upon our inspector:

Can we use LFMC to run the wires out to the pool?

Reason I ask, we rented a trencher that was suppose to dig 18", well it only dug out 15"ish. That prohibits the use of the PVC conduit. We were going to purchase rigid conduit and bury at 6", but our trench line is not exactly straight and I have ZERO experience with a pipe bender. So while at the store we found LFMC - Liquid Tight Metallic Flex Conduit.

Also, if we can, what burial depth am I looking at?

Thanks!
 
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Old 06-26-16, 03:57 PM
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LFMC can be buried, however at 110' don't even consider it,why not just hand dig the additional 3" or so in the trench,use a pick to loosen the dirt.
 
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Old 06-26-16, 05:02 PM
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It would still be 18" under NEC table 300.5 column 3 (if the trench is filled with dirt) http://www.google.com/url?sa=t&rct=j...5RtNo55jAnshTA or do you have another reference?
 
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Old 06-26-16, 05:40 PM
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Ray

I do not have another reference, and I was looking at that chart but was confused as Column 2 says 6" for Rigid or IMC (which I cant find at the box stores) and Column 3 says "nonmetallic". The LFMC states it IS metallic with a PVC jacket - does this still constitute as "nonmetallic"?

I am aware of the 6ft rule per the NEC 2011, but noticed in NEC 2014 they removed it. Also, I would still be using 3 THHN/WN conductors and would NOT be using the metal jacket as a ground.

If I have to dig, I will, just wasnt looking forward to it after dragging the trencher 100ft, and then having to rent a jackhammer to break up a concrete wall under the back yard, and yes, it ran the width of the yard - old boundary line from like 50 years ago!

Edit - also, does it make a difference if I install a GFCI breaker rather than relying on the GFCI Convenience outlet? Per Column 4.
 
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Old 06-26-16, 05:50 PM
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IMC and RMC are both threaded pipe like conduit. LFMC because of cost is just not used normally for direct burial for more then a few feet.

However there is a simple cheap solution that should require no extra digging if your inspector approves. Use a GFCI breaker and the burial depth is one foot for a 120 volt 20 amp feeder so you could use PVC conduit. See column 4.
 
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Old 06-26-16, 06:01 PM
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Ray

thanks, I'll call and see if I can do this in the morning.
 
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Old 06-27-16, 07:34 AM
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Just to update this, I talked to the inspector today and he approved 12" cover with GFCI protection for the entire run. He said I could do a GFCI breaker or a GFCI outlet on the back of the house.
 
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Old 06-27-16, 10:46 AM
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Sure makes your job a lot easier,have fun!
 
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Old 06-27-16, 10:58 AM
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Thanks Geo - and that it does. Was very relieved to hear the inspector say it was Acceptable!
 
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Old 06-27-16, 12:23 PM
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The LFMC is like a grey flexible metal condust called Greenfield, but it also has a coated outer jacket. There is another product called LFNMC that is nonmetallic and looks like grey garden hose.
 
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Old 06-29-16, 09:41 PM
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And back again...

My plan is to bring the THWN into the house via a LB conduit body, then a short piece of conduit to a metal junction box mounted in the rim joist. Last winter we insulated the rim joist with 2" rigid foam. If i use long enough screws to hit the rim joist, is it OK to place the junction box ON the rigid foam?
 
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Old 06-29-16, 10:39 PM
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Is the box going to contain a GFCI receptacle (or dead face)? If so will it be easily accessible? If so then probably no problem if it gives you a firm mount or screew on a larger piece of plywood first then the box to the plywood.
 
 

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