wiring for swimming pool pump

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  #1  
Old 08-24-13, 11:03 PM
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wiring for swimming pool pump

I'm wiring a pump for an above ground swimming pool. Due to the distance involved (100 ft. run to a 1.5 hp 120vac motor) I plan to pull three #10 AWG type THWN wires to lessen the voltage drop. Is the wire type and size okay and will these fit in a 1/2" PVC conduit?

Also, NEC Article 680.10 specifies PVC conduit burial depth of 18-inches whereas Article 300.5 allows for 12-inch burial for residential use if it's a 20 amp or less GFCI branch circuit. As I have no trencher it would be very difficult to bury this 18-inches. Is 12-inch burial okay since this is a residential 20 amp branch circuit with GFCI protection?
 
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Old 08-25-13, 01:31 AM
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The wire size and insulation type is acceptable and 1/2 inch schedule 80 PVC conduit can accommodate up to four #10 THHN/THWN conductors.

The burial depth is another matter. In all cases where there are multiple provisions of the NEC you must follow the most restrictive provisions. In this case Article 680 takes precedence over Article 300 and the minimum burial depth is going to be 18 inches.

I have not read Article 680 for quite some time but it MAY be possible to bury at a lesser depth IF you have a minimum of 2 inches of concrete completely encasing the conduit AND the top of the conduit is a minimum of 2 inches deep. Please consult Article 680 in its entirety to be certain this concrete encasement is allowed in lieu of 18 inch minimal burial.
 
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Old 08-25-13, 04:23 AM
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680.10 is if for underground wiring within 5' of the inside walls of the pool.
 
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Old 08-25-13, 08:39 PM
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Wirenut1110,
I went back and re-read article 680.10 in view of your response and what you're saying makes perfect sense. My conduit is 6 ft. from the inside pool wall at its nearest point which will allow 12-inch burial per article 300.5 since this is a 20 amp GFCI protected circuit. That's good news!
Thanks for your help.
 
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Old 08-25-13, 08:54 PM
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Furd,
Thanks for the reality check on my selection of wire and conduit. By the way, is it better to run stranded or solid wire on an installation such as this?

Concerning the burial depth, wirenut 1110 pointed out that article 680.10 calling for 18 inch burial only applies when the conduit is closer than 5 ft. to the inside pool wall. Since I'm 6 ft. away, I should be okay with 12 inch burial. That makes it easier.
 
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Old 08-25-13, 09:08 PM
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Go stranded wire for sure and lube it up if you have some bends in the pipe.
 
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Old 08-25-13, 10:11 PM
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Section 300.5 of the NEC covers underground installations. Table 300.5 allows
Residential Branch Circuits Rated 120 Volts or Less with GFCI Protection and Maximum Overcurrent Protection of 20 Amperes
to be buried at no less than 12".

Note 1: All codes is local and the NEC is a model code. It has no authority until and unless it is adopted by a jurisdiction, so determine the requirements of your local jurisdiction. They may have adopted something entirely different. They may have written their own requirement.

Note 2: If this section does apply where you are, the GFCI must protect the buried conductors. It must be provided by the circuit breaker in the panel that protects the feeders for your pump.
 

Last edited by Nashkat1; 08-25-13 at 11:52 PM. Reason: Correct misinformation
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Old 08-25-13, 11:30 PM
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Nashkat1,

What version of NEC are you referencing?

In my 2011 version with reference to Table 300.5 on page 70.138, Row 1 and Column 4 for "Residential Branch Circuits Rated 120 Volts or Less With GFCI Protection and Maximum Overcurrent Protection of 20 Amps" and not show below on other rows, the minimum burial depth is given as 300 mm or 12 in.
 
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Old 08-25-13, 11:53 PM
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Yep. Original corrected .
 
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Old 08-26-13, 11:03 AM
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More pool pump wiring questions

With regard to swimming pool wiring, NEC Article 680.7 allows for cord-and-plug connected equipment to facilitate the removal or disconnection for maintenance or repair. Article 680.12 states the requirement for a maintenance disconnecting means to simultaneously disconnect all ungrounded conductors for all utilization equipment other than lighting. (It is my understanding that the cord-and-plug connection would suffice as the disconnect means if there was only one load such as a pump.) Article 680.21(A)(5) goes on to say that a cord-and-plug connection for pump motors shall not exceed 3 ft. in length and shall terminate in a grounding type plug. Article 680.22(A)(1) says that receptacles providing power for water-pump motors and other loads directly related to the circulation and sanitation system and located within 6 to 10 ft. from the inside walls of the pool must employ, among other things, a single receptacle and a locking configuration plug (i.e. Twist-Lock).

In my case, I have a 1.5 hp circulation pump and ozone sanitation system (ozonator), which must operate together. They each have a 5.5 ft. cord with a 3-prong plug for use with a standard 120 vac receptacle. I had hoped to use a standard 20 amp duplex receptacle with in-use cover supplied from a disconnect device and feeding both the pump and ozonator. These to be mounted 6 ft. from the inside pool wall. However, according to the above references, it doesn't seem that will meet code since the cords are more than 3 ft. in length and do not have locking plugs plus the fact single locking type receptacles would be required.

With that said, it seems my only option is to cut off the standard 3-prong plugs, shorten the cords to 3 ft. (or less) and hardwire to a double-pole on/off switch or standard disconnect device. Probably will need rubber grommets where the cords pass into the switch/disconnect enclosure. I would like to know if my interpretation and proposed solution is correct or if there are other alternatives I might consider.

It seems odd that manufacturers of pool equipment would not provide cords and plugs that meet current code requirements.

Thanks for any help or suggestions.
 
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Old 08-26-13, 12:23 PM
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It seems odd that manufacturers of pool equipment would not provide cords and plugs that meet current code requirements.
It does. Don't rush into anything just yet. I'll try to check a couple of resources, and others with more knowledge may chime in.

it seems my only option is to cut off the standard 3-prong plugs, shorten the cords to 3 ft. (or less) and hardwire to a double-pole on/off switch or standard disconnect device. Probably will need rubber grommets where the cords pass into the switch/disconnect enclosure. I would like to know if my interpretation and proposed solution is correct or if there are other alternatives I might consider.
The odds that the cords on your appliances are rated for use inside an enclosure are between slim and none. I would suggest replacing the cord caps with twist-locks but I'm not sure that wouldn't void the UL listing for the appliances.

More research is needed.
 
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