above ground swimming pool wire size question

[bob15]

Going to helping my Brother with his above ground swimming pool.

The pump is 2 hp, 115v
Distance from main circuit panel to where he wants to go out of the house is between 80-100 ft
Distance from house to pool ~25 ft max

One thought was to run 6/2 w/ground romex from circuit panel to about where the hole will be for going out of the house, add a junction box and run liquidtite from box, through wall, underground to GFCI outlet 6 ft from the pool. Inside the liquidtite would be three 6ga THWN wire.

My question is: if the 6 gauge inside the conduit needed, how do I install it onto a outlet? Buy a double gang box (for the working room) and pigtail the 6ga to stubby 12 ga and attach the 12ga to the outlet?

Or would running liquidtite and the THWN wire from the circuit panel to the pump outlet be a better option?

 

[Terry D]

# 6 is way over kill. If it is a real 2 hp motor, per the NEC table is 24 amps x 1.25 = 30 amps. So # 10 will work Can you wire it for 240, if so you can use #12. I dont know your codes in your area, but i will tell you how we wire a above ground pool. Its pretty much right out of the NEC.

A bond ring using # 8 bare copper ground must originate from the lug on the pump, connect to a water bonding fitting usually in the basket strainer ( this is something you have to install, doesn't come with the pump ) then continue around the pool and connect to form a ring. The bonding ring has to be 18 to 24 inches from the pool wall and be 4 to 6 inches deep. It must also connect to the pool structure 4 times, equally spaced. Ladders these days are all plastic, but if metal, it would have to connect to the bonding ring.

The wiring inside the house can be NM-b, but anything outside has to have a insulated EGC. So underground we use PVC conduit and THWN conductors. We are not allowed to use liquidtite for those distances. If you are allowed to use it for that distance, it has to be listed and marked for underground.

The cord on the pump can only be 3 ft. the receptacle has to be 6 ft away from the pool wall. The plug and receptacle has to be a twist lock. So for your GFCI protection, you would need a GFCI breaker or they way I do it is use a dead front GFCI out at the receptacle. I usually mount everything to a 4x4 concreted in the ground. I usually conduit up into a box for the dead front GFCI and then up to a box for the twist lock. They make a large inuse cover for this. If you decide to wire for 240 volt, then you would have to use a breaker.

 

[bob15]

My reasoning for # 6 was because of the distance of ~130 feet from panel to outlet and basing a 2 hp motor on 24 amps. The calculator/charts I read were between # 6 & # 8, so I would rather up-size it.

I have used underground-labeled liquidtite in the past for my generator, but it is up to my Brother as to what he wants.

Thanks for the bond ring explanation, I wasn't quite sure about it as I don't believe the pool we had some 40 years ago had one.

 

[Terry D]

your distance is 105 to 125 ft. I really didn't do a VD calculation, I would think # 10 would be fine. A lot of times those online calculators are not right. Plus think about how your going to connect that #6 to a receptacle. Can you wire the pump for 240 volt

 

[bob15]

your distance is 105 to 125 ft. I really didn't do a VD calculation, I would think # 10 would be fine. A lot of times those online calculators are not right. Plus think about how your going to connect that #6 to a receptacle. Can you wire the pump for 240 volt

I'm not sure if I can go to 240 as I haven't seen the pump and am going off of what I was told. I think it is the one below, but I cannot confirm it and he is currently with my nephew and little league tonight (and I'm about 50 minutes away, so I am going to wait).

I understand connecting # 6 to an outlet...not going to happen which is why I thought I would have had to put a 10" pigtail jumper on it, but I would think that would be against code

https://www.namcopool.com/waterway-2hp-2-speed-pump-vert-discharge-pump/

 

[Terry D]

At 130 ft and 24 amps using # 10 wire. I came up with at 6.5% voltage drop.

2x12.9x130x24 / 10380 ( CM of #10 ) = 7.75 volts 7.75 / 120 = 6.5%

So I see what you are saying. Reducing down to a # 10 is alright will just need a j-box to do it

Looks like that pump is just 120 volt

 

[alfredeneuman]

Or would running liquidtite and the THWN wire from the circuit panel to the pump outlet be a better option?

Use regular PVC conduit instead of liquidtite. LT conduit, especially Nonmetallic, is pain to get wire through.
PVC is much less $ as well
EDIT: You can't just tap the receptacle off of the circuit conductors, in part because the breaker will have to be too big.
You need to run separate wires to the outlet, which can be in the same conduit as the ones for the motor

 

[bob15]

Use regular PVC conduit instead of liquidtite. LT conduit, especially Nonmetallic, is pain to get wire through.
PVC is much less $ as well
EDIT: You can't just tap the receptacle off of the circuit conductors, in part because the breaker will have to be too big.
You need to run separate wires to the outlet, which can be in the same conduit as the ones for the motor

I wasn't planning on tapping off the pump wires for another outlet. I understand that needs to be on a completely separate circuit.

I was referring to the outlet for the pump motor itself and 6 gauge wire.

 

[cchamelin]

1 hp = 754 watts, so 2 hp = 1508 watts. At 110v, 1508 watts requires ~ 14 amps (watts / volts = current). At twice the voltage (220v) it would require half the amperage or about 7 amps. This is, of course, full steady state power, not peak starting current, so 24 amps on startup seems reasonable. Also note that as the length of your wire run increases, it causes a voltage drop/loss and thus current draw to start and run the pump will go up a bit more. Your cable choice and breaker would need to accommodate the startup current or you’ll trip the breaker on startup.


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[alfredeneuman]

1 hp = 754 watts, so 2 hp = 1508 watts. At 110v, 1508 watts requires ~ 14 amps (watts / volts = current). At twice the voltage (220v) it would require half the amperage or about 7 amps.


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754 watts is a DC measurement with no losses. No motor is 100% efficient.
110 or 220VAC is not an available voltage in the US (the closest country is Cuba).
Your computations are way off.
Motors are computed by an NEC table (430.28).

 

[Terry D]

1 hp = 754 watts, so 2 hp = 1508 watts. At 110v, 1508 watts requires ~ 14 amps (watts / volts = current). At twice the voltage (220v) it would require half the amperage or about 7 amps. This is, of course, full steady state power, not peak starting current, so 24 amps on startup seems reasonable. Also note that as the length of your wire run increases, it causes a voltage drop/loss and thus current draw to start and run the pump will go up a bit more. Your cable choice and breaker would need to accommodate the startup current or you’ll trip the breaker on startup.


Sent from my iPad using The Garage Journal mobile app

24amps is the full load current, not start up current. It is also the amperage you use in calculating the wire size. As alfred has said, this current is obtained from table 430.248 of the NEC. Start up current or lock rotor current can be be around 5 to 6 times the running current. The motor is at a direct short untill it starts to move. This only happens for a milli second. That is why you are allowed to over size a breaker up to 250% of the FLC for a motor circuit to prevent nuisance tripping.

 

[Showkey]

Or you guys could use 115v and stop nit picking

 

[alfredeneuman]

Or you guys could use 115v and stop nit picking

....and avoid the consensus between all Electrical Engineers, the NEC, CEC, and the International Building Codes?

 

[Showkey]

Consensus that’s funny............there’s is none when half the labels on new products are shown as 115v
Maybe a consensus on GJ a would be possible if a few would stop busting other chops.


Even ran into 130v label this morning...........

 

[bob15]

....and avoid the consensus between all Electrical Engineers, the NEC, CEC, and the International Building Codes?

The website showing the pump my brother bought, lists it at 115v

Then there always this:

 

[alfredeneuman]

The only things that are labeled as 115V are motors and welders, which are made for a 120V system, as are 230V, which are made for a 240V system.
460V motors are made for a 480V system, and 575V for a 600V system.
That doesn't mean that the voltages are described in that way.
A consensus of GJ users is doesn't mean anything when it's wrong.
Calcs are set up for consistency.

 

[Bert_]

1 hp = 754 watts, so 2 hp = 1508 watts. At 110v, 1508 watts requires ~ 14 amps (watts / volts = current). At twice the voltage (220v) it would require half the amperage or about 7 amps. This is, of course, full steady state power, not peak starting current, so 24 amps on startup seems reasonable. Also note that as the length of your wire run increases, it causes a voltage drop/loss and thus current draw to start and run the pump will go up a bit more. Your cable choice and breaker would need to accommodate the startup current or you’ll trip the breaker on startup.


Sent

Kind of forgetting that motors the size are probably only 85% efficient. And what about power factor? Kind of left that part out too.

Fact is a real two horse motor is going to be right around 24 amps at full load. If you want to talk about startup amps it's probably going to be around 100A

 

[bob15]

NEC says that the 2h motor is 24 amps @ 115vac

 

[alfredeneuman]

NEC says that the 2h motor is 24 amps @ 115vac

A good motor calculator is this 1 from Schneider/SquareD
https://www.se.com/us/en/download/document/2014+NEMA+Motor+Data+Calculator/

 

[Hot shot]

My 1 1/2 pool pump motor is 115 volts at 15 amps
It’s on a 20 amp circuit. No startup problems yet in 8 years I thought about a 2 speed motor when I replaced the motor/pump 2 years ago
But I went with the 1 speed instead