SWG Power Source

[JKB121]

I am converting to SWG in the spring (CircuPool Universal UL40) . The SWG unit can operate on either 120 or 240. It is factory wired for 240 and I'd probably rather keep it that way. (it seems to use less power on 240). That said, I have 2 circuits on the pad. 20 amp/120 for the 2 speed Circulation Pump and 60 amp/240 for the Heat Pump. If I were to pick up power from the 60 amp 240 circuit for the HP, I'm thinking I'd need to install a 60 amp disconnect WITH an optional breaker to supply the SWG. The only ones I can find like that are over 300.00. Picking up the power from the 120 circuit would be much less expensive, but it seems most run them on 220.

Has anyone picked up the power from a dedicated HP circuit?

Thoughts???

 

[proavia]

Wire it to the pump at 120 volts. Is the pump on a timer? If so, wire the SWG so it also works on the timer. The SWG should only receive power when the pump is running. If there is no timer, suggest you install one and wire the pump and SWG to be controlled by the timer. The SWG flow switch is a secondary safety device - a timer is the primary safety device.

 

[JKB121]

The pool does/did not have a timer. I ran it 24/7. When the HP calls for heat, the pump switches to high. Unfortunately, I found that allowing the HP to run at night did very little to heat the pool, but did jack the electric bill up to 300/month. This spring the pool will be running only during the day when the HP will be more efficient. (timer will be added). I was going to use the flow switch as the only means of switching the SWG because the manual did not state otherwise. Thanks for the input!

 

[markayash]

I have the edge and installed a plug on the cord and just use a smart plug. Then if my pump runs from 9am to 9pm I set the smart plug to run from 9.15 to 8:45 to be safe
Here is the one I use, wide open mine never pulls more then 2amps. I also like this smart plug because it shows watts and you can set it to shut off if it goes above 300 watts for example

VeSync Smart Plug by Etekcity, 2 Pack Mini WiFi Outlets, Works with Alexa, Google Home & IFTTT, Remote Control from Anywhere, WiFi Energy Monitoring with Schedule Function, No Hub Required, ETL Listed https://www.amazon.com/dp/B06XSTJST...abc_P01Z57ZQJ26Z0XB1C54Z?_encoding=UTF8&psc=1

 

[ajw22]

(it seems to use less power on 240).

The SWG uses exactly the same power in watts at 240V or 120V.

Running the SWG at 120V will give you more flexibility on timers and how you connect it.

 

[JKB121]

thanks!!!! ...and will save money on installation. Good to know. I appreciate the help on here!

 

[jmastron]

The SWG uses exactly the same power in watts at 240V or 120V.

Running the SWG at 120V will give you more flexibility on timers and how you connect it.

Agree with running at 120V in your case. If you have an external timer for the pump it can make sense to supply it from that, but if not a cheap WiFi plug works well; that's what I did. Some of the Circupool models do indeed say you can energize it continuously with the flow switch alone controlling -- but I agree with others that it's a better idea to have a 2nd control in case the flow switch fails.

I actually leave my Calimar SWCG at 100% all the time, and adjust the start/end time from the WiFi plug's app as needed to increase/decrease production, so it's like a $30 (or whatever the Kasa plug was) automation system Convenient since I bring the water sample inside to test and don't have to go back out again.

To expand on the power comment -- power (in Watts) is voltage (in Volts) times current (in Amps) -- for example 240V @ 2 Amps is equivalent in power to 120V @ 4 Amps; both are 480W, and running for an hour consumes 0.48 kWh (which is what you pay for). Wiring the power supply to 120V just changes which windings are used so the output voltage to the cell is the same.

 

[JKB121]

To expand on the power comment -- power (in Watts) is voltage (in Volts) times current (in Amps) -- for example 240V @ 2 Amps is equivalent in power to 120V @ 4 Amps; both are 480W, and running for an hour consumes 0.48 kWh (which is what you pay for). Wiring the power supply to 120V just changes which windings are used so the output voltage to the cell is the same.

Interesting... I always thought my larger pieces of tools and equipment like compressors ran cheaper on 220..... learned something here again! thanks.

 

[ajw22]

Interesting... I always thought my larger pieces of tools and equipment like compressors ran cheaper on 220..... learned something here again! thanks.

They run better on 220V, not cheaper. Tools can get more power from 220V.

Both 120V and 220V circuits are usually limited to 15 or 20 amps due to wire size.

On a 120V circuit the tool can get 1,800 watts of power if it needs it.

On a 240V circuit the tool can get 3,600 watts of power if it needs it.

Tools with motors often need more power when starting or when put under high loads for a brief period of time.

For a give amount of power (watts or HP) the cost will be the same as long as the electrical service can deliver it.

 

[JKB121]

Agree with running at 120V in your case. If you have an external timer for the pump it can make sense to supply it from that, but if not a cheap WiFi plug works well; that's what I did. Some of the Circupool models do indeed say you can energize it continuously with the flow switch alone controlling -- but I agree with others that it's a better idea to have a 2nd control in case the flow switch fails.

I actually leave my Calimar SWCG at 100% all the time, and adjust the start/end time from the WiFi plug's app as needed to increase/decrease production, so it's like a $30 (or whatever the Kasa plug was) automation system Convenient since I bring the water sample inside to test and don't have to go back out again.

To expand on the power comment -- power (in Watts) is voltage (in Volts) times current (in Amps) -- for example 240V @ 2 Amps is equivalent in power to 120V @ 4 Amps; both are 480W, and running for an hour consumes 0.48 kWh (which is what you pay for). Wiring the power supply to 120V just changes which windings are used so the output voltage to the cell is the same.

I will be using an automation with Samsung SmartThings. It can be included in the system I built to operate the 2 speed pump which is controlled by the Heat Pump. I guess the flow switch will be the "back-up". If the pump and SWG are controlled by the same relay, is there really a need for the flow switch? (assuming that the SWG will operate without it)

 

[ajw22]

. If the pump and SWG are controlled by the same relay, is there really a need for the flow switch? (assuming that the SWG will operate without it)

Yes, you still need the flow switch.

Consider if the pump motor fails. Power will be to the pump and SWG but no water flow. You want the flow switch to shutdown the SWG.

 

[JKB121]

Yes, you still need the flow switch.

Consider if the pump motor fails. Power will be to the pump and SWG but no water flow. You want the flow switch to shutdown the SWG.

Good point... and easy enough to do. Thanks!

 

[markayash]

They run better on 220V, not cheaper. Tools can get more power from 220V.

Both 120V and 220V circuits are usually limited to 15 or 20 amps due to wire size.

On a 120V circuit the tool can get 1,800 watts of power if it needs it.

On a 240V circuit the tool can get 3,600 watts of power if it needs it.

Tools with motors often need more power when starting or when put under high loads for a brief period of time.

For a give amount of power (watts or HP) the cost will be the same as long as the electrical service can deliver it.

Is it true you can use a thinner wire with 240 vs 120 for the same application? I was told that years ago but want sure if it’s true.

 

[Newdude]

For the purpose of this low draw SWG discussion, probably. As a general rule of thumb, 15A circuits can use 14Ga, 20A needs 12Ga and 30A needs 10Ga. But with a long enough circuit, the voltage drop may increase and maths are needed to see if you still need the larger gauge. With the SWG controller being so close to the pool panel, it’s probably fine. Also, only needing a few feet of material, it’s not any kind of savings in the grand scheme of things to use smaller wire here if OP was going the 220V route.

*not an electrician, just have a decent grip on it (that also gets me into trouble sometimes ). Anyone please feel free to correct me.

 

[jmastron]

Is it true you can use a thinner wire with 240 vs 120 for the same application? I was told that years ago but want sure if it’s true.

Yes, because the current flow is half at 240V than it is at 120V for the same wattage, and that's all the wire "cares" about. Higher current requires thicker wires.

That's why "low voltage" uses like undercabinet or landscape often have much thicker wires on the low voltage side, especially for older incandescent/halogen bulbs. Take a pool example -- a 300W 120V light is 2.5 amps, which might need 16 gauge wire (similar to lamp cord). The same wattage 12V bulb needs 25 amps, which needs 10 gauge wire like might be used for your 30 Amp clothes dryer! LED bulbs are especially great for low voltage usages for that reason, since they typically use 1/10th the wattage for similar light and thus reduce the wire gauge needed.

Incidentally, even those of us with electrical engineering backgrounds (I'm a computer engineer, usually dealing with MUCH lower voltages!) mix this up. I miswired an Intermatic pool light transformer because my brain insisted that the fatter wires must be the 120V line side, despite the fact that I should have known better. After pumping 1200V instead of 12V through the bulb and ordering a new one, I forced myself to look at the schematic on the cover more carefully and realized my mistake...

 

[ajw22]

Is it true you can use a thinner wire with 240 vs 120 for the same application? I was told that years ago but want sure if it’s true.

The size wire used is based on the maximum amps, not volts, the wire will carry and the size circuit breaker the wire connects to. The wire size amp capacity must never be less then the circuit breaker rating. CBs are there to protect the wires from excess amps.

 

[markayash]

For the purpose of this low draw SWG discussion, probably. As a general rule of thumb, 15A circuits can use 14Ga, 20A needs 12Ga and 30A needs 10Ga. But with a long enough circuit, the voltage drop may increase and maths are needed to see if you still need the larger gauge. With the SWG controller being so close to the pool panel, it’s probably fine. Also, only needing a few feet of material, it’s not any kind of savings in the grand scheme of things to use smaller wire here if OP was going the 220V route.

*not an electrician, just have a decent grip on it (that also gets me into trouble sometimes ). Anyone please feel free to correct me.

I am lucky, my pump is about 2’ from the panel.

 

[wireform]

Keep the SWCG on the 120 v circuit same difference. Tools and larger appliances also run on 240 as it balances the house loads more equally. If you were to have a back up home generator you'd also want the phases close in load but this SWCG is nothing in the big scheme of things.