Need help with electrical design.

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
Hello
I could use some expertise to help me choose the best way to wire my equipment.
I have a 24' AGP with pump and filter located on a back corner of my yard.
Originally I was planning to run 12 AWG THWN wire in PVC conduit 18 inches bellow the ground with twist lock receptacle connected to GFCI circuit breaker.
However, I decided to complicate things and finally pulled the trigger on RJ-45 SWG.
My pump draws 15 Amps on High speed and 4.4 Amps on low and requires 115 Volts.
RJ-45 supposed to draw between 2.5 to 7.8 Amps and can be on 120 V or 240 V circuit.
Is there any advantage to have SWG wired on 240 V circuit?
If not, I supposed to I can still have it hardwired to one circuit with something like 40 Amps GFCI circuit breaker, correct?
This option would be the easiest to achieve but most inconvenient as I would rather remove pump for winter storage.
The most convenient option would be to wire something like 100 Amps sub panel but I'm not sure if this would be worth money and effort for AGP.
I was also entertaining the idea of wiring 2 separate circuits in the same PVC conduit but I'm not sure if there would be much of advantage from it.
Ultimately I want pump and SWG on the same timer. I don't plan to add heater and I don't really need any extra outlets as I run my pool robot off of exterior GFCI outlet on a side of my house.
I run my pump on low speed except for when vacuuming, which thanks to my new robot, I hope I will never have to do again.
What would be the best solution? What would you do in my place?
 

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
Thank you Allen.
I read Mike Holt article you linked on someone else thread while doing my research.
According to it, I would also need to install maintenance disconnect if I want to be up to code, correct?
I'm also a bit confused if convenience receptacle must be also installed.
If I go with two circuits, I can have one terminated with twist plug for a pump as originally planned and the the other with duplex receptacle?
I know that at least some Intermatic timers can control 2 independent circuits but not sure if T104 can.
For example, I see ET1725C can control 2 circuits and is rated at 30 Amps but I don't know if that's 30 on each circuit or 30 combined.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,446
Northern NJ
I need to check but I think the twist lock cord will count as the maintenance disconnect.

Do you want the timers to control the outlets? Why not directly wire the pump and SWG to the timers? The switch in the timer will be the maintenance disconnect.

You can then also have a duplex outlet connected to the hot side of the SWG timer.
 

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
I need to check but I think the twist lock cord will count as the maintenance disconnect.
No need to check on that, you made great point - timer override switch could be used to switch power off as needed therefor negating the need for separate switch.
Do you want the timers to control the outlets? Why not directly wire the pump and SWG to the timers? The switch in the timer will be the maintenance disconnect.
No, I don't want to timer to control outlets. I don't have a problem wiring SWG directly to timer but I would like to have pump plug in to outlet to facilitate removal at closing.
I should be able to wire single pump outlet to be controled by timer and have SWG hardwired to timer. I'm not sure though, if both devices can be connected to the same timer.
Will Intermatic T104R let me do that? If not I thought about hooking SWG to current sensing relay as a workaround. I don't want to have 2 devices on 2 different timers to minimize the risks.
You can then also have a duplex outlet connected to the hot side of the SWG timer.
Another great idea. Quick question though. If SWG draws less than 10 Amps, can I add 20 Amps duplex outlet and have circuit protected by 30 Amps GFCI CB?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,446
Northern NJ
Is your pump going to be 120V or 240V?

The T103 timer has a 120V clock and can switch two 120V hot wires. The T104 has a 240V clock.

Are you really going to plug in more then 10 amps of stuff to the outlet? I would just do a 20A breaker to the SWG timer to the outlet. If you do a 30A breaker you have to use all #10 wire in the circuit.
 

mgarf33

Well-known member
Oct 27, 2013
176
Are you sure you’re reading the current correctly on the salt cell? Typically the cell input is 120/240v, but the output is 24v. So, at 7.8A 24v output, that’s only ~1.56A 120vac Input.
With both pump and salt cell @125% you’re still below the rated 25A/120vac of the 12AWG THWN, so long as you have all connection lugs rated at 75°C.
 
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,446
Northern NJ
So, at 7.8A 24v output, that’s only ~1.56A 120vac Input.
With both pump and salt cell @125% you’re still below the rated 25A/120vac of the 12AWG THWN, so long as you have all connection lugs rated at 75°C.
Good catch on the SWG. I was more focused on the wiring design questions.

Limiting factor for a circuit is the CB shall only be loaded at 80% of its rating. That is 16 amps of load on a 20 amp CB.
 

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
Thank you both. Yes, my pump is 120 V, so if T103 can switch 2 hot wires, that’s perfect. Also good point on SWG load requirements. I couldn’t find that info on a manufacturer specifications, so while browsing thru manual I found given values but I didn’t realize it’s not at 120 V.
 

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
I decided to move away from UF-B cable. General consensus seems, that although allowed, they are really hard to fish thru conduits.
I also found that many THHN labeled cables sold at big home improvement stores are in fact THHN & THWN rated. Looks like this is what I will use.
Since they are individual cables, can I run 2 hot, 1 neutral and 1 ground in underground pvc conduit for my 2 x 20 Amps circuits, or do I need to run 2 of each?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
20,446
Northern NJ
I decided to move away from UF-B cable. General consensus seems, that although allowed, they are really hard to fish thru conduits.
I also found that many THHN labeled cables sold at big home improvement stores are in fact THHN & THWN rated. Looks like this is what I will use.
Since they are individual cables, can I run 2 hot, 1 neutral and 1 ground in underground pvc conduit for my 2 x 20 Amps circuits, or do I need to run 2 of each?
With GFCI CB's you can't share neutrals and need a dedicated neutral for each circuit.

Best to run a complete circuit of two hot blacks, neutral whites, and ground green wires. Six #12 wires.
 

mgarf33

Well-known member
Oct 27, 2013
176
Whoa, I’m confused??? Why are you running separate branch circuits and not 1 feeder to a 2- circuit fused/breaker disconnect? Seems like a waste of material. Not to mention conduit has a fill rating for conductors. You’ll have to run larger conduit. Keep in mind, neutrals are considered current carrying conductors as well.
I think you need to call an electrician, DIY electrical work is not a good idea.
 
Last edited: