# Determining Circuit Amperage

2273 Views 19 Replies 9 Participants Last post by  DBB1959
When our pool was installed, the pool builder added two 30A breakers in tandem in the main panel, for powering the 240V pool equipment at the pad.

Also at the pad is the pool control center, as well as a double gang in-use box containing a switch that cuts power for servicing the equipment, and a standard 15A two outlet receptacle to use for whatever.

I want to add a receptacle inside the control box to provide power for a small network module. The 120V tap in the control panel box is clearly marked, and I've verified this with a meter.

Given the two 30A breakers in the main panel, wouldn't each 120V leg of that 240V circuit effectively be 30A, and if so, why would they use a 15A outlet in the in-use box? My first knee-jerk thought was that the tandem 30A breakers effectively divide to provide 15A per leg (sort of like resistors in parallel), but I'm guessing this is not the case...

I don't want to wire in an outlet that's not rated properly, but to me, it's not adding up.
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Is this AC or DC?
Is this AC or DC?
Regular 60Hz AC house wiring...
Regular 60Hz AC house wiring...
In the original post, you said it was pool wiring, now you're saying it's house wiring... I'm confused:vs_worry:
In the original post, you said it was pool wiring, now you're saying it's house wiring... I'm confused:vs_worry:
Perhaps I should have said 60Hz AC residential wiring...

It all comes from the main service panel in the garage, which feeds everything electrical in the home, including inside outlets and lights, and all outdoor lights, and pool equipment. Didn't mean to confuse you.
if the cb says 30a, then it is rated at 30 amps and the wires connected should be 10 ga minimum.

are the trip levers mechanically linked on the circuit breaker?

can you hardwire the network module to the 120v tap in the control box?
Doesn't the pool panel have 15 or 20a circuit breakers in it?
Can a garage panel be a pool panel too?
If the 30A breakers for the pool are 240V, how are you getting 120V? Did they also run a neutral out there?
Can a garage panel be a pool panel too?
A garage panel could feed pool equipment, but it would not be a pool panel if there were any circuits in it that did not relate to the pool.

When the pool equipment requires multiple circuits, it is cheaper to run a feeder circuit to a pool panel and split off the required circuits at that point.

Having the pool panel near the equipment also eliminates the multiple disconnects that would be required if you ran individual circuits from a panel that is out of sight from the equipment.

Pools, spas and fountains have different requirements than most residential wiring. NEC 680.
Doesn't the pool panel have 15 or 20a circuit breakers in it?
No pool sub panel; I had space in my main breaker panel, so that's where the pool breakers they installed (two 30A breakers) were added and wired from/to.

The only thing located at the pool equipment pad is the Pentair control box, and the two gang in-use junction box housing the switch and outlet i mentioned.
A garage panel could feed pool equipment, but it would not be a pool panel if there were any circuits in it that did not relate to the pool.

When the pool equipment requires multiple circuits, it is cheaper to run a feeder circuit to a pool panel and split off the required circuits at that point.

Having the pool panel near the equipment also eliminates the multiple disconnects that would be required if you ran individual circuits from a panel that is out of sight from the equipment.

Pools, spas and fountains have different requirements than most residential wiring. NEC 680.
Okay, so I guess maybe I wasn't clear. I do not have a pool panel, or a separate sub panel that feeds the pool... Here's a breakdown, by location:

- In the garage is my main breaker box that serves the entire residence. The pool builder used the available space in the main breaker panel and added two, 30A breakers with their toggles linked together to feed the pool. They did not install a separate breaker box or sub-panel.

- At the pool equipment pad, they installed the Pentair pool control panel, which contains the relays and low voltage circuitry that controls filter pumps, lights, heater, etc. This Pentair control panel consists of a high and low voltage side. The high voltage side has both 240V and 120V feeds that drive the relays, and step-down transformers for the low voltage circuitry (it was here that I was going to add my outlet, and where my original question originates: is it 15A, 20A, or 30A?).

"Control panel" may have been where I confused folks into thinking it was the electrical "pool panel..?"

- Also at the equipment pad and tied into the Pentair pool control panel is a two gang in-use junction box, that contains a switch that cuts power to the pad location. It also contains a standard, two receptacle 15A outlet.
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if the cb says 30a, then it is rated at 30 amps and the wires connected should be 10 ga minimum.
Looks like it's all 12ga wiring in the Pentair pool control panel.

are the trip levers mechanically linked on the circuit breaker?
Yes. What do you call those? I refer to them as either "ganged," or "tandem," but they are two, individual 30A breakers with the clip that mechanically ties their toggles together. Again, these reside in the breaker panel that serves my entire home.

can you hardwire the network module to the 120v tap in the control box?
Yes. Both 240V and 120V taps are clearly marked, and read as such when I tested them with my meter. My concern is what amp rating I should use for the outlet that I connect up?. The module I want to install just has two prongs, just as if you were plugging in a nightlight, for example - I will need to wire in an actual outlet to accommodate it.
If the 30A breakers for the pool are 240V, how are you getting 120V? Did they also run a neutral out there?
Yes, there is a bus bar in the Pentair pool control panel that serves as neutral. The high voltage side of this Pentair pool control has the 120V and 240V points clearly identified, which I have verified with my meter.

I just don't know what the amp rating is for that circuit. I'm guessing 30A, given the breaker configuration back in the main panel. But why would they have used a regular 15A outlet in the two-gang in-use junction box at the pool pad location? Everything out there is on those "tandem" 30A breakers back at the main panel in the garage.
It sounds to me like, if you have a typical 1-2 hp pool pump, a light, and a convenience receptacle that the 2-pole 30 is oversized and should probably be a 2 pole 20 at most. Since you pool control panel doesn't house any overcurrent protection devices it's possible your convenience receptacle is indeed wired to a 30a circuit which is a code violation. In addition, your pool light shouldn't be on a 30a circuit either, and ost likely your pump/filter is overfused as well.
Take a picture of the pool panel and post it. Nobody can give you accurate information unless we can see what you're talking about.

Or hire a professional. It's a pool, it has water and electricity. Don't put you and your family in danger.
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Take a picture of the pool panel and post it. Nobody can give you accurate information unless we can see what you're talking about.

Or hire a professional. It's a pool, it has water and electricity. Don't put you and your family in danger.
Here's a shot at the equipment pad. In-use box on the left (with cutoff switch and 15A convenience outlet), and the pool control panel on the right:

Same view, but with the pool control panel's door open. The DIN rail and 120V/240V power taps are located behind the blank panel on the right (and where I want to add an outlet and my network module). Low voltage section is on the left:

Here's the main breaker panel in the garage. Tandem, 30A breakers on the left for equipment pad power, and a 20A breaker on the right (which feeds a GFCI outlet that in turn runs out to the pool lights and other outlets installed immediately around the pool area. (Contractor couldn't spell "lights," so I hope he knew what he was doing electrically):

So again, I'm only trying to install an outlet where power already exists in the control panel box, to plug my module into. Seems pretty straight-forward. Just trying to determine amp rating for the outlet I need to use...

We put the pool in about 13 years ago, so this arrangement as is has been in use all this time. And it was inspected by the city along the way. Of course, I know inspections probably don't amount to much in reality...
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So, aside from the double pole 30 you also have a single pole 20- that is the circuit you want to tap off of to install your module receptacle.
So, aside from the double pole 30 you also have a single pole 20- that is the circuit you want to tap off of to install your module receptacle.
Exactly.

I wouldn't pull any power off of that pool module. At best, it'd work but you'd void the listing and run afoul of the electrical code, but at worst you could fry something. You don't know how stable those voltages are or if there is any internal overcurrent protection.

On the subject of electrician spelling, I have met a lot of guys who are very good at what they do, but can't spell to save their lives. I have an entire building full of labeled equipment and about 6 panels are labeled "PANLE". :biggrin2: Not to mention "cubical", "lites", etc. Nothing beats the manhole cover I saw a JFK airport labeled "ELETRICAL". Good stuff.
Exactly.

I wouldn't pull any power off of that pool module. At best, it'd work but you'd void the listing and run afoul of the electrical code, but at worst you could fry something. You don't know how stable those voltages are or if there is any internal overcurrent protection.

On the subject of electrician spelling, I have met a lot of guys who are very good at what they do, but can't spell to save their lives. I have an entire building full of labeled equipment and about 6 panels are labeled "PANLE". :biggrin2: Not to mention "cubical", "lites", etc. Nothing beats the manhole cover I saw a JFK airport labeled "ELETRICAL". Good stuff.
I'm not sure where that 20A breaker feeds into, though. It has to be into the pool control box, though, since the lights are controlled. All the power wiring from the power entry block is daisy-chained down, from one relay's power block to the next one on the DIN rail.

I'll have to trace each one down and see if the pool light relay is powered by itself and not part of the daisy chain, which would be the case if it's fed from that 20A breaker, right? Otherwise, they're using the neutral on the bus bar to create the 120V legs from the 240V feed.

So I suppose it's okay to use a 15A-rated receptacle on a 20A circuit, then? All the general house wiring in my main breaker panel is on 20A breakers.

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