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I'm installing a Aquarite chlorinator, and something went terribly wrong!

As instructed by the manual for 110V installations, I removed the jumpers from terminals 2/3 and moved them to terminals 1/2 and 3/4. This is connected to the Load side of my 110V timer. The load side is also connected to the pool pump. I also ensured that the bonding wire on the bottom of the cabinet was connected to the bonding terminal on the back of the pump.

But when I flipper the timer manual switch to ON, I immediately got a loud BANG from the Aquarite cabinet, and it flipped the 60A breaker dedicated to the pump/timer/chlorinator as well as the 60A breaker behind it in the main panel.

The timer and pump appear unscathed by the ordeal, but the main circuit board of the Aquarite shows significant damage to at least the two red MOVs on either side of the terminal block (you can see the pieces and smoke in the photo below).

So, what did I do wrong? As far as I know, the circuit is 110V, not 220, and the instructions explicitly told me to connect the controller to the load side of the timer so it would not be running while the pump is off.

In the photo below, I wired red to hot (timer load), and black to neutral (unswitched). The corresponding wires in the breaker box are black and white, respectively.

UPDATE: Idiot electrician did not label the breaker as 220V. Idiot me assumed it was 110V. So that was the problem. Just confirmed with voltmeter.

Shot of electrical connections.

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1 Answer 1

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You've already sorted this out, but the lesson here is simple: Don't ever assume anything.

Determining 220 vs 110 at the panel is fairly simple. You have a phase A and B in your house, which come from each side of the transformer. The transformer is center-tapped to ground, and this is your neutral wire.

"Voltage" is really just a measurement of potential difference between two points, and so if you think of it that way, the voltage between A and B is 220V, and the difference between A and neutral or B and neutral is 110V.

In your breaker panel, every other row of breakers is a different phase.

enter image description here

To get 110V power, you need a neutral wire, and a hot wire from either phase A or B (it doesn't matter which). So any single breaker, like #3, is only supplying 110V power.

To get 220V, you need one hot on phase A, and one on phase B, like the 220V breaker at the bottom right (#4/#5).

This picture also includes some tandem breakers (the one currently being installed is a tandem), in which case both circuits are on the same phase. That is, both #1 and #2 are on phase A. If you measure the voltage (potential difference) between #1 and #2, you'll get 0V.

Voltage between #1 and #4 is 0V, and between #3 and #5 is also 0V.

Voltage between #3 and #4 is 220V, since they're on different phases.

Note though, it's against code to use single circuit breakers to run a 220V circuit, since if the power trips, you want all the power to trip, not just one side (since that would leave 110V hot).


The other huge tip-off at the circuit is the wire colors (though again, never assume, always test). There aren't a ton of requirements for wire colors, other than two: white means neutral, green (or bare) means ground. If you use a white wire for something other than neutral (common in a light switch, for example), it must be indicated on both sides, usually by wrapping a piece of red or black tape around it. Black is hot.

The next most common color is red, which has two very typical meanings: * switched, which you'll commonly see in duplex receptacles where one is constant, and one is controlled by a switch * hot for 220V, which is the case here, where red is the opposite phase from black, to provide 220V.


To sum up:

  • In the panel, a double-sized breaker on the circuit means 220V
  • At the branch, not having a white neutral wire means you can't get 110V.
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All good points, Greg. In my case, the breaker for the pool pump is in a stand-alone box (it acted as a switch before I installed the timer). It then runs through a hornet's nest in another distribution box before ending somewhere in the panel. The breaker's manufacture label had "110/220" on it, and the wires were black and white (no marks or extra labels on the white side, looked like a plain ol' neutral). My bad for not verifying with a voltmeter. –  richardtallent Mar 27 '11 at 20:16

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