Spa Blower Wiring 240V


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Old 02-08-15, 01:12 PM
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Spa Blower Wiring 240V

I have a blower (Zodiac Polaris QT Blower Model 470-2) for my spa installed as part of my in-ground pool system. I disconnected it a while back and have now forgotten how to wire it up. It's a 240V blower, so it should have two 120V input lines going to it. There two 120V input lines are already there. One has a switch on it and used to operate the blower. There is another 120V line that is not switched. Is it ok connect the unswitched 120V input line (and the switched one) to the blower? How is it that switching off the power to just now hot wire shuts of the entire blower?

BayouMike
 
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Old 02-08-15, 01:54 PM
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You do NOT have "two 120 volt lines" going to the blower motor, you have a single 240 volt two-wire circuit going to the motor.

Your house is served by a 240 volt, three-wire circuit. The so-called "neutral" wire is a connection to the middle of the 240 volt transformer winding and this connection is also connected to the earth which is called a "ground" connection. From either of the two 240 volt wires to the neutral is 120 volts but this does NOT mean that the 240 volts is made up of two 120 volt circuits.

While the single pole switch in one of the 240 volt wires does indeed control the motor it is not the code-approved method. Code requires that "all ungrounded lines (any wire not connected to the earth) be opened when securing the operation of the connected device" [my wording, not a direct code quotation] That means that you SHOULD have a two-pole switch connected to BOTH wires. Your single pole switch works because it does interrupt the complete circuit but it is NOT as safe as the two pole switch.
 
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Old 02-10-15, 08:44 AM
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Ahh. That explains it. I appreciate that you described the two 120v lines as you did...it clear things up for me. My pool pumps are wired up the same way and I was getting 120v across each lead to ground event when one breaker was off.

I'll put a two pole switch on the blower as you recommend. When was this put into the code? The pool is 1990 vintage and I'm wondering if it was up to code at that time or not. I'm guessing it was not wired to code originally and that there may be other "problems". I know it's not up to current code since it has no GFCI's in the circuits.

Also, I'm wondering if the circuit breaker for the 240v circuit is right. The pool equipment is on two tandem 120V breakers with one side of each tandem breaker carrying a 120V line. In other words, I have one tandem breaker with the top going to the water softener and the bottom going to one side of the pump, then I have another tandem breaker with the top going to the other side of the pump and the bottom going to lights. Certainly, the toggles for two pump 120v lines aren't connected so they don't both trip at the same time and you can turn one off without turning the other off.

Thanks for your help Furd. Very articulate response!
 
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Old 02-10-15, 08:51 AM
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For inground pools it was a pretty recent addition to the code, somewhere around 2005 or 2008. Above ground pools and spas were quite a bit further back. However a "package spa", doesn't necessarily have to follow the NEC for the internal components, because it is sold as a complete assembly from the manufacturer. The NEC only applies from the building wiring up to the point of connection to the unit.

The tandem breaker is acceptable only if there is a "common trip" mechanism between the poles. These breakers are sometimes called quads, and they come in all permutations of common or individual trip so it requires close investigation. The separate tandem breakers is definitely wrong and unsafe.
 
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Old 02-10-15, 08:55 AM
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Also, I'm wondering if the circuit breaker for the 240v circuit is right. The pool equipment is on two tandem 120V breakers with one side of each tandem breaker carrying a 120V line. In other words, I have one tandem breaker with the top going to the water softener and the bottom going to one side of the pump, then I have another tandem breaker with the top going to the other side of the pump and the bottom going to lights. Certainly, the toggles for two pump 120v lines aren't connected so they don't both trip at the same time and you can turn one off without turning the other off.
It doesn't sound as if any of the wiring was ever inspected because this is definitely wrong. There are quad breakers manufactured that would correct this situation by code, but in my opinion, the preferred method would have been to use a larger subpanel that had room for full sized 2 pole breakers.
 
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Old 02-10-15, 06:02 PM
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It's an inground pool. Living outside the city limits, it's up to the electrician on the job, who may not be qualified. I'll have a real electrician look at it and square me up. Better safe.
 
 

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