Efficiency of 120 Hot tub vs 208/240

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wireman71

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I bought a hot tub that is configured for both voltages so I'm deciding which one to wire for. Would a 120 volt circuit use anymore wattage than a 208/240 circuit? I'm thinking no. If this is true then is 277 volt lighting any more efficient that 120 volt or can you just put more lights on a circuit? Next my manual mentions GFCI protection if you go the 208/240 volt route but doesn't mention it for the 120 volt setup. I personaly don't see a issue with not having a GFCI for my personal hot tub as I don't see the potential for shock with a functioning ground connected. And my code book is 2002. Only requirements I see are a disconnect within site(residential) and a service recept 5-10 feet away for service.
 
wireman71 said:
Next my manual mentions GFCI protection if you go the 208/240 volt route but doesn't mention it for the 120 volt setup. I personaly don't see a issue with not having a GFCI for my personal hot tub as I don't see the potential for shock with a functioning ground connected. And my code book is 2002. Only requirements I see are a disconnect within site(residential) and a service recept 5-10 feet away for service.
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If I'm getting in it, it gonna have GFCI protection.

I find it hard to believe that it doesn't mention GFCI protection at 120v.
 
wireman71 said:
I bought a hot tub that is configured for both voltages so I'm deciding which one to wire for. Would a 120 volt circuit use anymore wattage than a 208/240 circuit? I'm thinking no. If this is true then is 277 volt lighting any more efficient that 120 volt or can you just put more lights on a circuit? Next my manual mentions GFCI protection if you go the 208/240 volt route but doesn't mention it for the 120 volt setup. I personaly don't see a issue with not having a GFCI for my personal hot tub as I don't see the potential for shock with a functioning ground connected. And my code book is 2002. Only requirements I see are a disconnect within site(residential) and a service recept 5-10 feet away for service.
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If you choose NOT to use the 240/120 voltage, you will probably not be able to use both the jets and heater at the same time, OR it will just take longer to heat up, Every hot tub I ever wired included a cut sheet on the issues with using 120 vs 120/240.

You would not see me wiring a Hot Tub without GFI protection...
 
Wouldn't the ground path protect you as it is likely to be a much lower resistance path than you stepping out of your tub? My manual doesn't mention those downfalls. And the dealer is poor at best. Bought it new from a guy that won it. Big discount.
 
Thinking of going with the 208/240 option, been checking google and it sounds like the 120 volt models can lose heat in the winter so don't want that. So it looks like my questions are moot as the manufacture does require GFCI protection on the higher voltage. Probably a good idea anyways.
 
wireman71 said:
Thinking of going with the 208/240 option, been checking google and it sounds like the 120 volt models can lose heat in the winter so don't want that. So it looks like my questions are moot as the manufacture does require GFCI protection on the higher voltage. Probably a good idea anyways.
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I just read the owners manual, if you wired it with 120 only it draws 20 amps, and at 120/240 volts it draws 40 amps, so the heater is definitely cut in half...
 
So do you think there is a real shock hazard if a GFCI isn't used? I wouldn't circumvent the NEC but the manufacture specs on my own personal gear.. I'm poor, lol.
 
wireman71 said:
So do you think there is a real shock hazard if a GFCI isn't used? I wouldn't circumvent the NEC but the manufacture specs on my own personal gear.. I'm poor, lol.
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You just bought a hot tub... :grin: and yes I do feel its a shock hazard, I would not risk my life to test this either...
 
stickboy1375 said:
I just read the owners manual, if you wired it with 120 only it draws 20 amps, and at 120/240 volts it draws 40 amps, so the heater is definitely cut in half...
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One-fourth, actually, but who's counting? :smile: A typical 6Kw heater at half voltage, which means also half current, ends up at 1.5Kw.

W = E x I
1/2 x 1/2 = 1/4
 
I'm still on the fence on the GFCI issue.. Does the water normally have conductivity to the ground? I'm leaning towards a GFCI install but want to be convinced that it's worth the extra $$. What's funny is I wouldn't install one for a customer without one as the manual specs it. But like AFCI is it really needed?
 
wireman71 said:
I'm still on the fence on the GFCI issue.. Does the water normally have conductivity to the ground? I'm leaning towards a GFCI install but want to be convinced that it's worth the extra $$. What's funny is I wouldn't install one for a customer without one as the manual specs it. But like AFCI is it really needed?
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This is something I guess you will have to decide on... but I thought you were going with the 240v? IF so then you will need the GFI per manufacture...
 
I'm supposed to per manufacture. But i'm curious about any real hazard involved by just doing a per NEC install.
 
GFCI trips at 5 milliamps.

Under 1 amp is lethal.

Breaker trips at somewhere over 20 amps. (Assuming a 20 amp breaker)

Don't you think it is possible to have a slight ground fault with enough resistance to limit the current to somewhere below 20 amps?

Remember, a human will be immersed in water here. - low skin resistance.

IMHO, the lack of a GFCI requirement in the instructions in a major oversight on the manufacturer's part.
 
A hard-wired Hot Tub, just like a hardwired swimming pool pump, does not require GFCI. The assumption is that the bonding (grounding) of a hardwired unit is more assured than a unit that pugs in. You are correct that proper bonding (grounding) is much safer than GFCI protection. That said, the NEC is a MINIMUM STANDARD; you are allowed to exceed the NEC in providing safety. Knowing what you know about electricity, why would you NOT install GFCI? If the $ that a GFCI breaker will cost you is a problem, perhaps you should rethink the hot tub. Think about the current that you will have to buy to keep that thing going. GFCI is a tiny fraction of the expense, but it is not required and will add little additional safety to a properly bonded (grounded) unit. It is a "belt and suspenders" approach to electrical safety. As professionals we should be setting the example for providing the maximum safety available, there are enough "electricians" that are happy to do the minimum or less....
 
Thanks all and I'm glad you were able to beat some sense into me. It's good to have this stuff down so when a customer asks someday I can tell them why. : )
 
Make sure you follow the manual with regard to which dip switches or other alterations need modification on the circuit board, depending on your voltage/amperage choice.

My hot tub has 2 5-hp motors for 4 of the seats and the footwell, and 2 seats with their own individual 1.5 hp motor and controls, and a small fractional HP motor that runs 24/7 for the ionizer and ozone generator.

Because the instructions weren't clear, and the unit was not setup properly by the factory for my request of 70a 240v, the heater would never operate simultaniously with any pump except the fractional hp. pump. 1st winter the tub started cooling off 1/2 hour into a hottub party during a snowstorm. Had to move the festivities indoors. (Manufacturer set the tub up for a 40a 240v supply.)
 
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