Hot tub circuit

[ultramegabob]

Many hot tub manufactures instructions specify a 50 amp circuit with #6 copper wire, at what point would you say that is required? Is there any reason why you shouldn't run #6 SER aluminum to a disconnect with a gfci breaker in it and change over at that point?

 

[Dennis Alwon]

Many hot tub manufactures instructions specify a 50 amp circuit with #6 copper wire, at what point would you say that is required? Is there any reason why you shouldn't run #6 SER aluminum to a disconnect with a gfci breaker in it and change over at that point?

IMO, the instruction mean copper all the way but I am not certain. Also #6 ser is only good for 40 amps not 50 amps. in the 2008 code.

 

[ultramegabob]

IMO, the instruction mean copper all the way but I am not certain. Also #6 ser is only good for 40 amps not 50 amps. in the 2008 code.

Thanks for catching the wire size, I didn't look in the book, I just googled SER ampacity and found a chart, it must have been from an older NEC. what I was mainly wondering is, what is the difference between feeding a disconnect with aluminum versus a sub panel inside the house and then feeding the disconnect with copper? as long as everything is sized properly what difference would it make? the only advantage I can see to copper in a hot tub would be for corrosion resistance.

 

[Dennis Alwon]

Thanks for catching the wire size, I didn't look in the book, I just googled SER ampacity and found a chart, it must have been from an older NEC. what I was mainly wondering is, what is the difference between feeding a disconnect with aluminum versus a sub panel inside the house and then feeding the disconnect with copper? as long as everything is sized properly what difference would it make? the only advantage I can see to copper in a hot tub would be for corrosion resistance.

Many a/c units are this way also adn I know you can install aluminum to the disco and copper to the unit. Being a hot tub I was not certain since pools must be copper the entire way. I would not use aluminum in this case.

 

[Dennis Alwon]

If you look at 680.21 Motors it says the branch circuit must have a copper insulated equipment grounding conductor. However in 680.25 Feeders I see that the egc shall be insulated however if installed within a building we may use any wiring method of Chapter 3. Now article 680.42(C) it does require a copper conductor. So no you cannot use aluminum as the feeder.

 

[ultramegabob]

If you look at 680.21 Motors it says the branch circuit must have a copper insulated equipment grounding conductor. However in 680.25 Feeders I see that the egc shall be insulated however if installed within a building we may use any wiring method of Chapter 3. Now article 680.42(C) it does require a copper conductor. So no you cannot use aluminum as the feeder.

Dennis~ so can you feed a hot tub from a sub panel that is fed with aluminum conductors? what about a service that has a main disconnect outside that uses aluminum conductors?

 

[Dennis Alwon]

Dennis~ so can you feed a hot tub from a sub panel that is fed with aluminum conductors? what about a service that has a main disconnect outside that uses aluminum conductors?

Of course, the existing panels are fine with aluminum. If you read 680.25 the first sentence states:

680.25 Feeders.
These provisions shall apply to any feeder on the supply side of panelboards supplying branch circuits for pool equipment covered in Part II of this article and on the load side of the service equipment or the source of a separately derived system.

Section 680.25(A) tells us the wiring method with an exception for an existing remote panelboard (sub panel) fed from the sevice panel.

Nothing in this section sates I cannot use aluminum for the panel.....I am confused because I always thought a new panel had to have copper conductors. I need to look further. I think this may have changed or I am missing something.

It doesn't matter in your case, because section 68042(C) makes it clear that the feeder must be copper or at least the EGC.

 

[ultramegabob]

Thanks for your replies, I didn't have a codebook handy today, but when I get it back, I will do some more reading, and thanks again!