A sparky here at work moonlights doing additional small time resi work. He asked me (I don't know why he picked me, I am just an EE) what the code requirements were for the installation of an outdoor hot-tub. I know there have been posts on this topic (disconnect locations, GFCI requirements etc), please could some of you point them out to me with the relevant code sections if you have them handy.

Article 680, which covers pools, has a 'spa and hot tub' section that modifies the pool rules.

It's a good idea that he also check with the local town, as local interpretations - especially regarding whether the ground wire need be insulated - vary. It's possible the town will want an insulated ground wire all the way back to the main panel ... which rules out NMC as a wiring method.

If there's a gazebo over the thing, a ground rod, in addition to the ground wire, is also a good idea. Again, this is a matter of some discussion.

Wires need to be buried deep - preferably 2 ft down. Getting into design issues, I prefer pipe. These steps protect against the gardener damaging them when working on the lawn sprinklers.

Finally, there is the matter of disconnect location. Putting it in the enclosed area that also hides the air conditioner is a common error. An "emergency stop" is not required for residential tubs.

680.21(A) pretty much puts you in conduit. You also need GFCI protection. The typical spa setup is a 50a branch circuit with a GFCI breaker and a disconnect box where the spa wires in. Some packaged spas also include a built in disconnect or even GFCI protection so it is good to know what you have before you start. I am not sure how you bond a preexisting concrete deck but by my reading it is still required. You also need to bond all metal within 5' with #8 solid (window frames, screen enclosures, rails, fences and ladders). Most AHJs also want tempered glass in windows near the tub.

Thank you, Greg, for highlighting some common variations.

I've seen countless variations ... as well as quite a bit of variety in the tubs themselves. The last one I did came with its' own "slab," made of something resembling styrofoam, but looking like cement!

All more reasons to have a chat with the AHJ before work starts ....

I suppose that slab is the way around 680.26(C) (3' paved surface bonding.)
Prior to 2005 the bonding of the deck under a spa was not really looked at. I know I did mine way back in 1976 but I was the one who was going to be using it

Probably made from AAC - autoclaved airated concrete. It is getting more prevalant in building and building materials. Its lightweight and yet fairly sturdy.

Greg,

Someone mentioned disconnects, and emergency disconnect is not required for resi spas, but a disconnect for the motors is still required to be within 50 feet and within eyesight of the motors, if it is not part of the spa package. As for bonding concrete on existing patios around here some EC's are installing rubber mats around the tubs or wooden decks, this way you are insulated from the concrete.

I suppose all these rubber mats and plastic decks are fine ... until they get wet.

The only way to eliminate voltage gradients is with bonding.
That is why we have 680.26 in the first place

Mike is that like the Ytong concrete? In any case I would still like to see them put a copper grid in it and a bonding lug.

Greg- I wonder if a grid is even required around an out door spa if it is above ground. I assume this is the type of spa we are talking about. Maybe it could be a code proposal for the 2011 code? Or maybe an exception?? 680.42 and reference to B kinda tells us what to do with bonding an outdoor spa.

If you can call the deck a "paved surface" I think it needs to be bonded. If this is a wood/Trex deck, no.