ECN Forum Forums Photo Discussion Forums Photos for General Discussion Hot tub install - Separate Structure?

This thread makes me glad my job consists only of getting 20 cinema projectors ready to run in a cinema where the opening date was bumped up a full month... (even though the building isn't ready yet!)

Call it an appliance.

Call it a hot tub.

Call it a fiberglass bucket to frolic in.

It is still IMO a structure when applying the NEC.

A vehicle is still a vehicle regardless if it is Ford Focus or a Mack truck.

If we determine that there is a feeder running to this hot tub the NEC requires a ground rod.

Sorry I have been busy with other things but I do want to get back to John C's points in this thread.

Bob


[This message has been edited by iwire (edited 10-31-2005).]

I am going to ignore the issue of what is actually required or permitted by code, and make the point that a grounding electrode is IMHO a good idea for safety.

Regardless of any grounding electrode, the feeder/branch circuit going to this appliance/structure will include at least one grounded conductor electrically connected to a grounding electrode.

The hot tub almost certainly will include fittings exposed to the water, quite probably in contact with the water, and bonded to the electrical system ground.

The soil or concrete around this hot tub will almost certainly be wet when the tub is being used.

You have now set up a situation where the tub of water is at the ground potential of the house, by virtue of the equipment grounding conductor, the house grounding electrodes, and the bonding at the tub, while the soil or concrete around the tub is at the local ground potential, with both items wet, and people with very little clothing likely to be in contact with both. IMHO this is a perfect setup for electric shock caused by any sort of earth current (nearby lightning strike, stray voltage caused by improper neutral connection on a neighbor's property, POCO 'single wire earth return' wiring, etc.)

If this were my own property, I would want the UFER or a ground ring, regardless of what the code requires.

Note that this sort of bonding is required for an in-ground pool, including an 'equipotential plane' surrounding the pool.

-Jon

Jon, I am totaly behind you on a equipotential plane being needed for this type installation, and that is what I would do. But I would never install a ground rod here and think that it is now safe, or performance was enhanced because of it.


Dnk...

"If this were my own property, I would want the UFER or a ground ring, regardless of what the code requires."

Me too... Concrete pad, and /or footings bonded to the motor control box in the very least.

Been on too many service calls where people get shocked by touching the water, and standing on the ground barefoot.

GFI's and pump motors fail, heaters burn up over time, landscrapers pick ax the feed. Who knows what else... But at some point something will go wrong, and someone will be standing there half, or fully naked for what ever it is....

Winnie, lest you be concerned...There is a grounding electrode conductor- a ground wire- run to this tub. I am asking about an additional grounding electrode-ground rod into the earth- as well.
The best explanation I have seen about the purpose of ground rods related to lightning protection. This is a completely separate from clearing faults.

The "pick ax" issue was why I used pipe, and buried it DEEP. 24" to top of pipe. I know you might argue that code would allow for less depth, but I am a believer in Murpy's Law.

I guess what I saw inside the tub could be called a "load center." There were separate switches, breakers (or fuses) and connectors for each part of the assembly. It was all part of the control board, though....and not a "load center" as you might get from Square D.

Reno,

The point that I was making was that the EGC could actually be a _source_ of a shock if the _local_ ground potential at the hot tub is different from the _local_ ground potential where the building electrical system grounding electrode is located. I don't see further grounding the electrical system as offering any sort of performance benefit; instead I see this as 'bonding' the earth at the hot tub to the same grounding electrode system as the water in the hot tub.

I was thinking in particular of this thread https://www.electrical-contractor.net/ubb/Forum1/HTML/003127.html where the customer was being shocked between a bonded water spigot and the wet ground nearby. The voltage to ground at the spigots was present even when the main to the house was off. The problem was POCO neutral current going through the earth.

-Jon

I have a hot tub in my basement, is it a structure?? what about seperate??

Was it built or constructed or did it grow from a hot tub seed?

NEC Article 100.


That is the entire definition, I have a hard time believing a hot tub is not a structure per this NEC definition.

Remember the NEC also defines 'Building' and while a building is always a structure a structure is not always a building.




The NEC does not define separate so we must use the common definition. By the common definition your hot tub is not separate from the main structure (your house) as it is inside it.

Here in MA they have modified the definition of structure and it makes it clear a structure is not only shelter.

MA Amendments

Walrus, If I remember correctly you wire service stations?

Many times the pump islands would have to be considered separate structures as the roof above them is not connected to the the main building.

Then of course the pumps at the tanks would be in another structure.

It gets depressing if you think on this to much.

Bob

So what you're saying is my hot tub is structure within a structure??. I see it as an appliance in my basement, similar to a washer or dryer. By the definition in NEC though it appears you are correct.I would call it confusing but really its written right out in plain english