110V 20A Spa Hookup Questions

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  #1  
Old 05-28-06, 05:29 AM
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110V 20A Spa Hookup Questions

I was wondering if I could some feedback on the following scenario to insure that I am doing everything correctly and safely.

1) The house we recently purchased has an exterior 110V 20A dedicated circuit and is on a GFCI at the main breaker box. The circuit (originally for a pool pump) runs underground approximately 75' - 100' in conduit to a plug. The hot/neutral/ground are 12 AWG wire and all are sheathed.

2) I purchased a used 110V 20A spa that I have placed next to outlet where the pool pump was plugged into.

3) I purchased a switch and a water proof switch cover to replace the plug outlet and and an 8'ft copper ground rod clamp.

4) I would like to hardwire the spa electrical (hot/neutral/ground) to the switch (interior light switch) which will be then be covered by the weatherproof toggle cover. I have read that the spa needs to be hard wired and also must have a disconnect/shutoff at the spa.

5) I would like to drive the ground rod next to the spa and run a ground wire from the ground at the switch to this ground rod.
The spa will then be grounded via this ground rod and the grounding sources at the main panel.

Any feedback from folks with experience in this area would be greatly appreciated!
 
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  #2  
Old 05-28-06, 11:37 AM
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Return the ground rod. Using it wiould be incorrect.
 
  #3  
Old 05-28-06, 12:04 PM
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Read article 680 of the national electrical code. There are many details to spa installations. Electricity and water do not mix, and getting this wrong can be fatal.

There are specific distance requirements, specific requirements for the type of wire used and type of conduit used.

The ground rod is probably acceptable as a supplemental ground rod, and may be required by the manufacturers installation instructions. It _cannot_ serve as a substitute for a proper equipment grounding conductor back to your main panel, but it sounds like you already have that.

Are the supply wires separate insulated hot/ground/neutral in conduit, or is this a cable (eg. Romex) in conduit?

-Jon
 
  #4  
Old 05-29-06, 07:02 PM
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120v 20a Spa Hookup

Thanks for the advice - do you know if I can access article 680 of the NEC online?

The hot/neutral/ground wires are individually sheathed.
 
  #5  
Old 05-29-06, 07:08 PM
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Received your advice but have a question.

Originally Posted by racraft
Return the ground rod. Using it wiould be incorrect.
I read your advice to not use the ground rod. If you have a minute could you briefly (if possible) explain why using a grounding rod at the spa would be a mistake. I'd like to understand why it is preferable to utilize the ground at the main panel.

Other than nixing the ground rod do you see any problems with my
plan? Thanks
 
  #6  
Old 05-29-06, 09:34 PM
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I disagree slightly with racraft, but I think that I can answer your question.

It is a common myth that electricity tries to flow 'to ground', and that a ground rod will 'drain away' electricity and protect from shock. This is _false_.

Electricity always tries to find a return path to its source. This return path may include the ground, but it is the path to the source that is critical. The thing that is commonly called a 'ground wire' should really be called an 'equipment bonding and grounding conductor', because it provides an electrically continuous path back to the source, held at ground potential by the ground rods at the service. It is this _combination_ of a highly conductive metal path back to the electrical source _and_ a connection to earth that provides the function of the 'ground wire'.

If you use a 'local' ground rod and _don't_ use a proper equipment grounding conductor (ground wire back to your panel), then you will not provide the necessary safety of a solid return path. A 'local' ground rod alone is much more dangerous than a proper equipment grounding conductor back to the source.

Where I disagree with racraft is that in my opinion you can keep the ground rod as a supplement to the equipment grounding conductor. Furthermore this 'supplementary' ground rod may be required by the spa manufacturer. But it can only be used _in addition to_ a proper equipment grounding conductor.

-Jon
 
  #7  
Old 05-30-06, 04:57 AM
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NFPA online access agreement for the 2005 NEC:

http://www.nfpa.org/freecodes/free_a...ookie%5Ftest=1

You may need to load twice.

-Jon
 
  #8  
Old 05-30-06, 05:25 AM
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Let me clarify. Clearly if the manufacturer calls for a ground rod and/or if local rules require one, then one should be installed, according to those instructions.

What I am saying is that you don't just add a ground rod because your friend says you need one, or because you think it will help, or because the guy at the big box store says you need one, or because you didn't run the correct wire and you want to make up for that.
 
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