EPB for hot tub

sbrehler

Member
Hi all:

I have read through many of the previous posts on this but can't seem to get an answer to my questions...or, enough answers for me to form a picture of how I'm going to do this correctly.

This is going to be my first hot tub connect for a client who is installing an above ground hot tub on a pad that he built. The pad is, from what I have seen/been told, a 6" high box (4'X4' PT) with non-reinforced (no rebar - unknown depth) pilings spaced in it, packed with sand - pavers on top. The pad will be about 1' larger in diameter than the tub.

Here is what I'm proposing based on 2011 NEC/ Sec 680:

Spa is requiring a 120/240V 50A GFCI protected ckt.

- Run #8/4 (if I can get it - a cable w/ an insulated ground) from panel in garage through crawlspace, pop out through sill plate into a disconnect (10' away from spa - within sight). LFMC over to the tub.

- Bury a #8 bare solid CU 6" deep around the tub just on the outside edge of the pad (or within a few inches) - bonding it to the gnd bar in the pump housing (provided there is space/accomodations). Does this need to be a complete ring? That is, connected like a lasso and then run up into the ground bar? If I can't make a bond in the pump housing I guess I'll run it back to the disconnect?

- I have written to the company to see if the hot tub has provisions for bonding the water. If not, what could I do? Connect a coffee can to a wire and drop it in the tub?:thumbsdown: What have you other guys done if there aren't provisions for doing this?

Lastly, provide a service receptacle on a separate ckt. located by disconnect.

Hopefully, I have painted a clear enough picture so that you might see if I'm missing something here. Again, I have read many variations for installations in previous posts (I.E. ring -vs- grid EPB, cable sized at continuous -vs- noncontinuous duty, etc....not much on the bonding of the water.

Thanks for your input...

Scott
 
T

taylorp

Guest
I think you should re-read sections 680.40 through 680.44.

Short answer, it seems that you will need an equipotential plane if this hot tub is outdoors. A ground ring is required to be no less than a #2 awg, but why would you want to install one? Flexible conduit is limited to a maximum of 1.8 m (6ft) outside the tub, so 10 feet of flex is a no-no.

As I read the Code, a hot tub installed outdoors shall comply with the provisions of Parts I and II of article 680 except as permitted in 680.42(A) and (B).
 

augie47

Moderator
Staff member
Location
Tennessee
Normally I would agree, BUT, there is one wrinkle. In this case, 680.42 in the '11 Code has had a TIA published which changes the rules:

Reference: 680.42(B)
TIA 11-1
(SC 11-3-10/TIA Log #1005)
Pursuant to Section 5 of the NFPA Regulations Governing Committee Projects, the National Fire Protection Association has issued
the following Tentative Interim Amendment to NFPA 70?, National Electrical Code?, 2011 edition. The TIA was processed by Panel
17 and the National Electrical Code Technical Correlating Committee, and was issued by the Standards Council on March 1, 2011,
with an effective date of March 21, 2011.
A Tentative Interim Amendment is tentative because it has not been processed through the entire standards-making procedures. It is
interim because it is effective only between editions of the standard. A TIA automatically becomes a proposal of the proponent for the
next edition of the standard; as such, it then is subject to all of the procedures of the standards-making process.
1. Revise 680.42(B) to read as follows:
680.42(B) Bonding. Bonding by metal-to-metal mounting on a common frame or base shall be permitted.
Exception No. 1: The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26.
Exception No. 2: A listed self-contained spa or hot tub that meets all of the following conditions shall not be required to have
equipotential bonding of perimeter surfaces installed as required in 680.26(B)(2):
(1) Is installed in accordance with manufacturer?s instructions on or above grade.
(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top
rim of the spa is greater than 28 inches (71 cm).
Informational Note: For further information regarding the grounding and bonding requirements for self-contained spas and hot
tubs, see ANSI/UL 1563 ? 2009, Standard for Electric Spas, Equipment Assemblies, and Associated Equipment.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
Normally I would agree, BUT, there is one wrinkle. In this case, 680.42 in the '11 Code has had a TIA published which changes the rules:

Reference: 680.42(B)
TIA 11-1
(SC 11-3-10/TIA Log #1005)
Pursuant to Section 5 of the NFPA Regulations Governing Committee Projects, the National Fire Protection Association has issued
the following Tentative Interim Amendment to NFPA 70?, National Electrical Code?, 2011 edition. The TIA was processed by Panel
17 and the National Electrical Code Technical Correlating Committee, and was issued by the Standards Council on March 1, 2011,
with an effective date of March 21, 2011.
A Tentative Interim Amendment is tentative because it has not been processed through the entire standards-making procedures. It is
interim because it is effective only between editions of the standard. A TIA automatically becomes a proposal of the proponent for the
next edition of the standard; as such, it then is subject to all of the procedures of the standards-making process.
1. Revise 680.42(B) to read as follows:
680.42(B) Bonding. Bonding by metal-to-metal mounting on a common frame or base shall be permitted.
Exception No. 1: The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26.
Exception No. 2: A listed self-contained spa or hot tub that meets all of the following conditions shall not be required to have
equipotential bonding of perimeter surfaces installed as required in 680.26(B)(2):
(1) Is installed in accordance with manufacturer?s instructions on or above grade.
(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top
rim of the spa is greater than 28 inches (71 cm).
Informational Note: For further information regarding the grounding and bonding requirements for self-contained spas and hot
tubs, see ANSI/UL 1563 ? 2009, Standard for Electric Spas, Equipment Assemblies, and Associated Equipment.
My understanding is that each state must accept the TIA otherwise it does not hold weight.
 

sbrehler

Member
8/4 for 50 amps? What kind of cable?
I was hoping they made a 4 conductor cable assembly w/ insulated ground...I thought I needed an insulated EGC per 680.21 (A) (1). But upon reading furhter in 680.40 (C) that it can be insulated or enclosed in the sheath of the wiring method. So, that is a #8/3 CU w/ gnd (uninsulated)...50A at 75C...right?
 

sbrehler

Member
I think you should re-read sections 680.40 through 680.44.

Short answer, it seems that you will need an equipotential plane if this hot tub is outdoors. A ground ring is required to be no less than a #2 awg, but why would you want to install one? Flexible conduit is limited to a maximum of 1.8 m (6ft) outside the tub, so 10 feet of flex is a no-no.

As I read the Code, a hot tub installed outdoors shall comply with the provisions of Parts I and II of article 680 except as permitted in 680.42(A) and (B).
My bad...I completely missed sec. 680.40-44. I was fixated on 640.27 (EPB).

Anyway, I was going to run PVC from the disconnect down closer to the tub, THEN flex over.

You state, no smaller than #2, but 640.26 (B) states ...no smaller than #8.

"Why would I want to run the ground ring?" Because the tub is outdoors, and I'm guessing that 680.26 (B)(2)(b)(1)-(4) is the code reference.

Thanks,

Scott
 
T

taylorp

Guest
Normally I would agree, BUT, there is one wrinkle. In this case, 680.42 in the '11 Code has had a TIA published which changes the rules:

Reference: 680.42(B)
TIA 11-1
(SC 11-3-10/TIA Log #1005)
Pursuant to Section 5 of the NFPA Regulations Governing Committee Projects, the National


Fire Protection Association has issued
the following Tentative Interim Amendment to NFPA 70?, National Electrical Code?, 2011 edition. The TIA was processed by Panel
17 and the National Electrical Code Technical Correlating Committee, and was issued by the Standards Council on March 1, 2011,
with an effective date of March 21, 2011.
A Tentative Interim Amendment is tentative because it has not been processed through the entire standards-making procedures. It is
interim because it is effective only between editions of the standard. A TIA automatically becomes a proposal of the proponent for the
next edition of the standard; as such, it then is subject to all of the procedures of the standards-making process.
1. Revise 680.42(B) to read as follows:
680.42(B) Bonding. Bonding by metal-to-metal mounting on a common frame or base shall be permitted.
Exception No. 1: The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26.
Exception No. 2: A listed self-contained spa or hot tub that meets all of the following conditions shall not be required to have
equipotential bonding of perimeter surfaces installed as required in 680.26(B)(2):
(1) Is installed in accordance with manufacturer?s instructions on or above grade.
(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top
rim of the spa is greater than 28 inches (71 cm).
Informational Note: For further information regarding the grounding and bonding requirements for self-contained spas and hot
tubs, see ANSI/UL 1563 ? 2009, Standard for Electric Spas, Equipment Assemblies, and Associated Equipment.
Augie:

Thanks for the info. I did not know about the TIA.
 

sbrehler

Member
My understanding is that each state must accept the TIA otherwise it does not hold weight.
So, the TIA is suggestive? Not authoritative. :?

Back to my problem then...

Is it required to do a perimiter EPB around this tub and bond the water? It seems that there is a lot of controversy about this...or, so it seems. Would I just be better off contacting the AHJ and see what they want?

Thanks,

Scott
 

hillbilly1

Senior Member
Location
Atlanta,Ga
I would check and make sure it is 120/240, mine is 60 amp 240 volt only, you may be able to delete the neutral after it has terminated at the gfci.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
Scott- sorry I didn't realize it was you asking the question. In NC where we are the TIA is not accepted according to Ron Chilton. The tub does need an epb and the water is generally bonding thru the hot tubs system- I have never had to bond the water on a hot tub.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Flexible conduit is limited to a maximum of 1.8 m (6ft) outside the tub.
I wonder what the justification for that requirement is? What if you are feeding a tub that is sitting on an existing deck and using LFNMC on the underside of the deck was about the only option?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
I wonder what the justification for that requirement is? What if you are feeding a tub that is sitting on an existing deck and using LFNMC on the underside of the deck was about the only option?
In that case you may have to pull up a few deck boards and strap pvc. LFNMC is Limited to 6' for hot tubs-- no exceptions but I am not sure why that is a rule.
 

witkowcj

New member
Location
Chesterfield, NJ
clarification on the TIA

clarification on the TIA

We are also having an self-contained hot tub installed and the inspectors says it does not have to be bonded as long as it meets the criteria of the TIA. It will be installed in accordance with manufacturer?s instructions on or above grade since it will be sitting on top of a hardscaped patio. I'm having trouble interpreting the second criteria.

(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top
rim of the spa is greater than 28 inches (71 cm).

Can someone help me understand what these measurements are. I've had three certified electricians all tell me something different with respect to bonding this tub and I don't want to finish the patio and then be told I have to pull it up. Some information:
The tub is approximately 36 inches high and will sit on top of the patio. There is a retaining wall for a flower bed 15 inches away on one side but it is only 12 inches highso it won't be level with the top rim of the spa. There is an existing deck that is about level with the rim of the spa but it is 57 inches away. Am I ok to not bond the tub or do I interpret the above statement that since the flower bed wall is 15 inches away the tub has to be 28 inches higher than the wall in which case we are 4 inches off?

Thanks in advance.
Christy
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
. . . do I interpret the above statement that since the flower bed wall is 15 inches away the tub has to be 28 inches higher than the wall in which case we are 4 inches off?
That is how I read it. The 30 inch number tells me that if a wall is further than that away, then you don't pay attention to it at all. Your wall is closer, so you do pay attention to it. The 28 inch number tells me that you must have that much vertical clearance from the top of the wall to the rim of the tub. You don't have that much clearance, as you pointed out. I think your electrician will not be able to use that exception.
 
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