Does this hot tub need equipotential bonding

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crtemp

Senior Member
Location
Wa state
I hooked up a hot tub today that a customer has buried in the ground (mostly). It is actually half hot tub and a half pool that generates a current so you can swim in place. It is about 12 feet long and about 5 feet wide divided into two separate sections. He buried it into a hill that slopes at a 45 degree angle so all sides are underground except for the side that has the electrical connections. Since this is now buried underground does it now need a copper conductor grid? There will be no concrete or pavers just dirt around the unit. I'm a little unsure of the perimeter surfaces section of article 680.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Is this really a hot tub? Depending on the depth of the tub above the ground will determine if it needs an equipotential bonding. it also depends on which code cycle you are on. IMO it seems like it needs the equipotential bonding
 

crtemp

Senior Member
Location
Wa state
Is this really a hot tub? Depending on the depth of the tub above the ground will determine if it needs an equipotential bonding. it also depends on which code cycle you are on. IMO it seems like it needs the equipotential bonding

it is above the surface maybe 6" at most. We are on the 08' nec
 

shortcircuit2

Senior Member
Location
South of Bawstin
Yes you need a perimeter bond under 680.26(B)(2) of the 2008 code, paved or unpaved. 2008 allows a single #8 to follow the contour of the pool 4-6 inches down.

This install would need one also under the 2011 and 2014 code.
 

crtemp

Senior Member
Location
Wa state
Yes you need a perimeter bond under 680.26(B)(2) of the 2008 code, paved or unpaved. 2008 allows a single #8 to follow the contour of the pool 4-6 inches down.

This install would need one also under the 2011 and 2014 code.

There are 2 control boxes under the tub. One for the pool portion and one for the hot tub portion. Do I just land one end on one and the other end on the other one where the ground wires terminate?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I would make a continuous loop around the tub and then continue on to both control panels and the pumps.

Agree on the equipotential bond loop. If the control panels are greater than 5ft from the edge of the inside wall I see no reason the eq. bond needs to connect to them.(680.26(B)(7) exception 2)
 

crtemp

Senior Member
Location
Wa state
I would make a continuous loop around the tub and then continue on to both control panels and the pumps.

All the pumps are already bonded from the factory. The control boxes have ground bars attached to the outside of the boxes and lots of various grounds come off it to all the various pumps underneath. If I don't land the bond loop on the ground bar of these boxes, I'm not sure what else I would attach it to.
 

kwired

Electron manager
Location
NE Nebraska
All the pumps are already bonded from the factory. The control boxes have ground bars attached to the outside of the boxes and lots of various grounds come off it to all the various pumps underneath. If I don't land the bond loop on the ground bar of these boxes, I'm not sure what else I would attach it to.
That is likely where they intended you to land your EP bonding conductor(s) to other equipment.
 

shortcircuit2

Senior Member
Location
South of Bawstin
If the control panels are greater than 5ft from the edge of the inside wall I see no reason the eq. bond needs to connect to them.(680.26(B)(7) exception 2)

I disagree. If the control panels are associate pool equipment, they require bonding regardless of distance from tub/pool.

680.26(B)(7) is for metal that is not associated pool equipment such as a fence...or a gutter...a metal bulkhead.

I have always used the external ground bars provided by the manufacturer as a point to land my #8 solid bonds. You could also used listed grounding connecters and tap off your #8 bonding loop to pick up anything else you need to bond.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I disagree. If the control panels are associate pool equipment, they require bonding regardless of distance from tub/pool.

680.26(B)(7) is for metal that is not associated pool equipment such as a fence...or a gutter...a metal bulkhead.

I have always used the external ground bars provided by the manufacturer as a point to land my #8 solid bonds. You could also used listed grounding connecters and tap off your #8 bonding loop to pick up anything else you need to bond.

I can't find the requirement for bonding the control cabinets.
 

kwired

Electron manager
Location
NE Nebraska
I disagree. If the control panels are associate pool equipment, they require bonding regardless of distance from tub/pool.

680.26(B)(7) is for metal that is not associated pool equipment such as a fence...or a gutter...a metal bulkhead.

I have always used the external ground bars provided by the manufacturer as a point to land my #8 solid bonds. You could also used listed grounding connecters and tap off your #8 bonding loop to pick up anything else you need to bond.

I can't find the requirement for bonding the control cabinets.

I'd say if it is in the pool area 680.26(B)(6) would require it.
Keep in mind the last sentence of 680.26 - "An 8 AWG or larger solid copper bonding conductor provided to reduce voltage gradients in the pool area shall not be required to be extended or attached to remote panelboards, service equipment, or electrodes." So if the panel is not in the immediate pool area I'd say it doesn't need connected to the equipotential bonding system, but still needs equipment grounding conductor run to it.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Thanks.
That's the wording I was searching.
We may be getting into a grey area as to "control cabinet", but most the pools I see now use a combination sub-panel with built-in controls for
lights, salt water, etc.
It is my thinking that since that is a remote panelboard it does not need a equi. bond connection unless, as you say, it falls into the pool area,
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Thanks.
That's the wording I was searching.
We may be getting into a grey area as to "control cabinet", but most the pools I see now use a combination sub-panel with built-in controls for
lights, salt water, etc.
It is my thinking that since that is a remote panelboard it does not need a equi. bond connection unless, as you say, it falls into the pool area,

OP said the control panel(s) are under the tub. That would put them in the "pool area".
Same setup as a regular packaged hot tub.
 
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