Hot Tub Instructions SNAFU

11bgrunt

Pragmatist
Location
TEXAS
Occupation
Electric Utility Reliability Coordinator
I got a question today about connecting a hot tub. I have done tubs and pools before, long ago, and felt comfortable enough with my experience to listen. He has the instructions for connecting the spa to a three wire service. There are instructions for four wire that are applied to other models but this is supposed to be three wire.
Connecting to a 60 amp, 240 volt GFCI breaker. Connected load is 47 amps. He says there is no place to connect a neutral wire so I say all loads must be 240 volt. There is one buss to connect all grounding conductors at the spa. Instructions state that a ground rod will be driven and the grounding buss will be connected to that rod. No mention of a EGC or anything that sounded like a grounding wire back to the panel. The recommended wire size for this load is #10cu.
I asked which country? Instructions show USA.
I didn't have anything nice to say about this project and think something is really out of whack somewhere. Has anyone seen Spa instructions that go along these lines? I have not had the instructions in my hands to see if the information was relayed correctly.
I will be forwarding your comments.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
There does not have to be a place to connect a neutral wire if there are in fact no 120V loads.
But there must be an EGC. Simply driving a local ground will not take the place of an EGC.

The "three wire" connection must have the third wire going back to the source! Otherwise it would be a two wire connection, which could not power anything. :happysad:
 

JFletcher

Senior Member
Location
Williamsburg, VA
I got a question today about connecting a hot tub. I have done tubs and pools before, long ago, and felt comfortable enough with my experience to listen. He has the instructions for connecting the spa to a three wire service. There are instructions for four wire that are applied to other models but this is supposed to be three wire.
Connecting to a 60 amp, 240 volt GFCI breaker. Connected load is 47 amps. He says there is no place to connect a neutral wire so I say all loads must be 240 volt. There is one buss to connect all grounding conductors at the spa. Instructions state that a ground rod will be driven and the grounding buss will be connected to that rod. No mention of a EGC or anything that sounded like a grounding wire back to the panel. The recommended wire size for this load is #10cu.
I asked which country? Instructions show USA.
I didn't have anything nice to say about this project and think something is really out of whack somewhere. Has anyone seen Spa instructions that go along these lines? I have not had the instructions in my hands to see if the information was relayed correctly.
I will be forwarding your comments.

The spas I've done recently had a grounding/bonding bar attached to the outside of the controls box for the heater, recirc pump, jet pumps, etc.. You still need an EGC back to the panel (and from spa to LOS disco, it has to be insulated if the spa is outside). #10 might be good to go to the ground rod but sounds undersized for the #4 NM you will most likely be running from panel to the disco. I would have instructions in hand, maybe have the HO snap a few pics of the inside of the control box to make sure the spa is straight 240V and doesnt need a neutral before ordering wire. There should be an internal lug to land the EGC near the ungrounded lugs.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I have never seen a tub require a ground rod. That is absolutely ridiculous. This is the manufacturer trying to cover their butts every way they can. I don't see how a rod is helpful
 

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Engineering
Does he have manual? Ask him for mfg. And model number then see if you can find it on the internet. I believe what I read a lot quicker than what I'm told on lots of things.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't think that it means that you cannot use the disconnect for anything else just because they call it an a/c disconnect.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Not sure if this article helps. It's from an April 2014 issue of EC Magazine :

http://www.pceca.net/images/stories/bonding_hot_tubs.pdf

In addition the spa tub mfr. recommends that you connect # 10cu to a 60 amp GFI breaker/disconnect where the draw is 47A. Just because the mfr. suggests that it doesn't make it correct or Code compliant. However, having said that, they may have a feature built into their control panel where the heaters cannot be on at the same time all the blower & circulator motors are on. So, total draw may not actually be 47A in a worst case scenario.

The other thing is the type of connection terminals that are provided in the spa unit. The last few that I've worked on came with these itty-bitty European terminals where you either have to press down a clip to insert the wire (like a stereo speaker) or you need a jeweler's screwdriver type tool to tighten down the screws. Getting # 8 0r 6 awg properly landed is a chore.

Good luck. Hope everything works out.:thumbsup:
 

kwired

Electron manager
Location
NE Nebraska
(from your quoted magazine article)

In addition the spa tub mfr. recommends that you connect # 10cu to a 60 amp GFI breaker/disconnect where the draw is 47A. Just because the mfr. suggests that it doesn't make it correct or Code compliant. However, having said that, they may have a feature built into their control panel where the heaters cannot be on at the same time all the blower & circulator motors are on. So, total draw may not actually be 47A in a worst case scenario.

If the controls don't allow all components to run at same time then the nameplate should be marked differently if they want to require a 10 AWG supply conductor. If nameplate says 47 amps then per NEC we must provide a minimum of 47 amp conductor plus any other factors that apply to the situation.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
I've done many, many, hot tubs. I ran into one that I couldn't find any place to land the neutral. I finally saw a sticker that said "this requires a 3-wire circuit". To an electrician that could mean 4-wire including the ground. But after researching it, they mean literally 3-wire including the ground. Which of course means no neutral on a 240V circuit.

As for the 47-48A, they don't figure in the 125%. So 48A x 125% =60A
Some say 40A in the specs but plate says 50A. So again they didn't figure in the 125%.
40A x 125% = 50A
 
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