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Hot Tub wiring - Another question

6K views 29 replies 7 participants last post by  OKDrew63 
#1 ·
I'm installing a 240V/60A hot tub about 65' from the main house panel (200 Amp service). I'm running 6ga THWN wire, 4 conductors, in 1" Schedule 40.

I've got a 60A breaker in the main service panel and running the 6ga wires to a spa panel that has a 60A GFCI in it, along with 2 slots for an accessory circuit or two. I plan on installing a 20A GFCI breaker in this panel and running an outlet and light switch on this circuit (12ga THWN wire in schedule 40 as well.)

So I have a 60A breaker in the main service panel and a 60A GFCI and 20A GFCI running off of it. The spa pulls 48A max.

Do I need to be concerned with the 6ga wire being undersized for the 60A and 20A GFCI's?

Do I need a larger breaker at the main service panel, and if so, what size should I have gone with?

Thanks for the help.

This is the spa panel I'm installing.

http://www.amazon.com/gp/product/B000NCV07C/ref=oh_details_o02_s00_i02
 
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#2 ·
I'm installing a 240V/60A hot tub about 65' from the main house panel (200 Amp service). I'm running 6ga THWN wire, 4 conductors, in 1" Schedule 40.

I've got a 60A breaker in the main service panel and running the 6ga wires to a spa panel that has a 60A GFCI in it, along with 2 slots for an accessory circuit or two. I plan on installing a 20A GFCI breaker in this panel and running an outlet and light switch on this circuit (12ga THWN wire in schedule 40 as well.)

So I have a 60A breaker in the main service panel and a 60A GFCI and 20A GFCI running off of it. The spa pulls 48A max.

Do I need to be concerned with the 6ga wire being undersized for the 60A and 20A GFCI's?

Do I need a larger breaker at the main service panel, and if so, what size should I have gone with?

Thanks for the help.
everything seems legit so far.... The disconnect needs to be located 5' from the tub. FYI....
 
#3 ·
Oh, yea, I'm burying the schedule 40.

No worries about any temp coefficient of 4 wires in the conduit when underground and driving the need to have larger wire?

Anything about the breaker being 125% of continuous or non-continuous load?

I've got someone putting a bug in my ear, that's what's driving me doubting myself since I'm not electrician - he's not one either, but an electrical engineer.

Thanks for the reply Stick.
 
#9 · (Edited)
No worries about any temp coefficient of 4 wires in the conduit when underground and driving the need to have larger wire?
He is talking about ampacity adjustments when more than 3 current carrying conductors are installed in a conduit. You do not have more than 3 current carrying conductors. Again he is not schooled properly to interpret what he is reading.

Anything about the breaker being 125% of continuous or non-continuous load?
I think your engineering friend is trying to read a copy of the NEC but lacks the practical experience to interpret it correctly. I think he must be reading this for branch circuits. You do not have any continuous loads.

210.20 Overcurrent Protection. Branch-circuit conductors
and equipment shall be protected by overcurrent protective
devices that have a rating or setting that complies
with 210.20(A) through (D).


(A) Continuous and Noncontinuous Loads.
Where a
branch circuit supplies continuous loads or any combination
of continuous and noncontinuous loads, the rating of
the overcurrent device shall not be less than the noncontinuous
load plus 125 percent of the continuous load

I've got someone putting a bug in my ear, that's what's driving me doubting myself since I'm not electrician - he's not one either, but an electrical engineer
 
#10 ·
I'm installing a 240V/60A hot tub about 65' from the main house panel (200 Amp service). I'm running 6ga THWN wire, 4 conductors, in 1" Schedule 40.
That's fine but the ground does not need to be 6 awg, it does need to be insulated as your running a feeder to a panelboard that is supplying a spa/hot tub. For 60 amp circuit breakers protecting a feeder you can use 10 awg THWN copper for ground as long as the distance your running does not have to consider voltage drop for the conductors..


I've got a 60A breaker in the main service panel and running the 6ga wires to a spa panel that has a 60A GFCI in it, along with 2 slots for an accessory circuit or two. I plan on installing a 20A GFCI breaker in this panel and running an outlet and light switch on this circuit (12ga THWN wire in schedule 40 as well.)

So I have a 60A breaker in the main service panel and a 60A GFCI and 20A GFCI running off of it. The spa pulls 48A max.

Do I need to be concerned with the 6ga wire being undersized for the 60A and 20A GFCI's?
Not likely

Do I need a larger breaker at the main service panel, and if so, what size should I have gone with?
6 awg thwn copper is good for 65 amps in conduit ... you can protect that with a 70 amp breaker if you want per NEC 240.4(D). The 60 amp gfci at the spa panel is protecting the branch circuit for the spa which is max 48 amps. So your fine there. The breaker at the main panel will see the spa and the secondary 20 amp gfci branch circuit. If the spa was pulling 48 amps and you were operating something on the 20 amp gfci that was pulling 12 amps you would be pulling 60 amps through the 60 amp breaker at the main panel. This would not trip the breaker and both at the same time is unlikely. If you think other wise then install a 70 amp breaker to protect your panelboard feeder.
 
#11 ·
That's fine but the ground does not need to be 6 awg, it does need to be insulated as your running a feeder to a panelboard that is supplying a spa/hot tub. For 60 amp circuit breakers protecting a feeder you can use 10 awg THWN copper for ground as long as the distance your running does not have to consider voltage drop for the conductors..
Stubbie, every hottub i've ever wired, the manufacture required a full size EGC, so, #6 is highly recommend for the EGC, even though it is a silly requirement.
 
#15 ·
Be gentle, even though he's an engineer, he is my son. :)

He'll be over at the house today helping me get the electric squared away.

So at worst, I may WANT to upgrade the main panel breaker to 70A. At least that's what I'm getting from the conversation here.

Thanks for the info and clarifications, it's helped me quite a bit.
 
#21 · (Edited)
The spa is a packaged unit. The manufacturer specifieds the maximum load is 48 amps. So the branch circuit conductors and OCPD for the spa must be sized accordingly. Any continuous duty or non-continuous duty equipment is taken into account by the manufacturer if any exist.

Now if I were supplying a single motor for a pool for example it is required to size the branch circuit conductors to 125% of the table FLC of that motor if continuous duty application. A pool pump for residential would not be continuous application IMO unless you make it that way.
 
#22 ·
The spa is a packaged unit. The manufacturer specifieds the maximum load is 48 amps. So the branch circuit conductors and OCPD for the spa must be sized accordingly. Any continuous duty or non-continuous duty equipment is taken into account by the manufacturer if any exist.

Now if I were supplying a single motor for a pool for example it is required to size the branch circuit conductors to 125% of the table FLC of that motor continuous or otherwise.
And 125% is the reciprocal of 80%.... just adding my 2 cents. :) and I agree with the above... :)
 
#26 ·
After discussions and further reading, we agreed that what I already had planned for the install was good, but with a possible upgrade to the main panel breaker to 70 amps. He still feels that with the conductors in conduit underground, current capacity will be derated.

We got the conduit in the trench with a couple pull boxes, pulled the conductors and got everything wired in both panels. He did the panel wiring, which was much appreciated on my end.

The major pain was getting a pull rope pulled with a fish tape. We ended up using an old trick I read about a while back, we tied a napkin onto a small string and sucked it through the conduit with the shop vac, then tied the pull rope onto the string and pulled it the rest of way through the conduit. This was after we cut the conduit to find the fish tape. DOH!

Pulling the wire was the easy part. Checked voltage at the spa panel and we look good, just need to see what happens when I apply a load.

Thanks for all the info.
 
#27 ·
UPDATE....

Got the tub set and wired last night - finally. Filled it with water, flipped the breaker, turned on both pumps and the blower with the heater running and no problems. The deck didn't even collapse, although it creaked a few times during fill up (370 gal). The 20A accessory circuit is wired and operating as well, lights were on with the tub running (10 small LEDs, 12vdc) and everything stayed humming along. I think I'm good to go, just need to finish up the privacy panels on the deck.
Thanks for the help.
 
#30 ·
"The deck didn't even collapse".

That was a bit of a joke on my part since I built the deck myself. I was worried about ALL of the project (I have a tendency to do that) but so far, there seems to be no issues. The deck is solid, the tub is level and there has been no creaking from anything moving or squatting anymore. We've been in the tub several times over the weekend. 2x8 joists, 12" OC, on 3 beams under the tub. Each beam is on 3 concrete piers 2' deep (Oklahoma) and I've got 2x6 decking on top of that. The tub is 7'6"x7'6".

Seems like the 6 ga to the panel and the tub is carrying the load well. I've learned a lot on this project, but not sure I'd want to do it again.
 
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