# Pool & Hot Tub Subpanel Amperage



## eddy current (Feb 28, 2009)

My guess without actual nameplate data is 60 won't be enough. Be close, but my guess is it will be over 48 amps of load. (80% 0f 60)

I bet if you did a house load calculation on that place you would be over 100 amps.


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## Loco11 (Jan 23, 2014)

eddy current said:


> My guess without actual nameplate data is 60 won't be enough. Be close, but my guess is it will be over 48 amps of load. (80% 0f 60)
> 
> I bet if you did a house load calculation on that place you would be over 100 amps.


Would I even need the 80% rule? I think the pool pump is going to be the only "continuous load". The spa isn't going to run at full power for more than 3 hours at a time. 

I found a way to take the lighting and receptacle loads out of the equation. I did the wire fill math from the relevant tables. If I pull 2#6 ungrounded, 1#8 grounded, 1#10 EGC, and 2 additional #10 conductors, I would meet the NEC's 40% fill requirements. The two additional conductors would feed the lighting/receptacle loads directly from the main and should survive the voltage drop as #10's. 

If I'm trying to hard here, it wouldn't be the end of the world to find another route, but I'd have to tear up some concrete, per the customer's request.


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## Loco11 (Jan 23, 2014)

Oh yeah, if I pulled the lighting/receptacle conductors from the main, the wet niche would still need to be a dedicated circuit and feed from the sub.


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## flyboy (Jun 13, 2011)

Contrary to popular belief, to be code compliant, you can't reduce the neutral to #8.


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## splatz (May 23, 2015)

You'd really consider doing something marginal at best to avoid running another conduit across the basement? 

Is this kind of thing usually your call?


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## flyboy (Jun 13, 2011)

IDK, I might be wrong about that...
Default
Here is the relevant code section, note that it applies to services and feeders.

Quote:
220.61 Feeder or Service Neutral Load.

(A) Basic Calculation. The feeder or service neutral load
shall be the maximum unbalance of the load determined by
this article. The maximum unbalanced load shall be the
maximum net calculated load between the neutral conductor
and any one ungrounded conductor.

Exception: For 3-wire, 2-phase or 5-wire, 2-phase systems,
the maximum unbalanced load shall be the maximum net
calculated load between the neutral conductor and any one
ungrounded conductor multiplied by 140 percent.

(B) Permitted Reductions. A service or feeder supplying
the following loads shall be permitted to have an additional
demand factor of 70 percent applied to the amount in
220.61(B)(1) or portion of the amount in 220.61(B)(2) determined
by the basic calculation:

(1) A feeder or service supplying household electric
ranges, wall-mounted ovens, counter-mounted cooking
units, and electric dryers, where the maximum unbalanced
load has been determined in accordance with
Table 220.55 for ranges and Table 220.54 for dryers

(2) That portion of the unbalanced load in excess of 200
amperes where the feeder or service is supplied from a
3-wire dc or single-phase ac system; or a 4-wire,
3-phase, 3-wire, 2-phase system; or a 5-wire, 2-phase
system

(C) Prohibited Reductions. There shall be no reduction of
the neutral or grounded conductor capacity applied to the
amount in 220.61(C)(1), or portion of the amount in (C)(2),
from that determined by the basic calculation:

(1) Any portion of a 3-wire circuit consisting of 2 ungrounded
conductors and the neutral conductor of a
4-wire, 3-phase, wye-connected system

(2) That portion consisting of nonlinear loads supplied
from a 4-wire, wye-connected, 3-phase system


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## Loco11 (Jan 23, 2014)

splatz said:


> You'd really consider doing something marginal at best to avoid running another conduit across the basement?
> 
> Is this kind of thing usually your call?


Fair question. I'm kind of here to figure out how marginal it might be. If it meets code and serves the intended function, then I wouldn't consider it marginal. It would save the customer a considerable amount of money and me a considerable amount of crawling around the attic in the summer. (I know...boo hoo hoo :no. I have a feeling that the load from the pool motor and the spa may be just fine on a 60A breaker, but I like to make things happen economically (and safely for sure). It's part of the fun of the trade for me. But I admit that I sometimes need to turn to the advice of others for sounder judgement. If it's too borderline and the circuit is likely to be overloaded, then I'll move on to Plan B. 



flyboy said:


> Here is the relevant code section, note that it applies to services and feeders.
> 
> (A) Basic Calculation. The feeder or service neutral load
> shall be the maximum unbalance of the load determined by
> ...


It would be a feeder so I should be able to reduce the neutral at least up to his point if I determine the "maximum unbalance of the load". Because I'm primarily dealing with 240v loads, the unbalance should be minimal.

Thanks for the quick feedback guys!


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## telsa (May 22, 2015)

Loco11 said:


> Would I even need the 80% rule? I think the pool pump is going to be the only "continuous load". The spa isn't going to run at full power for more than 3 hours at a time.
> 
> I found a way to take the lighting and receptacle loads out of the equation. I did the wire fill math from the relevant tables. If I pull 2#6 ungrounded, 1#8 grounded, 1#10 EGC, and 2 additional #10 conductors, I would meet the NEC's 40% fill requirements. The two additional conductors would feed the lighting/receptacle loads directly from the main and should survive the voltage drop as #10's.
> 
> *If I'm trying to hard here, it wouldn't be the end of the world to find another route, but I'd have to tear up some concrete, per the customer's request*.



Try horizontal boring.

What are you talking about ? 20-feet ?






There are other tools out there, too. Many can be rented.


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## Loco11 (Jan 23, 2014)

telsa said:


> Try horizontal boring.
> 
> What are you talking about ? 20-feet ?
> 
> ...


I do want to try this, but I'd still have to cut some concrete to even get access to use the tool at this location.

I also didn't double check.  That 6AWG is good for a 65A load and I could use a 70A breaker. Still a no go?


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## telsa (May 22, 2015)

Loco11 said:


> I do want to try this, but I'd still have to cut some concrete to even get access to use the tool at this location.
> 
> I also didn't double check.  That 6AWG is good for a 65A load and I could use a 70A breaker. Still a no go?


With rare exception, push-on breakers in load centers < 100A carry only a 60 degree rating.

This is not a hard and fast rule, as I've seen some [SqD] breakers with dual ratings. (60/75)

You'll have to look into this. [ Push on breakers are not my 'thing.']

I'm way too lazy to run the numbers, but you might get away with...

(2) #4... Hots
(1) #10... Neutral ... even #12 if there's only one L-N load. ( a receptacle )
(1) #8... Grounding//Bonding

&&&

As for horizontal boring, don't assume that you'll be driving 10-foot sticks. If one had to link up four-foot sticks, it'd still be cheaper than messing with the existing concrete.

( Trenching back 15-feet so that I can shove full ten-foot sticks makes no sense to me. )


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## telsa (May 22, 2015)

One last option:

Go with 240 VAC ... only.

Then set a dinky 240/120 VAC transformer out near your loads. ( SDS rules )

These days, with LEDs and some 15A L-N receptacles, you won't need much.

Kick your options around.


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## Roger123 (Sep 23, 2007)

Loco, 

"On another note, it looks like I may recommend a service upgrade."

Your best advice.


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## Dennis Alwon (May 9, 2009)

You are an apprentice. How are you doing this job. I assume you are not getting a permit but you should avoid this situation.


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## trentonmakes (Mar 21, 2017)

Look into a jandy panel or similair. 60 amps should be more than enough and home owner can control lights and spa via remote.






Seen As A Tiny Blip From Space


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## Drsparky14 (Oct 22, 2016)

Loco11 said:


> Long time lurker here!
> 
> Ok, so my customer is looking to add a lighted gazebo with a nearby hot tub in her yard. There will also be 3-4 convenience receptacle locations in the yard, gazebo, & hot tub vacinity (6-10ft away).
> 
> ...




#6 thhn is good for 70 amps. 



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