Hot tub through subpanel/generator for power loss protection or...

[watson524]

Hi all,

Starting to prep for new hot tub install. Would like to go through subpanel that a generator powers in case of power outages figuring I could run heater and circ pump if need be but it's turning into possibly more hassle than I had hoped (can easily be done, just need to upgrade main breaker that feeds subpanel from 60a to 100a). Anyone ever done this? Or if I don't go through generator panel, is there a way to hook up the circ pump separately only during power outage to circulate water? Alligator clips somehow?

thanks!

[DaveMc]

The below link is to a forum where each facet of construction is a separate forum.  Your question in my opinion could be better addressed by electricians who frequent this forum and are up on the NEC.  I would ask this question there.  Irf you intend to change out a sub panel breaker from 60 amp to 100 amp then you need to review and possibly resize the wires and the size of the wires will be affected by the distance from the main service.

http://www.diychatroom.com/private.php?do=showpm&pmid=228011

[watson524]

I actually did post there but didn't get a response. If I up from 60 to 100, I would definitely change the wires feeding the subpanel (which is directly under the main panel so no loss of voltage over distance) from #6 to #4 or possibly #3 (I'd have to look up what's required).

I was just looking to see if anyone on the hot tub specific forum runs off a subpanel/generator. The place I'm buying it from did say if need be (i.e. expected outage for longer than a day or so) they could come up with a portable heater for the cabinet area or drain it and blow out the lines (which I can do myself, tho it is nice of them to make this service available, makes me even more comfortable with the dealer we picked). But still wondering if anyone on the hot tub forums has ever run the circ pump off separate power to keep things moving since I'm more concerned about water movement and less concerned about actual water temp.

I see on the sundance website (I'm buying a Jacuzzi brand tub) where they say:
" If you have a generator:

Plug an extension cord from the generator into a submersible pump, and place the pump in the hot tub. The heat from the pump will add to the water plus keep the water circulating, preventing it from freezing.
Another option is to use the generator to run a space heater or 100 watt light bulb. Place the heater or bulb into the equipment area (Inside of the cabinet) of your spa and run for a few hours at a time."

I have a submersible pump and can run a light in the cabinet but I don't get how a pump is going to circulate the water in the lines. It's fine for the water in the main tub (just let the pump dump out right back into the tub vs over the side) but how does that help what's in the lines?

thanks!

[Dr. Spa™ Ret.]

Enough heat will radiate out from the main body of the water to keep the lines from freezing. Remember, they only need to be maintained just above 32 degrees to keep from freezing.

[watson524]

Huh ok... I was thinking about having to move water since we've been known to have air temps around 0 and have the power go out. But perhaps the lightbulb trick is sufficient for that (hey it works for boaters in the bilge area)....

[DaveMc]

Well, in your environment--you might want to consider a "stand by emergency generator"---one that is capable of backing up all or a portion of your needs.
A second choice could be a standby permanent or portable generator just for the hot tub.
I would opt for the one backing up your main service panel---I would not want to be forced, during terrible weather to go outside and deal with a 5' hot tub!--but that is just me.
The more economical way would be a standby generator dedicated to the hot tub--with a transfer switch preferably---as you may be gone when the need arises---but it could be mannual.
Here's a write up on generators:
http://learningcenter.statefarm.com/safety-2/back-up-generators-for-emergencies/

[watson524]

We have a generator that'll do a good portion of the house (it's a portable one we manually switch over). Covers the well, hot water boiler, fridge, key rooms for outlets/lights. Adding the permanent, autoswitch ones are out of our cost range at this time, tho definitely on the list for the future.

The issue is that any portable type generator that's "reasonably" priced for us can't handle 60a (70 is about the biggest they make and those are expensive). Our current one can handle 45a. At full systems going, circ pump, heater and 2 pumps, we would be about 48a on the new hottub. If we just needed heat and circ pump (which is enough in a power outage), the we'd be looking at about 23a based on the size of the heater and the 0.7a draw on the circ pump. So in theory, I could get a dedicated generator to wheel out and use for the hot tub (I get it doesn't solve the issue on if I'm away but that's not something that happens in the winter really and I'd get a friend involved if need be) but it still leaves the question.... can I somehow hook up a cord to a 220v outlet on a portable generator to a hot tub? I mean there MUST be a way to do this right? That's how stores can move tubs around for wet testing and such but how does it work? Just take the cord's wires and put them where the wires from the spa panel goes in? i.e. remove wires from house and attach ones from cord to generator? In my head that works but it doesn't clear the CGFI issues (tho any generator of this size I've seen have a GFCI breaker on them so maybe that would be exactly how we'd do it).

And I know that if you didn't have to remove the house wires to attach the generator wires, I'd have to be sure to shut off the breaker in the main panel and the spa panel to prevent a backfeed situation when the power company power came back on.

[DaveMc]

There is most likely a "Manual" or "automatic" ---"transfer switch"---that would work with a portable generator-(you already have one)--which would need to supply, as you say, 30 amp +/-.
So in this situation interrupt the 3 wire going to the tub from the gfci and run thru a transfer switch that will accommodate a 30 amp generator.  Then run the 3 wire from the generator--(a ground and or neutral may need to be employed also for the generator)-------Sounds so simple!---But I would run it by an electrician who has installed transfer switch's and generators.

An outside the box avenue would be to introduce a heat exchanger off you hot water heater and ---2 loops---one at HW and one at spa water with a circ pump on each!!!--maybe a 110 circ pump (which brings us back to temp electricity--never mind!)

[watson524]

Our hot water is fine during an outage because it's on the generator, and the TACO circ pumps have very little draw so it wouldn't tax the current generator but getting a loop out to where the hot tub is going is something entirely different.

I'm going to ask our electrician friend who's hopefully going to make a trip up here to "bless" whatever we do before I connect the hot tub about this for future purposes. For now, I think I'm going to just move a few 15a circuits down to the generator panel to free up the slot I need on the main panel to add the 60a breaker and go from there. If there's a situation where we are at freeze risk (i.e. out of power a few days or gone during cold months) I can just dump the hot tub and blow out the lines (or hit the lottery and upgrade to a whole house, auto transfer generator). I mean in theory, there's no reason I couldn't have a spa panel box with 2 60a gfcis (or a 60a and a 30a is likely the better option since wire would be sized for the 60a and more than adequate for the 30a) in it just like the 2 60a breaks in my subpanel with a lock switch between them (so both canNOT be open at the same time) and power one breaker with a cord like the one currently going from our subpanel to the generator (#6 rubber cord I think it is). So then I retain the GFCI, never have to touch the wiring at the hot tub, I'd just shut off the breaker from the house feed, open the breaker to the generator, hook it up with the NEMA #14-30 plug or whatever the generator requires and away we go. Hey I like that idea!!!

[DaveMc]

A man with a plan--happy tubing!!!

[watson524]

Had a chat with an electrician that did some work at our house a few years ago (nice when contractors call back right away). He said there's nothing WRONG with running it through my current subpanel to the generator but like I suspected, it'd be too much for the generator if say the tub heater/cir pump came on at the same time as the well pump and fridge. It'd trip the breaker on the generator itself.

Liked our idea of a subpanel outside on the leg of the deck that's just like the one I have in the basement. 60a in the main panel, 2 60a regular breakers in the new subpanel, one wired from the new 60a in the main panel, one wired to a rubber cord with appropriate plug end and lockout device between the two so it's one or the other providing power. Then a 60a GFCI breaker in that new subpanel that's wired to the tub itself. Keep the rubber cord handy and if power goes out, hook up generator to cord, flip breaker to power from generator and tub heater and circ pump can keep going just fine.

I think I may run #4 wire from the main panel to the new subpanel given it's about 55' but I have to check the voltage drop over that length on 60a. From the new subpanel to the tub itself can be #6 since it's close.

He said he'd be happy to come take a look at things after we installed it all before we power up the tub just to make sure we have the grounds and neutrals and all going to the right places. I do need to think about how the GFCI breaker wires up in the subpanel but I think the pigtail will go to the buss bar where it would go if it were in the main panel.

[Dr. Spa™ Ret.]

In your experience, how ofter does power go out, and more importantly, how long does it go out for?

[watson524]

In your experience, how ofter does power go out, and more importantly, how long does it go out for?

You ask because you're sitting there thinking "why is this nutball going through all this rigamaroll for something that might happen once a year for a day or so? she must be nuttier than a fruitcake!" right?? LOL!

Truth be told, we've lost power each winter for the past 10 for at least 18 hours at a time. BUT we've also had a few winters where we've been out 2 - 3 days at a time (once it was twice in the same winter). Our longest outage was 5 days but that was in May.

Since they've just ripped up my 100 acre property to install obnoxious 230kW power lines 150' tall that look like crap and tell us this will help cut up the grid and make for less power downtime (BULL!!! in reality, it's sending power to NJ/NY) I darn well better not have extended outages every again.

So net net, the more I think of this, in my head I'm 75/25 split on even needing to worry about a generator on the tub (with the 75 part being on the side of 'just wire it up as normal and forget the generator system knowing I can dump the tub, drain the pumps and blow out the lines if need be'). Can I assume you'd agree with my 75% thinking?

[Dr. Spa™ Ret.]

I'm not thinking that at all. I think it's a very wise idea to prevent your spa from freezing when you live in and area where the temps get low, and you have frequent, or possible frequent power outages. But, I do think, you're over thinking it. ALL you have to do is keep it from freezing. You don't have to keep it at 104 degrees....... JUST over 32 degrees. And, you only need to do so for maybe, 3 days. This is really easy. All you need to do is wire a 100w incandescent light bulb directly to a generator and put it in equipment compartment (when ever the generator kicks on, the light lights up). When the power goes out, the main body of the spa is going to be at temp. Even at 0 degrees outside, it would be over a week, probably 2 weeks, for this to freeze. The main body of water will radiate plenty of heat outwards to prevent the plumbing around the spa from freezing. The only real area of concern is the equipment compartment, which typically is uninsulated and vented. A 100w light bulb will generate enough heat to keep that area from freezing.

[Tman122]

Every power outage that we have had in the "winter" has happened in early or late winter because the temp is close to freezing and it causes an ice storm instead of a snow storm. This ice builds up on power lines and trees to cause downed lines and outages. But the temp is usually in the 30-40 degree range at the time and a hot tub will last a long time without power in those temps. And a small heat source in the equipment area (trouble light) can maintain enough temp to prevent freeze for weeks at those temps.

Doc is right, you are over thinking it. By all means supply a 15 amp outlet by the tub. And get yourself a small electric heater or trouble light. And have a plan for possibly draining and evacuating lines if need be. If the circ pump is 110 V getting it to run by by passing the control would be easy to figure out. But I don't think you need to.