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Posted By Topic: Swim Spa needs 48A supply?

Feb 11 2018 11:50

Hi Guys,

Firstly thanks Ron for this great forum and the effort you make to helping educate electricians rather than chastise them :)
I have a client who has just bought a huge swim spa. She has a small 2 bed house. 63A mains. The problem is the swim spa says it needs two 24A cicuits (48A total). does this sound right because surely this would mean majority of houses would need their mains upgraded?? at this stage im looking like i will have to upgrade the main to 35mm for 100A off the street (40m run) and also replace her old ceramic fused switchboard. Any help would be appreciated. Thanks

Feb 11 2018 12:31

11000 watts ? sounds a bit strange . name and model of spar pool ?

Feb 11 2018 13:33

It’s an endless spa model e500 fitness. It says 2x24a supply’s

Feb 11 2018 13:57

Yes it is a bit of a beast. But impressive.
Look at the loading for the rest of the house. I’m guessing 2 or 3 phase isn’t available. Depending on the rest of the house loading you could limit max demand with a 63A mcb and rely on that. But if they can afford that beast and the power station that powers it I’m sure they will have quite a few power hungry appliances.
Perhaps get them to upgrade to 3 phase. Would possibly be the simplest and most cost effective.
Might pay to discuss how much an hour it is to run. I’ve done this with a customer when they got a steam room for a bargain price. When I told them running costs they decided to on sell it :-)

Feb 11 2018 14:04

It’s a little 2 bedroom house so not much in the way of fancy appliances but possibly in the future. 3 phase would prob end up too expensive with 3 times the line charges vs upgrading to 100a single. I had thought of the mcb option to see how it goes but a trench has already been dug (full of water today with this rain). If anyone else has some options or have installed one of these before it would be good to hear how it was done.

Feb 11 2018 15:38

The prob is now the pits on the street only take 25mm cable and I have 35mm to have put in. Do you have to put 25mm tails on the ends or some other way? Sorry I don’t do houses very often I have an industrial background

Feb 11 2018 15:52

I don’t think the above assumptions are right. The heating element is 3000 W (approx 13 a).

I would say it’s more like 2 x 3 kW elements so 2 x 6 mm2 would be about right.

Feb 11 2018 15:57

Hi Daniel, yeah in the manual it shows the wiring diagram with 2 6mm circuits with 24a breaker, that’s why it just seems so confusing (to me anyway)

Feb 11 2018 16:03

And also, these spas will have a selection switch or fuse to downgrade to one supply and will heat on one element if there’s a supply issue.

Feb 11 2018 16:14

I think I will Ring endless spas tomorrow and ask them how they usually install them or get name of one of their installers to find out. I just think it’s crazy to have to upgrade mains because surely they wouldn’t sell many. And the client isn’t intending on staying at this new place for long.

Feb 11 2018 18:21

Don't forget about the pumps. Download and look at the specs. 3KW heater, 5KW hydraulic power unit.
Then a 2.5 HP Continuous Duty;5.2HP breakdown Torque 1 speed pump. (Not too sure about what that means).
1.07 hp circulating pump.
Plus whatever the ozone unit uses. May need to see if this is allowed to be connected in a residential area and if so if any special conditions.

Feb 11 2018 19:16

I did a 2x230VAC spa supply once. Followed manufacturer instructions to the letter. One RCBO would trip constantly. Turned out the neutrals were linked in the spa. While the instructions showed 2x two pole GFCIs it actually required 1x four pole GFCI. Totally recommend talking to the manufacturer/distributor before you start.

Feb 11 2018 22:12

I reckon it will pull 48A at full chat if the one at my place is anything to go by.
My housemate said it always tripped the breaker (20A) when the jets were on, which was a concern as it was on a 1.5mm flex plugged into a 10A RCD PowerPoint! I opened it up, and found a 3kw heater plus 2 9.6A pumps! I switched one of these off and just managed to record nearly 24A with a clampmeter before it tripped again. So that would be right, 13A for the element, 9.6A for one pump and an amp and a half for the LED lights, so with everything running it would be pulling over 33A! I told my landlord it's bloody dangerous and needs upgrading from the SB to the final connection, and is currently cold and unplugged until it's sorted. He reckons the bloke he bought it off sold it to him with the 10A plug already on it, so he just plugged it in. Not his fault as such but it shows that people buy these things without any consideration to power requirements! It needs what it needs, they'll definitely learn a lesson!

Feb 11 2018 22:36

PS the one at my place is only a normal 6-8 spa, not a swim spa, so way smaller than that beast you're dealing with!

Feb 13 2018 13:37

I suspect the two feeds are essentially for the big pump for swim mode, and everything else.

Perhaps you could talk to the manufacturer; they may have a load shed mode whereby when the big pump is on the heaters could be disabled...? Might be a lot cheaper for the homeowner than digging up half the world to get a chunky supply in!

Feb 13 2018 17:50

Move to the beach. Might be cheaper.

Feb 15 2018 17:38

Come on Boatie80, get the 10mm out and get it wired up for him, lol

Feb 15 2018 22:26

Further to my questions news is at hand... turns out the spa does have load shed where one cicuits on the other goes off. So a whole lot is stress for nothing :) now the trench just needs to be filled back in with an empty 40mm conduit and draw wire for the future :) thanks for all your help guys much appreciated