Hot Tub circuit plus sockets

[AlanWirral]

Hi guys,

Think i just need another set of brains on this one as i'm goosed :stuart:

Fitting a supply for a Hot Tub tomorrow. Client bought it off Ebay and i must admit it's a belter. The old owner has kindly given us the 30 mtrs of SWA that it has on now to which i'll be using approx 16/17mtrs. Tub needs a 32amp supply btw

NOW this was all well and good. I'm using a spare way on the 4 way CU in the garage which isn't running much else, 4 sockets and 2 Flo's. Then the client (millionare as it happens) sais 'Oh i want 2 double sockets next to the tub aswell' All i was going to do was run the cable into an isolator on the wall and walla. Now i'm not sure how to get around it. Ideally i don't want to run another swa from that board for the extra sockets as i've already done the groundwork and drilled the hole in the garage etc etc

I COULD spur off the room next to the garden but this means only one socket and it will be a pain as there's decking from the outside wall to another short wall with a raised garden, to which decking has been fitted today for the tub.

Is there a way i can use the hot tub supply for the 2 sockets that i'm not thinking of and of course meet the regs?

Thanks in advance

 

[AlanWirral]

Anyone? Very quiet in here tonight

 

[trev]

Depends on how close "Next to the tub" is mate
Next to as in lean out and plug something in or next to as in I'll get out and plug something in (with wet hands and feet etc)

 

[AlanWirral]

They will be far away enough not to be operated from within the tub itself.

 

[PC Electrics]

Check out your BRB for the section on swimming pools. Those sockets need to be min 2m (IIRC) away from the tub.

Why not make the supply 40A and use a small IP65 enclosure with a 20A MCB to supply the sockets?

Don't forget you cannot use any diversity with a tub because the heaters run at full chat for 8 - 24 hours from a cold fill (depending on total water content and heater power). So you'll need the actual max power of the tub to assess your design current.

 

[AlanWirral]

Thanks PC...as it happens I'm just looking at the BRB now. They will be 2 metres away for sure.

The cable is only a 4mm so max 38amps in the method I'm using. I've even told by the engineer max load is approx 30 amps. Don't really like the idea of another DB so might just struggle with spurring off the house. Plus I can see the circuit easily getting overloaded and tripping.

Thanks for the advice.

 

[Engineer54]

Check out your BRB for the section on swimming pools. Those sockets need to be min 2m (IIRC) away from the tub.

Why not make the supply 40A and use a small IP65 enclosure with a 20A MCB to supply the sockets?

Don't forget you cannot use any diversity with a tub because the heaters run at full chat for 8 - 24 hours from a cold fill (depending on total water content and heater power). So you'll need the actual max power of the tub to assess your design current.

Doubtful that the heaters will need to run for that long, about 4 hours is about the norm for hot tubs, maybe a little longer with UK ambient temperatures...lol!!!. But they will include a circulating pump, to continuously past water over the heating elements.

 

[AlanWirral]

Just spoke to the engineer and he said they run perm. at 27amps. I'll stick with comin off the house with one double socket and he can just accept it. Sick of customers especially wealthy ones trying to make me stray from the regs!

 

[PC Electrics]

Doubtful that the heaters will need to run for that long, about 4 hours is about the norm for hot tubs, maybe a little longer with UK ambient temperatures...lol!!!. But they will include a circulating pump, to continuously past water over the heating elements.

Do some maths! A typical medium sized tub with 2000 litres, filled with 12C ambient water heated with 6kW to 42C will take 11.67 hrs.

Bear in mind that when the tub is in use, heat loss is greatest, so the heaters will be on along with all the pumps / lights.

 

[PC Electrics]

I don't see anyone trying to make you stray from the regs! You said he's a millionaire, so presumably he can afford for you to do it correctly!! No reason you cannot design the circuit properly to supply the tub and sockets. You're not stuck with that cable - you can buy some new!! Anyway, there's nothing stopping you supplying sockets with a 40A mcb, as long as they'll take the (min) 6mm cable required.

 

[steve-the-hat]

I'll stick with comin off the house with one double socket and he can just accept it. Sick of customers especially wealthy ones trying to make me stray from the regs!

I would go with a second swa cable and db, as PC Electrics suggested. That way you can stay within the regs AND give the customer what he asked for.

You didn't mention any RCDs, but presumably you are taking care of that at the garage end.

Would "Part P" apply here as the tub is in a domestic garden?

 

[PC Electrics]

Actually, you haven't made any mention of what the client expects to use those sockets for. Might be pertinent to your design to know this.

 

[Engineer54]

Do some maths! A typical medium sized tub with 2000 litres, filled with 12C ambient water heated with 6kW to 42C will take 11.67 hrs.

Bear in mind that when the tub is in use, heat loss is greatest, so the heaters will be on along with all the pumps / lights.

Can't really comment on times in the UK, but in Cyprus rarely does it take more than 4 hours to be upto temp... Not sure about 42C either. My unheated pool gets upto 35C in summer and that's like swimming in bath water...lol!! A fair few litres more than 2000 too.

Must say, many of the Jacuzzi/hot tub's over there, run off the central heating boiler, thru a heat exchanger, with make-up heat via electrical heating. I'll have to ask a mate in Cyprus about heating times (he's all electric) and final working temperatures...

I Dunno, but 42C just seems a little tooooo hot to me ...lol!!

 

[AlanWirral]

Actually, you haven't made any mention of what the client expects to use those sockets for. Might be pertinent to your design to know this.

It matters not what he is going to use them for but I can't see him sticking to the circa. 5amps left before the 32amp breaker trips on this circuit.

I'm coming off the house now anyway so no problems.

 

[Engineer54]

Things must be getting bad in the UK, when you have Millionaires buying secondhand gear off of e-bay!! lol!! Still, i suppose it's one way of being able to stay a millionaire. ...lol!!