Need to run 4 x 3kw hot tubs

[8ballpoolplayer]

Have a customer who wishes to run 4 hot tubs (3kw each) in the garden at their holiday let .. Theyve got single phase supply with 100a .. 25mm tails and 16mm bonding .. was thinking of connecting ip66 sub board with 63a rcd via 16mm swa (10mtr max run) and then 4x sgle ip66 skts in 2.5mm t&e with 16a mcbs on each ..
If anyone has any suggestions on this I'd really appreciate it

 

[Pete999]

What method of earthing exists? why not use RCBOS instead of CBs and swap the 63 A rcd for a circuit breaker to cover the cable you have calculated to be 16mm2?

 

[8ballpoolplayer]

Thanks for reply .. it's a TN-S earthing arrangement ..
Had thought of rcbo's , but there's akready 1 built in to the individual hot tubs supply line
My main concern is whether earthing arrangement is sufficient or not ?

 

[telectrix]

what's your Ze? then calculate the Zdb at the sub, using the R1+R2 value of the intended cable.

 

[8ballpoolplayer]

Good advice .. thanks for replying .. appreciate it

 

[Wilko]

Personal view is remotely located hot tubs may be best on their own TT system, but it may not make sense in your location.

 

[Midwest]

What else is going on in their holiday let D), electrical wise that is. If it has 4 x hot tubs, is it a largish bit of accommodation, do they have sufficient capacity in the 100a supply?

 

[8ballpoolplayer]

It's a large 2 X 16 bed barn , both with separate 100a incoming supply . They're oil heated with oil fired arga cookers, so only running 2x 32a rings , 2x 6a lights , 6a smoke alarms from this board . Other board has same except for extra 32a ring to washroom running 2 washing machines

 

[Midwest]

It's a large 2 X 16 bed barn , both with separate 100a incoming supply . They're oil heated with oil fired arga cookers, so only running 2x 32a rings , 2x 6a lights , 6a smoke alarms from this board . Other board has same except for extra 32a ring to washroom running 2 washing machines

Cool, won't ask what's going on, wanting 4 x hot tubs

 

[Gavin John Hyde]

Only property I have ever come across with 4 hot tubs was a knocking shop / massage parlour.
They had us in to put downlights and panic alarms linked to reception in the rooms. The girls were a good bunch and had a good sense of humour, was funny walking around though with them in lingerie and blokes coming and going avoiding eye contact whilst passing us having a cup of tea when on break.The girls would tell us some very funny stories about the clients... Saw an interesting side to their business but sadly at the same time not every girl in that world is treated so good. I never did find out how the boss got that job but he knew the girls by first names!!!

 

[PEG]

I trust your tester,only had 3mm of it's probe,visible...

 

[Pete999]

I trust your tester,only had 3mm of it's probe,visible...

Even more important was it non contact one

 

[Wilko]

Even more important was it non contact one

With VDE rating as well ...

 

[8ballpoolplayer]

Just like to thank everyone who has replied. . Really appreciate the input .. I decided to run from Henley block with 16mm swa to new sub main with 63a MCB and 4 X 16a rcbos, each supplying 1 socket and then knocked a 1.5m copper electrode in and made it a TT system .. got Ze < 50ohms so happy with how it all works