60 amp feed for a HOT TUB

[Roger]

Ok have to install one of these,foundations being dug this week.

It needs 2 Live feeds (heaters and pumps) ,neutral and earth.(so i am told)

Depending on load propose 2 RCBO's to feed lives and 4 core SWA probably 6mm to an external IP isolator located within 2 metres of Hot Tub.

Picking up some other information its seems to recommend a earth spike for the Tub.I will terminate the SWA internally TN-S and take to isolator then to Tub.Spike to framework of Tub.

Anyone had experience of Hot Tubs before,did a search and it came back blank !

As always advice welcome,its a large Jacuzzi model.

Lives - red and black ,earth -green and neutral white.

 

[malcolmsanford]

Think you might want to go a little bigger than 6mm for that supply.

Have a look at section 702 of the regs to give you a little more information.

I would in all honesty have the TN-S just protecting the SWA and have the Spa/Jacuzzi installation on the rod. So bring the SWA to the enclosure which I would install either an RCCB/RCD as your double pole main swich and then MCB's to the equipment. I assume something like this will have main water services and these can be bonded at the enclosure.

 

[Roger]

Great thanks for the quick reply.
I am hovering on using 10mm as its going to be about a 15 metre run.It has been modified for UK voltage so now confirmed as requiring only one live feed.That saving on cable is good so will now go the 10mm route.
I will install the IP isolator in zone 2 so 2m from edge of TUB as I have an RCD.On the CU this will be the only item on the RCD so ,so will go directly into that so no need for an MCB.The existing CU only has a main switch and RCBO's so i only have one neutral bar as its not a 17th edition one.

 

[malcolmsanford]

Great thanks for the quick reply.
I am hovering on using 10mm as its going to be about a 15 metre run.It has been modified for UK voltage so now confirmed as requiring only one live feed.That saving on cable is good so will now go the 10mm route.
I will install the IP isolator in zone 2 so 2m from edge of TUB as I have an RCD.On the CU this will be the only item on the RCD so ,so will go directly into that so no need for an MCB.The existing CU only has a main switch and RCBO's so i only have one neutral bar as its not a 17th edition one.

Sorry a little confused there, but is there overload protection there if your not using an MCB

 

[Engineer54]

I take it this is spa/jacuzzi manufactured in the USA/Canada?? If so, that's the reason for inclusion of the rod, it's for there domestic TT system, they prefer to then add a rod to these Spas, if the house Ra is over the recommended NEC codes 20 ohms, which most are...

Had plenty of these things on projects over the years and are pretty common over here too. Never once have i seen or used a rod on any. Use the TN-S earth, it's going to be more than adequate, nothing to stop you roding as well if you wish. If the supply to this unit requires 60A then you really do need to be running in a 10mm cable.

Some of these units are equipped for main water service, others are not, some have the facility for water heating from a central heating/remote boiler system, via a remote heat exchanger and again some don't.

Just my opinion of course, your going to be the designer/installer at the end of the day.... lol!!!

 

[malcolmsanford]

E54 yes agree that in the States almost all outside equipment tend to recommend Rods, but in fairness most do in the UK as well for spas/jacuzzi as they are worried about potential difference over the ground and all that water. They do recommend more often than not to tie the installation down to a rod.

 

[Engineer54]

Never heard of that one Malcolm, but haven't been around in the UK for sometime now for any length of time. I know that the Spa's manufactured in Europe, don't come with spikes, and no mention of them in there literature either, apart from connection arrangements for there equipment, for TT systems.

I can see your point, but then the Spa installation would need it's own RCD device protection. Many do incorporate them but there are also those that don't!!!

 

[Roger]

Sorry a little confused there, but is there overload protection there if your not using an MCB

Sorry brain fade,trying to get a device which will do 60amp.All RCBO's and MCB I have found only go up to 50amp max so i was thinking about a 63amp device and have a few 63amp RCD spare.
I can use a 2 pole RCBO rated at 63amp which will obviously give me the required protection and fit the CU.
10mm armoured £3.50/m (not bad i thought)

 

[ste mac]

Does it definatley need a 60A feed? My hot tub runs on 4mm SWA and a 32A MCB. It is a canadian hot tub. In the instruction manual it states -

"Americas 60Hz - 240v. Circuit breaker - 50A. Number of wires - 4."

"Europe 50Hz - 230v. Circuit breaker - 32A. Number of wires - 3."

This seems to tally with the info on Cheshire hot tubs website:

Electrical Supply
You will need to install an electrical supply. This needs to be 6mm 3 core armoured cable with a 5-6 metre tail which terminates at the side of the spa. It needs to have a 32 amp c rated trip m.c.b . and a 30m R.C.D. We recommend that all electrical work is carried out by a qualified electrician. If the spa is to be sited indoors bathroom regulations apply.

 

[Roger]

Looked again and it does recommend a 60 amp supply and the use of 10mm copper wire,However another page says max current draw will be 46amps.Think i will go with my 50amp RCBO and 10mm SWA.Will use the TN-S earth,although have come across some posts where people have found that a spike is necessary as people have had small shocks.
thanks