Shed and jacuzzi advice

[brynmor steel]

Hi, I’ve been asked to install lighting and 3 sockets (one of which is for a fridge) in a wooden shed. Due to location of consumer unit the only feesable option is to use the feed from the Jacuzzi which is on the non RCD side of the CU using a 40A MCB with 10mm Twin & Earth cable and own isolator switch.

Total length of cable would be 25 meter’s, 19m indoors and 6m outdoors leading to the shed (not buried) to mini CU with RCD protection

The jacuzzi is 6Kw and fridge 2Kw so 40A mcb will handle load and should be most used at anyone time.

My question is, if I extend the 10mm t & e that inside the house with 6m of 10mm SWA outside the house does it alter my cable calculations as they have different reference methods?

 

[telectrix]

calculate based on the worst case. what ref. method is the existing?

 

[brynmor steel]

looking at the build, which is relatively new, the size of cable and the worst case scenario of the Jacuzzi enclosed in conduit in thermally insulated walls as other methods e.g. show a 6mm cable size is suitable
The SWA will have to be clipped to or under decking which is above ground by a couple of foot

 

[Baker1988]

A 6mm cable might be suitable for the load but im pretty sure it wont wont the current carrying capacity for a 40A mcb once derating factors have been taken into account. Also i was always under the impression that a jacuzzi needed rcd protection as most manufactures recommend als if you are putting sockets for genaral use in the shed these will also need to be rcd protected.

 

[telectrix]

a lot of jacuzzis come with an integral RCD. ours has a 10mA RCD moulded plug on it's LV cable.

 

[Octopus]

out of interest, where do you plan to "join" the cables?

 

[telectrix]

out of interest, where do you plan to "join" the cables?

Vince & Tony?

 

[Squid]

a lot of jacuzzis come with an integral RCD. ours has a 10mA RCD moulded plug on it's LV cable.

Do you have pampas grass in the front garden by any chance?

 

[telectrix]

Do you have pampas grass in the front garden by any chance?

nope, just nettles and dendelions.

 

[Squid]

nope, just nettles and dendelions.

You must be a well off scouser as at least you have a front garden......... ;o))))))))

 

[telectrix]

it's round the back that 'er indoors likes to chill.

 

[brynmor steel]

The CU in the shed will have RCD protection and the Jacuzzi Isolator has built in RCD protection.
I haven’t decided on the connection yet tbh, either at the isolator or extend the cable slightly before the isolator so the Jacuzzi is a spur.