Outdoor Hot Tub Solution Required

[TestPress]

Only found this site recently - excellent forum!

Anyway. I require 3 sockets to be installed on the outside of a house. The 3 sockets will be feeding a hot tub (about 1200 watts), a lawn mower and a pond pump.

Will the following solution be viable?:

A 20amp MCB in the consumer unit.
From the MCB a 12 metre run of 2.5mm cable - the cable would be routed through a wall then down to the outdoor sockets.
The 2.5mm cable would feed the 3 sockets, installed as a radial circuit (each socket would have its own RCD).

Many thanks in advance.

 

[Lectrician]

The price of 4mm is not much more than than 2.5.

I would go for a 4mm radial, on a 32amp RCBO. Fit IP68 double masterseal (MK) sockets, no need for an RCD in each.

The hot tub would be better IMO on it's own circuit. Maybe you could run a 4 core armour, using 2 cores for sockets, and 2 cores for tub (armour as earth).

Look into the hot-tub, just double check it is only 1.2kw. Rare to see them so small, although I have been told they design some to run off a plugtop, so possibly this is one of them.

 

[TestPress]

Thanks.

The hot tub does actually run off a plugtop, although I do like the idea of running it off its own circuit and the other sockets running off their own circuit.

If that is the case, regarding the hot tub, would 2.5mm cable feeding a single RCD protected socket, with a 20amp MCB at the consumer unit be sufficient?

 

[Lectrician]

Yes, should be.

If the tub is on the same route as the sockets, I would look at a 2.5 4core SWA, or 4mm would be even better.....

You dont mention lengths.....I assume not far, as long runs would require a larger cable due to volt drop

 

[TestPress]

From consumer unit to hot tub socket, about 12m, add another 3m from socket to hot tub.

I do like your 4 core armoured option, though due to the fact I already have certain materials available, I think I'll stick with the above option for the tub.

Adding another 2 outdoor sockets (one socket for a lawn mower), on their own way at the consumer unit, I take it the same solution solution as the hot tub would be suitable? e.g. 20A MCB, 2.5mm cable and a RCD protected double socket?

For future projects I would certainly go for your option!

 

[Lectrician]

Yea, sounds fine.

Way the price of an RCD socket up against an RCBO that will fit in your existing consumer though......

Unless you have the sockets already aswell

 

[TestPress]

Lol.

Well what it is, I'm trying to make the best of what I have.

Basically, the house has an old (about 20 years old) consumer unit that takes Stablok MCBs. By chance I was given 2 x 20A Stablok MCBs so I though I'd make the most of them - rather than change the consumer unit.

Obviously, the downfall of all this that for outdoor circuits, (as I only have 20Amp MCBs), is that I am restricted to using 2.5mm cable, and am unable to use RCBOs, so I am forced to use an RCD with each socket.

But I guess I'm still within regulations with what we discussed above, so it can't be too bad?

 

[Lectrician]

You could look at putting 1 or 2 standalone dinrail RCD's into a 4 mod enclosure adjacent to the CU, or somewhere practical. This again may be cheaper than several RCD socket outlets.

Interestingly, thermosetting SWA will carry upto 36amp clipped direct, and PVC SWA Will only carry 28amp.

Most wholsalers sell the smaller sizes (16mm and below) in thermosetting only........

But as you have the 20amp breakers.........




As for complying to the regs, yes, the setup sounds fine........I cant vouch for the installation as a whole though

Make sure you use the correct CW20S glands for the cable - seen many DIY'ers use TRS glands in the past, and forget about the armours.

With any new works, you should upgrade your main equipontential bonding.....search here for that.

Also, be aware, as I am sure you are..............(I waited to the last minute to say it )...........Part P