3-way immmersion heater electrical connection?

[Maurice]

We have a hot-water cylinder with 2 immersion heaters.

(2 heaters ecause we have no other means of heating bath/shower volumes of water, and need a reserve heater in case of heater failure.)

At the moment each heater is separately connected, with the inherent danger that someone will try to switch BOTH on, with a consequent fuse overload.

Is there such a mains unit that would provide for 2 inputs, and offer a 3- way choice of:

(1) Heater 1 or (2) Heater 2 or (3) Neither ??

[Tufnell Park]

Most electrical accessory manufacturers produce a dual immersion heater switch that should satisfy your requirements.

eg MK K5207WHI

[spuorgelgoog]

As well as the manual bath/shower switch MK K5207WHI mentioned by Tuffnell Park below, economy 7 controllers like

will do the bottom heater on timed (which can be adjusted using tappets behind the clockface) and the top heater on boost, but not simultaneously.

Owain

[Brian Gaff]

Many systems use two heaters in one tank. Can the circuit be upgraded? Its not going to blow up after all. Brian

[Brian Gaff]

In any case we used to have toggle switches with centre off, where up was 1 down was the other and centre, as I said was off. That old company called Bulgin used to do them with very high current ratings. Wonderful bits of kit. Brian

[tabbypurr]

I presume that if you ran them in series most of the time they'd last a lot better. Series or not could be controlled by a 2nd stat.

NT

[ARW]

Thanks for doing my research for me:-) Tonight's job when I got in was to have a look for one of those.

Thanks

[Cynic]

A good old fashioned 16A socket after the on/off switch and 16A plugs on each heater?

[Dave Liquorice]

So "seprately connected" is to the far end of the same bit of 2.5 mm immersion heater radial wiring rather than the far end of two seperate 2.5 mm radials?

The former is a bit of a bodge IMHO, prospective maximum load exceeds that capacity of the fixed wiring. If it really is that I'd run in another 2.5 mm radial if there is a spare way in the CU for it or upgrade the existing radial to 4 (6?) mm and change the MCB (presuambly or are you still on wired fuses at the CU?).

[spuorgelgoog]

15A would be more than adequate, especially if of a good brand (MK until the 1980s) and a lot neater than a 16A ceeform. Or maybe you meant 15A?

Council houses near me all had the immersion on an MK 15A socket.

Owain

[Robin]

or a second run of 2.5mm with both connected to /one/ (uprated) MCB or fuse? I know some deprecate it but 2.5mm is cheaper than 4mm and may be easier to fit.

[Maurice]

The main board has only a 16A breaker - not enough for 2 immersions on at same time.

Ideally that would be updated to a higher rating, but that's a much bigger job than I'm looking for...

Elsewhere I've been pointed at these:

- which would seem to fit the bill.

Regards,