double element immersion heater wiring

[lauriehurman]

Hi Guys
I came across this immersion heater today. Can anyone point me towards a wiring diagram?
top mounted elements, two elements, one long one shorter, only one thermostat, two cables incoming, separate switched elements.
The bit that's got me puzzled is that one of the neutrals has been cut off and the longer element appears not to have two terminals.

Thanks
Laurie

 

[ban-all-sheds]

 

[Iggifer]

The bit that's got me puzzled is that one of the neutrals has been cut off and the longer element appears not to have two terminals

As BAS says, we need pictures, and clearly it can't work without a Neutral

 

[JohnW2]

The bit that's got me puzzled is that one of the neutrals has been cut off and the longer element appears not to have two terminals.

If that's all true, it clearly can't be an element. As everyone has said, we need pictures.

Kind Regards, John

 

[EFLImpudence]

Found this on Google - can't find the associated text.

I suppose the OP's could have both Ls combined.



Apart from that - I have never come across one of these.
As it is - how is it supposed to be switched?
Is a contactor the only way?

 

[JohnW2]

Found this on Google - can't find the associated text. I suppose the OP's could have both Ls combined. Apart from that - I have never come across one of these. As it is - how is it supposed to be switched? Is a contactor the only way?

Very interesting/odd. However, I thought (maybe incorrectly!) that the OP was describing two physically separate elements - which makes even less sense in terms of what he said. We need pictures! 'Dual element' immersions are, of course, readily available, but I've never used one or seen how they are 'arranged', wiring-wise. Sounds as if some more Googling is needed!

Kind Regards, John

 

[JohnD]

appears to be incorrectly, switched neutral.

 

[riveralt]

'Dual element' immersions are, of course, readily available, but I've never used one or seen how they are 'arranged', wiring-wise.

I thought you had a dual element arrangement on your tank?
Although I think you said yours was a top and bottom arrangement rather than both at the top - surely they will be wired the same.
I assume that each will have its own circuit.

 

[JohnW2]

I thought you had a dual element arrangement on your tank? Although I think you said yours was a top and bottom arrangement rather than both at the top - surely they will be wired the same. I assume that each will have its own circuit.

Good memory! Not a 'dual element immersion' - I have two totally separate immersion heaters - one physically at the top (top entry) and one near the bottom (side entry), each with totally separate circuits and switching. Both have neutrals

Kind Regards, John

 

[RF Lighting]

Normally a dual element immersion heater is run through a bath/sink 20A two way selector switch, with the stat switching the neutral.

The one in the picture above is probably wired incorrectly.

 

[lauriehurman]

Ahhhh ... that's interesting. This set-up had a double pole switch and a bath/sink selector.
It was wired so that the double pole switched the bath and the bath/sink switched the neutral from the double pole.

I changed it so that it didn't switch the neutral but then couldn't see what to do on the top of the cylinder.

Laurie

Normally a dual element immersion heater is run through a bath/sink 20A two way selector switch, with the stat switching the neutral.

The one in the picture above is probably wired incorrectly.

 

[bernardgreen]

Provided the controlling switches do not permit a live to be present at the heater without the neutral also being present then there is nothing wrong or dangerous in switching the neutral to select which element or elements are powered. Double pole switching is necessary in this case.

In the event of a heater fault connecting the element to the earthed casing ( and where there is no RCD protection ) the heater between the live terminal and the fault would be powered by live and earth so the thermostat ( and safety cut out if fitted ) have to be in the live feed to ensure power is removed if the tank is over heating.