immersion heater wall switch.

[deadshort]

I have also seen all three in various places burnt out.

Would that be due to you're wiring method? i.e. 32a OPD protecting the wiring

Regards,

DS

 

[EFLImpudence]

No.

It's difficult to see how the omission of an FCU or plug could cause them to overheat.

 

[JohnW2]

I have also seen all three in various places burnt out.

Would that be due to you're wiring method? i.e. 32a OPD protecting the wiring

The rating of the OPD is surely irrelevant? An accessory will only 'burn out' if an excessive current flows through it (or if the termination of conductors within it are not satisfactory) - and, to-all-intents-and-purposes, an immersion cannot create such an 'overload', no matter what OPD is protecting the circuit.

[some 'clever' soul sometimes comes up with the suggestion of a short from the element to its earthed casing part way along the element - but that, of course, would cause an RCD to operate]

Kind Regards, John

 

[bernardgreen]

How many kilowatts is the immersion heater ? If it is 2 kW that it can be on a 13 amp plug. ( good quality one, not a 99p one ).

Having it on a plug or two pole FCU allows it to be fully isolated when it develops an earth leakage fault.

 

[JohnW2]

How many kilowatts is the immersion heater ? If it is 2 kW that it can be on a 13 amp plug. ( good quality one, not a 99p one ).

The vast majority of domestic immersion heaters are 3 kW, aren't they? Although that is theoretically still within the rating of a 13A plug - but, as EFLI has said, that can result in problems.

Having it on a plug or two pole FCU allows it to be fully isolated when it develops an earth leakage fault.

... or (as EFLI has also said), preferably, a two-pole (probably "20 A") switch.

Kind Regards, John

 

[securespark]

I can't find any on the market now, but when I started in this game, there were domestic immersion elements that were on the wrong side of 3kW.

Not talking about electrode boilers...!

 

[Iggifer]

here we go

http://www.onestopbioshop.co.uk/shop/2kw-immersion-heater/

 

[EFLImpudence]

Interesting that they state:

"UK manufactured Incoloy 2kW Immersion Heater which is suitable for wiring into a standard 13a plug socket. We are one of the only few companies in the UK to offer such product.

Please do not mistake this product for a 3kW Immersion Heater which is not suitable for wiring into a normal 13a plug socket."

 

[JohnW2]

here we go ...

I didn't say that 2 kW one's don't exist but, rather, that the vast majority of domestic ones are 3 kW, and I still think that's true.

Even the link you provides implicitly admits that they are very unusual, claiming that they are one of the few sources of 2 kW immersions in the UK!

Kind Regards, John

 

[deadshort]

The rating of the OPD is surely irrelevant? An accessory will only 'burn out' if an excessive current flows through it

WTF ?

DS

 

[JohnW2]

The rating of the OPD is surely irrelevant? An accessory will only 'burn out' if an excessive current flows through it

WTF ?

What's your difficulty with what I wrote - it's surely a statement of the obvious, isn't it? If the nature of the load is such that it cannot result in an ('overload') current greater than, say, 13A, then an accessory which can tolerate 13A without 'burning out' will not burn out, whether the OPD is 13A, 20A, 32A or 50A.

Fault (rather than overload) currents are a different matter - but, provided the Zs of the circuit was low enough for the particular OPD protecting it, the OPD (whatever its rating) would operate in response to a fault.

Kind Regards, John