Immersion heater consumption

[Alan de Enfield]

I have purchased a 'wattometer' (plug it into a socket and it shows watt being 'used').

 

Why does my 1kw Immersion heater show 1198 watts on the wattometer ?

 

(Is it really a 1200w heater element ?)

[Tash and Bex]

Just now, Alan de Enfield said:

I have purchased a 'wattometer' (plug it into a socket and it shows watt being 'used').

 

Why does my 1kw Immersion heater show 1198 watts on the wattometer ?

 

(Is it really a 1200w heater element ?)

I suspect it may be down to the voltage. The meter may well display watts assuming the standard 230v rms is present, do you know if this is the case, there can be huge volt drops on marina wiring!

[nicknorman]

1 minute ago, Alan de Enfield said:

I have purchased a 'wattometer' (plug it into a socket and it shows watt being 'used').

 

Why does my 1kw Immersion heater show 1198 watts on the wattometer ?

 

(Is it really a 1200w heater element ?)

It will depend on the supply voltage. The element will be a more or less fixed resistance (R) and perhaps rated at 220v.

 

Power dissipated by the element is V squared / R. So a 9.5% increase in supply voltage will give a 20% increase on power. Perhaps your supply is 240v?

 

Plus of course there will be a bit of measurement inaccuracy.

[Alan de Enfield]

9 minutes ago, Tash and Bex said:

I suspect it may be down to the voltage. The meter may well display watts assuming the standard 230v rms is present, do you know if this is the case, there can be huge volt drops on marina wiring!

 

9 minutes ago, nicknorman said:

Perhaps your supply is 240v?

 

Good thinking - just measured supply at 247 volts.

[Murflynn]

which would result in a consumption of about 1160 watts for a nominal 1kW heating device.

[Alan de Enfield]

14 minutes ago, Murflynn said:

which would result in a consumption of about 1160 watts for a nominal 1kW heating device.

So - where are my other 38 watts going ? (rhetorical question)

[Tash and Bex]

Just now, Alan de Enfield said:

So - where are my other 38 watts going ? (rhetorical question)

i'm a gonna guess the cabling will consume a bit, and there will be a tolerance in the consumption of the heater of a few percent

 

[ditchcrawler]

Was the Watt meter calibrated?

[Alan de Enfield]

18 minutes ago, ditchcrawler said:

Was the Watt meter calibrated?

WATT !!

 

I'll have to send it to MtB he seems good at getting widgets calibrated

[WotEver]

24 minutes ago, Alan de Enfield said:

WATT !!

 

I'll have to send it to MtB he seems good at getting widgets calibrated

No, just buy two more.

[ditchcrawler]

16 minutes ago, WotEver said:

No, just buy two more.

Old Chinese proverb, Man with working watch always knows time, Man with 2 working watches never knows time