15Amp immersion plug

[markc123]

i like the term modern immersion heater lol immersion heaters, sadly, are starting to become a thing of the past.

The immersion heater in question, what kW isit? Most are 3kW and wired on 13A SFCU.

3000W is over 13A ... just. But it was ALWAYS regardless of what the 'everything exactly by the book' brigade say fine to put on a 13A SFCU.

What kW is the immersion heater in question? Obviouslly if we're talking way over then you're right to assume that it can't go on a 13A fuse.

 

[Engineer54]

As I only work on older installations can someone tell me how modern immersion heaters are wired? I assume it's via a flex outlet switched through a 20A isolating switch?some older immersion heaters are over 3kW which presumably could be wired the same.I'm reluctant to put it on a 13A fused spur or plug and socket as I don't think that would comply if it was over 13A

So what KW rating does it state on the element?? Most domestic immersion heaters going back to the early 50's, were and still are, based around thermostatically controlled 3KW elements. No need for a 13A fuse, (fcu) a 16A OCPD, and a local 20A switch is all you require on a dedicated circuit!!

 

[Engineer54]

3000W is over 13A ... just.

Only if you use, the very much make believe nominal 230V!! If you use what is the ''Real'' nominal 240V, it'll be closer to 12.5A!!

Didn't realise people actually believed in the make believe harmonised nominal 230 Volts!! lol!!

 

[markc123]

Only if you use, the very much make believe nominal 230V!! If you use what is the ''Real'' nominal 240V, it'll be closer to 12.5A!!

Didn't realise people actually believed in the make believe harmonised nominal 230 Volts!! lol!!

Nah i do realise it's give or take -10/+6 % on 230V ....i've probably got that the wrong way round, and im sure you'll let me know if have E54 lol

Just standard dogs dinner practice to base everything round 230 these days

 

[markc123]

and ill shock and disgust you here E54 lol...but thinking about it, can't remember last time i used a cable calc @ 240 lol! 230V has been zapped into most of us here in the UK now ... i bet you're glad you're out of the harmonised(*hypnotised) life of been a sparky here now.

 

[Tommy T]

I'm with Dickie Burns up top, 20A, and shouldn't be on a plug and socket.

 

[snowhead]

not in bathroom. shrouded pins?i don't think that's really the issue.it's never removed.it's been failed by someone who thinks an unfused plug deserves a code 2.I don't think it does so what can i do to get the customer a pass on his inspection?

Irrelevant
It COULD be removed.

Remove the plug and socket.

 

[westmac]

Only if you use, the very much make believe nominal 230V!! If you use what is the ''Real'' nominal 240V, it'll be closer to 12.5A!!

Didn't realise people actually believed in the make believe harmonised nominal 230 Volts!! lol!!

How exactly would a higher voltage reduce the power consumption of a resistive load such as a heating element? The power rating is based on a nominal voltage, the resistance (no impedance involved as the load is purely resistive) is constant so a higher voltage will result in a higher current and so a higher power output from the heater.

 

[Octopus]

As I only work on older installations can someone tell me how modern immersion heaters are wired? I assume it's via a flex outlet switched through a 20A isolating switch?some older immersion heaters are over 3kW which presumably could be wired the same.I'm reluctant to put it on a 13A fused spur or plug and socket as I don't think that would comply if it was over 13A

Did you not read post #2?

 

[Dcf]

A 15a plug and socket at the tank was a standard method of connection back in the day.
i agree with e54 that the amount of brass in one of the old 15a plugs can take a lot more than 15a
which you will never be near on an immersion btw.
If it troubles you fit a 20a dp switch not a 13a.
the switch will burn out eventually due to being run at full tilt for most of its life
how many 15a plugs have I seen burnt out .... Eh none.
how many 13a plugs and switches doing immersions ....loads

 

[electrician4u]

i don't think the size of the cable is much of an indicator of the load! the last time i tested similar immersion heaters they were drawing just short of 3.2kW

 

[electrician4u]

I'm still after advice on the paperwork i would supply to say it's now safe if someone else did the initial test

 

[telectrix]

Mewic. you will have altered the circuit, so that's what you need .

 

[HandySparks]

How exactly would a higher voltage reduce the power consumption of a resistive load such as a heating element? The power rating is based on a nominal voltage, the resistance (no impedance involved as the load is purely resistive) is constant so a higher voltage will result in a higher current and so a higher power output from the heater.

Quite. It's only 'constant power' equipment (typically with switched mode power supplies) that take reduced current at higher supply voltages.

Here's the spec for a typical range of immersion heaters.

3kW @ 240V (2.8kW @ 230V).

So 12.5A at 240V and 12.17A at 230V. It doesn't work out exactly as constant resistance but that's just because the power figures are stated to the nearest 100W.

http://www.heatraesadia.com/docs/Immersion_Heaters_-_Issue_4.pdf


Edit: However, I think E54 was just saying that you need to check the spec, and not just assume that the quoted '3kW' is at 230V (as electrician4u seemed to be implying).

Perhaps I should just shut up before I get into deeper water!

 

[Engineer54]

How exactly would a higher voltage reduce the power consumption of a resistive load such as a heating element? The power rating is based on a nominal voltage, the resistance (no impedance involved as the load is purely resistive) is constant so a higher voltage will result in a higher current and so a higher power output from the heater.

I just did a quick bit of mental arithmetic as in 3000 div 230 and then 240!! hey presto 13 and 12.5!! ...lol!! Youre problem is, that you're using a make believe nominal voltage, rather than the real voltage!!