15Amp immersion plug

[electrician4u]

have a customer who's just had a EICR done.has told me he's got a C2 on his immersion heater because it's an unfused 15A plug and socket.Although it's seperately fused in the consumer unit and switched locally, how can that possibly be a C2? he's asked me to remedy it.any suggestions?

 

[Octopus]

Go and fit a 20A isolation switch. As you say its on its own circuit, so what else could you do?

 

[snowhead]

Does the 15amp plug have shrouded pins?

Where is the plug / socket in relation to the Bathroom Zones?

The solution is obvious.

 

[electrician4u]

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?

 

[Steve_P]

This would be too easy..... Please give more information is, I think, the correct reply to this.

Seriously though, without more info it's impossible to say why it's been given a C2. The solution (if there is in fact one to solve) as the others rightly say is quite straight forward though.

 

[Octopus]

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?

Simple. get the customer to email the sparky who did the C2/inspection and ask him to detail the BS7671 regulation that he's refering to. if he can't then he should re-issue the cert with a satisfactory.

 

[electrician4u]

just to add, and in general, if you are required to do remedial work to sort out problems after an EICR and you don't agree with the codes, what paperwork can you provide to the customer to verify that the installation is safe?and even when you do agree with the codes and remedy the faults, what paperwork do you provide?

 

[Steve_P]

Sounds like a plan to me. Or, bearing in mind it's on its own circuit, change the 15A unfused plug (how is a 15A plug unfused? Ahh well...) for a fused one, charge the customer £2500 and go on holiday. Thinking about that, Murdoch's answer is better than mine.

 

[Marvo]

The BS546 15A plugs are unfused. We use them as standard plugs, known as SANS164 locally.

 

[electrician4u]

I've not found anything in the regs about this.If anyone could help, it would be most appreciated

 

[electrician4u]

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

 

[shanky887614]

I've not found anything in the regs about this.If anyone could help, it would be most appreciated

Change mcb, change plug for fused or put fcu before socket.

(Surely you can tell easily if its over 3kw as 3kw is around 13amps, in other words if it was over it would be wired in 2.5+)

 

[Richard Burns]

Many immersion heaters are wired with 13A SFCUs, however the 20A switch is probably better overall, but no problem in using the FCU.

I can't remember why, I think it was something to do with high current through a friction connection, but it is recommended that plug and socket connections are not used for immersion heaters, they should be hard wired.

 

[Engineer54]

Many immersion heaters are wired with 13A SFCUs, however the 20A switch is probably better overall, but no problem in using the FCU.

I can't remember why, I think it was something to do with high current through a friction connection, but it is recommended that plug and socket connections are not used for immersion heaters, they should be hard wired.

If you compare the old BS546 15A plug/socket with the likes of the American flimsy almost paper thin plug top pins on their standard 15A and 20A plugs and sockets, ...that old BS 15A should easily be capable of 30A. ...lol!!

There was at least one manufacturer if not more, that did provide fused 15A plug tops. Around about the same time as the then new, BS 1363 13A fused plugs become the standard for all new installs.

 

[electrician4u]

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

 

[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!!

 

[sparkie141]

I would agree with what Murdoch said - Get customer to contact electrician and have him quote BS7671 Reg which is contravened by such an arrangement.
Sounds like a typical EICR comment from a sparkie that comes across something he doesn't normally see then deems it C2 - potentially dangerous, urgent remedial action required!!
Gives us all a bad name, just because it is not how you would do it or what is seen regularly does not necessarily make it potentially dangerous.
I have seen such an arrangement a few times on older installations: 15/16A Radial circuit to 20A DP w/neon "WATER HEATER" switch in kitchen or utility then off to HWC cupboard terminating in a 15A socket with final connection made via 15A plug top and HR flex to immersion heater.
I really don't see a problem with this unless there is evidence of heat damage to connections, installation is in a bathroom (OP indicates this is not the case), the plug is getting used as the method of functional switching or all other sockets in the house are also 15A and the immersion socket is not RCD protected and may reasonably be expected to supply equipment outdoors :wink_smile:
It's not a method I would choose personally but subject to above I can't see the problem. I like final connection via 20A DP switch with flex outlet for 3Kw 240V immersion - 13A FCUs can overheat and burn out when used on constantly used immersion heaters e.g. E7 arrangements.

 

[FAA Greenie]

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

All you need to do is provide the customer with an invoice detailing the work that you have carried out to rectify the work. They then need to staple that invoice to the original EICR.

If the work warrants a cert, that covers it too

 

[westmac]

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!!

"Your problem is" that you're forgetting which part of the power calculation in this instance is constant. The resistance, apart from a slight variation through increased conductor/element temperature is the constant. The power is not constant at all.

If you introduce a greater potential difference across this fixed resistance you get an increased flow of current, with increased current you get a hotter element as well as a higher power consumption.

This is electricity 101.

 

[electrician4u]

All you need to do is provide the customer with an invoice detailing the work that you have carried out to rectify the work. They then need to staple that invoice to the original EICR.

If the work warrants a cert, that covers it too

ok, thanks. so the fact that on the report the installation is rated as unsatisfactory is not a problem as long as the invoice states that the faults are now resolved?

 

[electrician4u]

I think all the calculations going on have veered from the initial question of whether a 15A plug and socket need to be changed and warrent a c2.what about the rule that if it previously complied, it's not necessarily unsafe.and on that subject, unless you've been an electrician since the first edition, how would you know if something was permitted before?

 

[Deleted member 9648]

554.3.3 prohibits the use of a plug and socket to connect water heaters having immersed and uninsulated elements. This often causes confusion as some take this reg to apply to normal domestic elements. It applies only to a type of element I have never come across.
It is possible that the C2 has been applied based on this reg.

 

[Rockingit]

Deleted

 

[Geoffsd]

I think all the calculations going on have veered from the initial question of whether a 15A plug and socket need to be changed and warrent a c2.what about the rule that if it previously complied, it's not necessarily unsafe.and on that subject, unless you've been an electrician since the first edition, how would you know if something was permitted before?

May I ask what 15A plugs are for?

 

[Octopus]

May I ask what 15A plugs are for?

Old installations

 

[Geoffsd]

So, not compliant with latest regs. but still safe - C3?