Fused spur from an immersion switch?

[Swicade]

Cant think of any smegulation against upgradeing to 20A mcb (cable distance permiting) and slinging 2 heating appliances on the one (what used to be) dedicated supply.

While we're at it may aswell start wiring Night store heater supplies the same way....may save abit of cable/ time/ money .....rumour has it 'Dedicated circuit' has reserved the plot next door to 'Common sense'.

TBH wouldn't do it meself.... people who still wire immersion heaters off a RFC annoy me.... but each to thier own, as long as it's quick/easy/good earner then alls good.

 

[Deleted member 9648]

Wirepuller ... this wouldn't comply regarding the 2way switch method as it would fall foul of 554.3.3 unless you were to have a double pole switch also which you failed to make clear in your suggestion.

Agree..assumed it would be obvious...but should have made that clear.
I have used this method before,once when a regular client had done a bathroom and had UFH fitted by the tiler who had left the tail next to the IH FCU just assuming we would feed off that. There was no way of getting another supply to to the point without disruption to his new bathroom, so I fiitted the 20a 2way switch to the IH supply radial and then to a 20a DP switch for the IH and an FCU for the floor heating..both applinces DP switched,the 2w was labelled as a changover sw only..the 16a mcb remained the same and before anyone asks,yes it was RCD protected. As far as I'm concerned this remained a dedicated circuit as only one appliance could be in operation at once.

For what it's worth I also think the IH should remain a dedicated radial,partly because it's recommended in 7671...and partly because it's traditional and therefore expected,and partly because it makes sense.
I think the 20a upgrade and supplying the heater from the IH would be a very last resort if there was no other way.
But the regs are not statutory...and if there was no other practical way of feeding the heater there is no reason why it couldnt be done cable ratings etc permitting...as depending on installation methods there may be as much as twice the capacity on a 2.5mm as the 3kw load,and the OP stated 5a FCU which must be a max of 1kw....or possibly much less. That was all I was attempting to get across to KAS1...who never once provided any valid reasoning for his stand beyond a rant,which is inclined to cause digging in and trench warfare rather han a sensible discussion.

 

[KAS1]

I'm only trying to get some of the so called sparks on hear to to a "good job" if the customer can't afford it then walk away, don't let some people, talk you into short cuts, you know it makes sense to do the right thing ie good workmanship after all that's one of the things this industry used to pride itself on. As for running another curcuit of an immerstion heater curcuit in my book that's a short cut and a bodge (maybe a temp) don't do it, we can all work the regs to suit ourselves at times but lets keep things to a standard. Next they'll be saying it's ok to run a cable from your IH out to a spur fused down for your shed lights or whatever.

 

[Rockingit]

I'm not going to get embroiled in some silly biggest willy contest in the boys toilets, and as such I've not read the entire thread.

Circuits, however they are (safely) devised, are there to feed equipment. What we call those circuits afterwards is almost irrelevant. So if someone has got spare 'capacity' on an existing circuit to feed more equipment (safely), then that's fine by me as far as principles are concerned. Practicalities might suggest doing something else, of course.

 

[Octopus]

I'm not taking sides here but lets say its added to the immersion circuit - then an inspection is done - my bet is on that its a C2 and fail for a shared circuit!!

 

[KAS1]

Sounds about right to me lol

I'm not taking sides here but lets say its added to the immersion circuit - then an inspection is done - my bet is on that its a C2 and fail for a shared circuit!!

 

[HandySparks]

I'm not taking sides here but lets say its added to the immersion circuit - then an inspection is done - my bet is on that its a C2 and fail for a shared circuit!!

I'm not saying it's a desirable situation, but providing the current carrying capacity of the cable is sufficient under all conditions of use, I wouldn't regard it as potentially dangerous and would therefore give it a C3.

 

[Octopus]

I'm not saying it's a desirable situation, but providing the current carrying capacity of the cable is sufficient under all conditions of use, I wouldn't regard it as potentially dangerous and would therefore give it a C3.

Which means you would perfer it not to be like that or simply doesn't comply??

 

[Deleted member 9648]

In order to code it at all it would have to contravene a regulation.....if you fella's want to point me in the direction of the appropriate regulation I'll stand corrected.

 

[Geoffsd]

It's quite difficult to take this seriously but can a 2.5mm 20A radial circuit not supply items totalling 20A?
(Could even be 25A I suppose)

One solution would be to go to the CU and under where it says 'Immersion' write 'and heater'.

 

[Octopus]

In order to code it at all it would have to contravene a regulation.....if you fella's want to point me in the direction of the appropriate regulation I'll stand corrected.

Which is my point.

The regulations aren't clear and need to be clearer to sort out all this ambigiuty.

 

[KAS1]

I love this thread, it's all down to good workmanship that's what some are not even considering, lol

 

[MDJ]

This is another one of these discussions where no one is right, like the shower situation with the double pole switches we have been chatting about, there is no reg in this or that, although it is not wrong here to come off the 2.5 feeding the IH, you wouldn't want to tell your boss what you did in case he sacked you haha

 

[Octopus]

I love this thread, it's all down to good workmanship that's what some are not even considering, lol

I have to disagree with you.

Regulations and good workmanship go hand in hand.

So you are suggesting that as long as the installation has good workmanship then the regs don't apply??

 

[Deleted member 9648]

Need to put some power to a small wall mounted electric heater that takes will take it's power from a 5 amp fused switch outlet. It's in a flat and the least disruptive way I can see of doing this is by running a 2.5mm T&E cable from the immersion switch to the 5A switch fused spur then connecting the heater to this. The immersion is on its own 16A radial. I can't see anything that may not comply with regs on this but a colleague thinks different. Anyone provide clarification on this?

thanks

I love this thread, it's all down to good workmanship that's what some are not even considering, lol

I'll refer you to the OP's original question...which is asking if it's possible to do within the regs,which whether you and I like it or not,it is.

 

[MDJ]

Theres no reg saying theres a problem with the OPs question that I can find.

 

[KAS1]

So it might be, but why encourage someone who doesn't really know what he's doing, to commit bad practice, this is the a sort of question if someone on site asked me I would think Oh my God where has he learned his trade and send he back to the agency lol

I'll refer you to the OP's original question...which is asking if it's possible to do within the regs,which whether you and I like it or not,it is.

 

[Deleted member 9648]

So it might be, but why encourage someone who doesn't really know what he's doing, to commit bad practice, this is the a sort of question if someone on site asked me I would think Oh my God where has he learned his trade and send he back to the agency lol

I'd have a lot more respect for your opinions if you explained your reasoning...might even be persuaded.
A similar argument blew up over neutrals in switches....while the detractors wrung their hands in horror they never actually came up with a valid reason why neutrals in switches were bad practice.

 

[MDJ]

Give it up KAS1, there is no reg saying a Bathroom heater cannot be taken off the same 2.5mm2 T&E as the immersion, whether it is considered bad practise by some, me included, however it is not against regs and no problem, so the answer to the OPs question "is it is okay to do this", as you have no other supply around to feed the heater? "I would suggest upgrading the MCB to 20 amp and then it should cope with both loads".

 

[Geoffsd]

It's nothing to do with bad practice.

It's a perfectly valid and acceptable electrical circuit.

Is any one saying that when a cooker is replaced with an oven and a hob it is not acceptable to have both on the 'dedicated' circuit?



In reply to the earlier post likening this to storage heaters, I would point out that two 3kW heaters makes 26A.
Therefore the comparison is invalid.
With 4mm and 32A it would be fine.

Stating the bleedin' obvious but unfortunately it seems necessary.

 

[Darkwood]

I see alot of deep routed practices turning into a blinkered veiw on what is allowed, bad practice or acceptable.. what is lacking here is qouted regulations which say you can't put more than one point on a final circuit and reg's do exist to ensure that if this is done that your circuit still complies with

Chapter 43 for overcurrent protection
Section 537 for isolation and switching
Chapter 52 re' CCC of conductors

Check this with reg 314.3

What has been taken out of context is the term' dedicated circuit ... we are talking domestic here not your hospital install in such that the requirements of reg 314.1 (i) and (ii) really wouldn't be a big concern if circuit is clearly marked and isolation is suitable that in the event of a fault the offending load can be safely isolated.

Dont just throw you bat out spouting how very dare or poor / bad practice without showing relevent regulation to reinforce your argument, the O/P has asked a question regarding an existing install if he has limitations i.e. Cost or difficulty in wiring alternative methods he can suggest what has been put forward in this thread as long as he complies to 314.3, the customer will be made aware of the pro's and cons and also an update of circuit designation will be made.


His test results and submitted test sheet will at most just note the addition and limitations to using other methods and this is all that is needed as it will comply with regulations in every aspect be safe and correctly protected.


Having said this you need to not confuse this debate on guidelines you read regarding having seperate circuits for imm' heaters as these are recommendation for new installs and yes if rewiring in full or new build its good practice to have a dedicated supply to I/H but i stress it is neither disallowed or bad practice to do what the O/P intends as long as he complies to the requirements of section 314 (314.3 in particular).....

I do commercial and industrial and its common to find a supply that may have a change over switch to alternate it to two different machines and as long as it dosn't contrevene regulation there is nothing wrong with the way its been done, the fact is its a rarity in domestic and just because its not often seen dosn't mean its not allowed or bad practice or hells gonna swallow you up just try to realise just because you have never done it dosn't mean you are right to say it poor workmanship it just means your still in-experienced and learning your trade.

Hope this draws a line of some sort.

 

[KAS1]

I don't understand why he would even want to wire his wall heater this way, why didn't he just spur it of the ring(fused down of course). I think he was looking at a easy way instead of lifting a floorboard or two. Making a fast buck as they say. Whatever you think wirepuller it's bad practice to do what you seem to think is ok. Perhaps he could fix a label at his new spur stating that the load from this spur must not exceed 5amps in the correct size lettering of course perhaps red lettering on a white background at least 300mm x 150mm size should do the trick, oh as someone else said not to forget to label the breaker at the CU as well, something on the lines of Immersion Heater plus little 5amp fan heater opposite (wall mounted) That should do the trick lol

 

[HappyHippyDad]

For ****s sake dedicated circuits don't count for anything anymore are you thick

I've really tried to stay polite with this kids replies, but he is offering absolutely nothing but insults to this forum. Perhaps if he had been on here for a while and built up a reputation I could hack it a little more, but he hasn't. He's just a kid trying to show off and I hope the moderators have a bit of a word with him.

 

[Guest55]

For God's sake I rest my case this place has a lot of diyers

not good at making friends round here are you ?
clearly our forums lowly knowledge and skill doesnt meet your expectations so why dont you jog on to the screwfix forum , you'll fit in perfectly there.

 

[Guest55]

So it might be, but why encourage someone who doesn't really know what he's doing, to commit bad practice, this is the a sort of question if someone on site asked me I would think Oh my God where has he learned his trade and send he back to the agency lol

so 5 pages of debate later you concede theres nothing against doing it in bs7671.
lol . congrats on looking a right tool.