immersion heater and a shower pump

[SimpleSimon]

I under stand this, what im saying is that you would use a 20 amp db pole switch and the protective devices at the ccu would be 16 amp.
this would also give local isolation, but you would still need to isolate the circuit as you may have a loose wire in the spur.

Can't really count an MCB switch as local isolation IMO unless the DB is within reaching distance of the DB.

 

[Martin Bradley]

So the 20 amp double pole switch would not give local isolation come on, of course it would, what i am saying is that the 20 amp double pole switch would not be fused but would offer local isolation, but for maintenance work the 15/16 amp protective device would give you complete isolation.

 

[tonys]

There's nothing wrong with any of the following methods with regards 3kw Insulated immersion heater elements operated via a thermostat.

20 amp double pole switch backed up by a 16amp mcb/15 amp 3036: this method as been around since I was an apprentice in 1984 and that's the way I was taught.

13amp switched fused spur: used this method many times.

13amp plug top: never used this method myself, but it was not against the 15th or 16th Edition Regs and not against the 17th as far as I'm aware.

Only other thing people can do is ring their scheme Technical Help Line if they can not agree with any of the above but make sure you mention the word Insulated

 

[andyb]

Tony

I read your earlier post regarding insulated water heaters and I am confused by the term insulated in this instance.
Obviously the element is not in contact with the water but the outer sheaving is copper which is in contact with the water. The regs define insulation as a non conductive material, now I know there is a barrier between the conducting part of the element & the outer copper sheath, but I'm not sure that I would class a domestic immersion heater as insulated. Although I'm open to discussion on this.

Also the IEE on site guide states that an immersion heater should be fed from a fused connection BS1363-4 but gives no reg number as a reference.

 

[tonys]

Andy

I'm not that technical to be honest with you mate. I'm going on what I was told by the NICEIC Engineer who pulled me on a PIR just before the 17th came into to force where I had coded a immersion heater (the domestic type) for being on a plug top. So unless someone can show me where the regulations have changed on this, I'm going to stay with what I was told.

How the terminology goes with regards to the insulated material between the inner and outer part of the element, phoning a manufacturer might verify who's right in this instance. The NICEIC don't normally get things wrong imo, but like I said if someone shows me the regulation change I'm happy to accept it.

Andy

Also, what would you say with regards to a kettle element, are they not of the same principle ?

 

[malcolmsanford]

Andy not sure if immersions have changed, as I don't do a lot with them now but everyone I worked on you had to drain the tank before removing the element as they were immersed in the water. To be honest I tend to go with pushrod on this and think they are covered under Reg 554.3. and therefore not to be connected via a BS 1363 socket and plug.

As I don't work on them enough and someone definately told me they do not some under these set of Regs I certainly wouldn't argue with them.

 

[tonys]

Immersion heater

Water heating by electricity is usually done by an immersion heater mounted in the top of the hot water cylinder. The heater contains an insulated electric resistance heater and a temperature sensor. Domestic immersion heaters (usually rated at 3 kilowatts in the UK) run on the normal domestic electricity supply. Electric shower and tankless heater also use a immersion heater shielded or naked which is turned on by the water passing and turned off when the tap is closed. A group of heater working each one or together provide different heating levels. Electric showers and tankless heaters usually have since 3kilowatts to 7.5kilowatts according the voltage supply. Industrial immersion heaters (such as those used in electric steam boilers) may be rated at 100 kilowatts, or more, and run on a three-phase supply. 11
[edit] Electrode heater

With an electrode heater, there is no wire-wound resistance and the liquid itself acts as the resistance. This has potential hazards so the regulations governing electrode heaters are strict.http://en.wikipedia.org/wiki/Electric_heating#cite_note-0

 

[andyb]

Good points Tony, as I said I'm not clear myself.
The IEE in their on site guide usually include a reference to the regs,
In this case they do not.

 

[malcolmsanford]

Wikipedia is a wonderful tool

 

[tonys]

Andy

Ill will always trust the advice of an NICEIC Engineer over the majority of members on here. IQ is another one who I trust, hes another qualified Engineer.

 

[tonys]

Wikipedia is a wonderful tool

So you still not agreeing with me then Malc, you not that confident in a NICEIC Approved Contractor QS then lol

 

[malcolmsanford]

No mate you copied and pasted that to perfection, we now know what an immersion heater is, what I would like to know is if it's covered by regulations 544.3 as I think it is, but as I said I can't remember the last time I did an immersion and certainly not in the last 5 years.

 

[Deleted member 26818]

Don't quite see the problem here.
Immersion heaters have been required to be permanently connected via a DP switch for about 30 years.

 

[tonys]

Don't quite see the problem here.
Immersion heaters have been required to be permanently connected via a DP switch for about 30 years.

We are talking about a plug top and given it disconnects both live and neutral conductors at the same time, then it is also acceptable imo

 

[malcolmsanford]

Spin yes that or a FCU.

What the discussion is about that Pushrod seems to think that immersion heaters are covered by Regs 554.3 and in that set of regs 554.3.3 states that an immersion heater can not be connectedvia a plug and socket. I tend to agree with him, but as I've stated I don't normally work with immersions and when I do it is always connected up with either a 20amp double pole Switch or a Double pole 13amp FCU, and never thought of doing them by a plug or socket.

Tonys seems to think that an immersion does not come under these regs and so connecting via a socket and plug is ok.

Now I don't know this part of the regs well enough to say aye or nay, hence the discussion, which is why I think most of us use the forum as it opens up a good debate.