Immersion heater: thinking of doing away with it.

[Roger Mills]

You are of course joking! What sort of shower flow rate can you get with

3 or 4 kW? Likely to be not much more than a dribble!

[ARW]

What the f*ck are you talking about?

[John Rumm]

In which case just add a secondary CU for the shower.

[ARW]

Thats a new one for me.

[Roger Mills]

Probably before your time!

The Wylex 6-way CU which I fitted in the 1980's had a notice saying that all the slots were limited to 30A except for the one nearest the on/off switch - which could take 40+A (I forget the exact rating).

I'm still using the CU, but the cartridge fuses have subsequently been replaced with MCBs.

[ARW]

So a fuse box not a CU?

[spuorgelgoog]

No, a consumer unit formerly fitted with fuses.

"Consumer Unit (may also be known as a consumer control unit). A particular type of distribution board comprising a type-tested co-ordinated assembly for the control and distribution of electrical energy, principally in domes tic premises, incorporating manual means of double-pole isolation on the in coming circuit(s) and an assembly of one or more fuses, circuit breakers, r esidual current operated devices or signalling and other devices proven dur ing the type-test of the assembly as suitable for use." IEE Wiring Regulations Seventeenth Edition - British Standard BS7671:2008, Part 2 Definitions (cited in wikipedia: consumer unit)

A fuse box would be a box with fuses in it, usually not having a switch.

Owain

[ARW]

No, a consumer unit formerly fitted with fuses.

"Consumer Unit (may also be known as a consumer control unit). A particular type of distribution board comprising a type-tested co-ordinated assembly for the control and distribution of electrical energy, principally in domestic premises, incorporating manual means of double-pole isolation on the incoming circuit(s) and an assembly of one or more fuses, circuit breakers, residual current operated devices or signalling and other devices proven during the type-test of the assembly as suitable for use." IEE Wiring Regulations Seventeenth Edition - British Standard BS7671:2008, Part 2 Definitions (cited in wikipedia: consumer unit)

A fuse box would be a box with fuses in it, usually not having a switch.

That wiki article is a joke.

And there is little chance that a Wylex fuse box could be used to power a new shower installation due to the lack of RCD protection,

[Roger Mills]

Is there a difference? I thought that "Consumer Unit" was simply a fancy new name for "Fuse Box". I can't remember what it was called when I bought it - I *think* it was described an a CU but I can't swear to it.

AIUI, they both take an input from the meter and allow a number of individually protected circuits to be connected - using re-wirable fuses, cartridge fuses, MCBs, RCBOs, whatever. OK, modern ones now have dual RCDs and all sorts of fancy tat - but weren't they called CUs before all of that?

[Roger Mills]

I should have read that before posting my last post.

Well, whatever I've got certainly has a 2-pole isolator switch in addition to the fuses/breakers.

[Roger Mills]

Not under current regulations, anyway.

Interestingly, I had an extension built in 1994 which included an en-suite - and the original intention was to have an electric shower in the en-suite. So I had a circuit installed with 6mm (I think) cable - utilising this first slot in the CU. In the event, I ran a hot feed to the shower from the HW cylinder and only used this circuit for a shower pump - but it would otherwise have powered an electric shower without RCD protection - perfectly legally at that time as far as I am aware.

Whether or not I'd still have been here now is another matter!

[tabbypurr]

No. 2.25 lpm.

NT

[tabbypurr]

then I guess that's not what you want :) There are a few ways to reduce shower power with it still feeling good: aeration, pressure, drain heat exchanger.

NT

[Roger Mills]

That *is* a dribble! A decent shower needs at least 10 lpm.

[Tim+]

Drain heat exchanger?? To recover f*ck all heat from a 3kw shower? I trust you've costed this out and can point us all to a suitable device that's already available?

Tim

[Syd Rumpo]

I'm not so sure it's a bad idea. After all, the water is mostly falling on a warm body. Consider the difference between summer and winter in a

7kW shower.

You'd need some good active flow control to maintain a constant temperature, and you'd start off with a dribble before the heat exchanger started working. Perhaps also a proportion of the water could be recirculated as long as you don't have the habit of pissing in the shower.

But it's probably not worth it where power and water in shower quantities are cheap.

Cheers

[Tim+]

Oh in theory it may not be a bad idea BUT bear in mind the the "hot" water dribbling out of this 3kw shower will have given up most of its heat to the air before it ever hits the drains. If you can actually find a unit on sale in the UK you're a better googler than I. The only ones I could find don't seem to be on sale any more (I wonder why?) and mention a minimum flow of 5L/min.

As a way of improving a shower it must surely be *way* down the list of realistic options. One Dr Drivel would be proud of though.

Tim

[Ash Burton]

It has been normal installation practice in the UK for many years to have an On/Off switch on most *domestic* 'fuse boxes' even 1 way units.

--- news://freenews.netfront.net/ - complaints: [e-mail] ---

[Syd Rumpo]

I think normally most of the heat is given up to the tray. Certainly your feet still get warm water some 2m from the shower head, in any case your body is around 37C.

I did look a few years ago in case it was patentable, and found a granted US patent but no commercial units made.

Just not worth it - a few kW for a few minutes is a few pence, and the flow control would be quite complex with the fairly rapidly changing input temperature.

Cheers

[tabbypurr]

There's most of 3kW in it.

I did a few years ago, and concluded it was worth doing, but its never got to the top of my to do list so far.

No, its roll it yourself territory. They're widely used in industry, but not domestically. Its only plumbing.

NT