pajsh
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| posted on 29/9/07 at 04:54 PM |
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Any Electicians That Can Help??
I've got a problem with our electric shower buzzing.
Took it apart and the red live into the terminal block was blackened and the insulation partly melted. The centre of the terminal block is also
showing signs of heat damage.
Obviously not good and my first thoughts are bad connection and sparking at the terminal block.
I've cut the wires back to some good bare copper and screwed it up as tight as I can to get a good contact but I'm still concerned as to
why it is getting so hot.
Shower is 8.5 kW on a fairly shortish run (5m) of 6mm˛ cable.
I seem to remember only going for a 8.5 kW as I thought the cable would not take anything greater.
Anyone any ideas what is causing it to buzz/spark/overheat??
I used to be apathetic but now I just don't care.
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MkIndy7
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| posted on 29/9/07 at 05:13 PM |
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You have replaced the terminal block that was looking a bit black haven't you  and not just tightned it up.
And the wire will have been damaged a good 1" back I would have though, you want to get all the way back to the nice shiney stuff, not where its
still dull.
The only other thing you could do if you've got the correct type of Industrial multimeter (the kind that goes either side of the cable or a
clamp meter) and load test the eliment and check its not taking too much current.
Has there been anyother indications thats its going faulty?... water not always warm, differeing temperatures, discoloured water etc
Wires can burn out due to loose/faulty connections, vibration over time, heat, or in this case maybe that the eliment is drawing slightly too much
current over a period of time or "overloading" as apposed to a big short or fault that would blow the fuse.
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nitram38
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| posted on 29/9/07 at 05:25 PM |
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To start with I am an Electrician so I come across these things a lot.
What you describe is almost certainly caused by arcing due to a loose terminal.
As said before, replace the block and clean the cable etc and just make sure it is tight.
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Macbeast
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| posted on 29/9/07 at 07:16 PM |
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Be aware that it could also be a bad connection on the other side of the terminal block (where the juice goes off to the element) so tightening up the
red wire may not be effective.
I had a 13A domestic outlet get very hot. Nothing wrong with wires going into the terminals - must have been bad internal connection.
As above - you MUST replace the terminal block.
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Bigheppy
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| posted on 29/9/07 at 08:20 PM |
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check the shower instructions I think that 8kw needs 10mm cross sectional cable
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MkIndy7
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| posted on 29/9/07 at 08:32 PM |
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Just found this.. very useful
http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
It says 6mm should be fine, but might be worth saving for future use by some people.
But if the Regs are anything like gas the manufacturers instructions are always FINAL!
[Edited on 29/9/07 by MkIndy7]
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pajsh
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| posted on 29/9/07 at 10:01 PM |
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Great link for future ref.
Thanks for the advice guys. Trip to B&Q tomorrow for a terminal block to make sure it is all OK.
We have had a shower in the same spot for 5 years but this one is only a year old and having just been "fixed" under warranty it has only
recently started buzzing.
Least I know all the facts now.
Thanks again all.
I used to be apathetic but now I just don't care.
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tks
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| posted on 30/9/07 at 04:17 PM |
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8kw!!
wtf kind of shower is that? any pics??
Tks
The above comments are always meant to be from the above persons perspective.
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JoelP
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| posted on 30/9/07 at 05:04 PM |
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showers here vary between 8 and 10.5kw typically, so its a common rating. What rating are electric showers in spain? Or is it warm enough to shower
cold?! 
8.5kW will draw 34A at 250V, and i see a lot of houses that arent far off 250.
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tks
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| posted on 30/9/07 at 05:22 PM |
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warm water comes from gas here...i'm now in the NL btw and here its same practise....
or we have a boiler but its never 8,5KW of electric energie!
Tks
The above comments are always meant to be from the above persons perspective.
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JoelP
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| posted on 30/9/07 at 07:14 PM |
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its better to have a shower off the boiler as you say. In fact, i dont know why people use electric showers tbh, but they are quite common. I guess
some houses dont have a boiler big enough for a shower flow.
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Macbeast
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| posted on 30/9/07 at 07:54 PM |
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These are instant heat electric showers, turn the tap and instant hot water, hence the 8.5KW.
I have one in my apartment because there's no room for a boiler.
Image deleted by owner
[Edited on 30/9/07 by Macbeast]
oops!! Must clean that shower head 
[Edited on 30/9/07 by Macbeast]
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MkIndy7
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| posted on 30/9/07 at 08:03 PM |
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Energy wise whats wrong with electric showers?.
Electricity prices were the main reason a boiler was prefered,
Surely 8.5kw is 8.5 Kw wherever its coming from. Infact an electric shower may even be more efficient way heating the water.
It can't be that in-efficient and the prices must be equaling out as they have now started selling Electic heating boilers!. (more than likely
for landlords so they will no longer require landlord certificates every year for the boiler.. and the tennants pay the electricity bill anyway!)
There also probably never really heard of abroard as 8.5Kw at 110V would be alot of amps! (there was sombody on here a while back about how long a
kettle took to boil abroard.. and thats only 3Kw)
My 2 penneth
[Edited on 30/9/07 by MkIndy7]
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tks
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| posted on 1/10/07 at 08:44 AM |
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We are at 220/240 in Spain and NL
a boiler is really wel packed up!
in fact its like fridge...it consumes not much power ands keeps the water warm.
we at home have a boiler that when its empty it can instantly generate hot water but i guess its 3KW not 8,5!
anyway there don't run 6mm2 cables up stairs sow must be something reasonable....
does it has steam options or anykind?
Tks
The above comments are always meant to be from the above persons perspective.
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MkIndy7
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| posted on 1/10/07 at 05:08 PM |
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Not quite steam!.
They are such a high Kw rating as they warm the water up instantly as it passes through the shower.
I think the typical UK (possibly all over the world) incoming water temerature is 10 DegC so to warm that upto 50-60 degrees instantly takes alot of
energy.
"we at home have a boiler that when its empty it can instantly generate hot water but i guess its 3KW not 8,5!"
That is the equivalent of boiling the kettle, it warms the water up in about 2-3 mins but in nowhere near the volume and flow rate required to feed a
shower.
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pajsh
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| posted on 5/10/07 at 08:12 AM |
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Main reasons for an electric shower are:
1) Simplicity - only one cold service rather than two.
2) Lack of head - uses mains pressure rather than from the header tank.
3) On demand supply compared with stored water.
I did recently consider changing but ruled out the other options as:
1) Power shower - works from stored hot water which is no good for us as 4 people want showers in the morning and the hot water would run out.
2) Combi boiler - Better but as the boiler is heating water for the shower it does not heat the rads so again not ideal if 4 people have showers in
the morning and we have no heating for 3/4 hr.
Down side of electric showers are I guess they are not that cheap to run and not as powerful as pumped systems.
I used to be apathetic but now I just don't care.
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chockymonster
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| posted on 5/10/07 at 08:28 AM |
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quote:
Originally posted by pajsh
Down side of electric showers are I guess they are not that cheap to run and not as powerful as pumped systems.
But when someone turns on the hot tap you don't get freezing cold water
It's also a godsend if your boiler breaks.
PLEASE NOTE - Responses on Forum Threads may contain Sarcasm and may not be suitable for the hard of Thinking.
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