shower problems wrong wiring...?

jetlagged

okay well I was swapping a T90 aquasensation electric shower out today for a bigger t90, 8.5kw, evrything was fine until I saw the cabling coming down the wall in conduit with what looked like 1.5 square cable. So I went up to the attic and sure enough the cabling is 1.5. Now the old shower was working fine and the reason it was changed was the pump was shagged. So rather than go making a big mess at 4 oclock on a friday I hooked up the 1.5 into the 8.5kw t90. Its working perfectly. Now my question is..I know it should be a minimum of 6mm2 cable..will the 1.5 melt? I was told that a 'certified electrician' installed it like that. From the fusebox I worked out its being fed from the sockets mcb. Am I in trouble? do I need to undo what i did?

bertie1

An 8.5kw shower is running arond 35 amps. You should have it wired in 6 sq T+E minimum and put a seperate RCBO or an mcb & rcd on 40 A and a pull chord switch to isolate it for maintenance ( 40 or 50 Amp.) If there is another electric shower in the house you will need to put in a priority unit as well ( so that only one can run at any time )

fishdog

Am I in trouble?

Yes. Big sh!t Tonto!

bertie1 is correct.

will the 1.5 melt?

There is a very good chance of that.

I dont care wired shower what you have is very dangerous. If I were you I would turn it off at the board straight away and do not use it again until it is installed correctly.

If that arrangement was safe we would all be doing it saving ourselves a fortune.

RoundyMooney

+1.

The following is not intended as a suggestion that smaller cabling is safe in any application...

I have seen 1.5 tails in some places feeding an entire dwelling, shower, cooker, sacred heart lamp and all :eek:

No signs of stress on it, probably due to the fact that the runs were so short.

jasonos

yeah best not use that shower again until u have upgraded your cable to 10square twin and earth.
if u run that shower the 1.5 cable will melt in your attic and burn the house down

what size is the mcb feeding it at the moment
its bad wiring if its anything over 10amps

fishdog

what size is the mcb feeding it at the moment
its bad wiring if its anything over 10amps

We know that the rating of the MCB/fuse is well over 10 amps, or the shower would never have operated. Bear in mind the poster has told us it is rated at 8.5 KW.

yeah best not use that shower again until u have upgraded your cable to 10square twin and earth.

In most cases a 6 square T&E is adaquate for an 8.5Kw load, unless the cable run is very long or a C type MCB is used instead of a B type.

Remember you need to have an instantanious shower protected by its own RCD.

As RoundyMooney has pointed out you will see the most dangerous things done electricaly. Somehow some of these efforts defy the laws of physics and work without killing anyone where as other times they have terrible consequences.

Just because the 1.5 cable worked in the past means nothing. I will bet I could wire some mains voltage lights with wet pieces of string, and they would work and possibly for longer than anyone would expect (please do not try this at home).

DublinDilbert

RoundyMooney wrote: »

+1.

The following is not intended as a suggestion that smaller cabling is safe in any application...

I have seen 1.5 tails in some places feeding an entire dwelling, shower, cooker, sacred heart lamp and all :eek:

No signs of stress on it, probably due to the fact that the runs were so short.

I once saw 2 live rails jumper-ed in a fuse board with 1.5 cable, and like that there was a cooker + a load of socket circuits running off if the rail that was jumpered...

All i can think of was that the jumper was very short, about 6 inches so the live rails either side would of worked like heat sinks taking the excessive heat away from the cable.

davelerave

a goed few people have been killed using electric showers with faulty wiring and leads i heard of two anyway .one local where they used a temporary lead that melted .not so much now i think .the reci inspector used to be on about them all the time

jetlagged

Yeah I havent heard anything but i hope nothings melted. Going back over today to shut the shower off, they have another one so its grand. The thing is its a really tough run back to the fusebox. Im gonna bring 6mm2 t+e back to the fuseboard and into a 40 amp rcd. Theres already one of these feeding the other shower so i will take the feed off that. Wont this lead to problems?
Now heres the thing, they asked for an electric shower, the old one was an electric mixer shower, which means it was fed hot and cold water and just regulated the temperature, whereas the new one has the thermostat job to heat the cold water up. Im thinking it would be alot easier to convince them to just get a mixer shower and pump maybe. I have no idea what kw rating the old one was, im just trying to understand why an electrician would have used 1.5kw.

Stoner

OP I'm sure this is in line with most of the advice you are getting here, you can't feed two showers from the one RCBO you will need a shower connection joint unit, this will allow only one to operate at any one time, available from most of the suppliers listed in the sticky above.

Also with the lenght of run a 10sq.T+E would be better for an electric pump shower

Replacing the mixer shower, where the heating system does all the work is the way to go IMO, you wont need such a huge cable then, i would say that it was always meant to be a mixer shower and that is the reson the smaller cable was used

fishdog

jetlagged

With the type of questions you are asking it is clear to me that you do not have the experience or training to take on this job and be sure that it is 100%safe.

My advice is to get a qualified electrician to do the job and ultimatley be responsible for it.

As davelerave pointed out:

a goed few people have been killed using electric showers with faulty wiring and leads i heard of two anyway

You really need to know what you are doing or you may be responsible for getting someone killed just so you can save a few bob. Is it worth it????

Now heres the thing, they asked for an electric shower, the old one was an electric mixer shower, which means it was fed hot and cold water and just regulated the temperature

This would make me think that the original shower was not a T90. A T90 does not have a hot and cold water feed, it just has a cold water feed. I would guess that this shower did not heat the water, so it may have been drawing less than 2KW, so OK with a 1.5 sq. cable.

jonnner

You really have done something extremely dangerous here and should think again before undertaking any electrical work.
As people have mentioned, electric showers can be extremely dangerous.
The best solution now is probably to install a mixer shower. The 1.5mm cable may be sufficient for a mixer shower but check KW rating 1st.

jetlagged

Well as I said before I thought I was doing a straight swap. I disconnected the shower today and explained the situation to them. Just to clear up, I wouldnt go messing with the likes of this usually. and if I was going to bring the 10 square back to the board thats where my work would end.
Gonna try and organise a new pumped mixer shower that will work off the 1.5, and I'll inspect the cable to make sure there wasnt any damage done.
Thanks for the replies on this, they were very important!!

Hopr

jetlagged wrote: »

okay well I was swapping a T90 aquasensation electric shower out today for a bigger t90, 8.5kw, evrything was fine until I saw the cabling coming down the wall in conduit with what looked like 1.5 square cable. So I went up to the attic and sure enough the cabling is 1.5. Now the old shower was working fine and the reason it was changed was the pump was shagged. So rather than go making a big mess at 4 oclock on a friday I hooked up the 1.5 into the 8.5kw t90. Its working perfectly. Now my question is..I know it should be a minimum of 6mm2 cable..will the 1.5 melt? I was told that a 'certified electrician' installed it like that. From the fusebox I worked out its being fed from the sockets mcb. Am I in trouble? do I need to undo what i did?

Jettlagged,

I know this post is a week old but hopefully you have disconnected the Triton T 90.The original shower you were replacing sounds like it is an Aquasensation AS2000x(t).

This is a mixer shower which draws both hot and cold from the water supplies and has a pump to boost flow rates.This particular shower needs to be protected by a 30mA rcbo 6A/10A and a isolation switch fused at 3A.The Original wiring seems to be correct (for the aquasensation) however when you connected the T90 in theory the protection should have tripped and/or blown 3a fuse in isolation switch (fused spur).The fused spur may still have a 13A fuse in it and the mcb is say 20A, this may not have blown if the T90 did not draw its full load.

The T90 (8.5Kw)can draw up to 38A and should be protected by 30mA rcbo 40A and isolation switch as pointed out by other posters.Also the earthing of the installtion should be checked and up to the standards set out in the ETCI regs (earth rod,earthing,bonding etc).

It would seem to be easier to just replace the offending pump.Any of the major hardware stores should be able to source this pump.Get the original installation checked by quailified electrician.

Here is a link for Triton http://www.tritonshowers.co.uk.Earthridge in Maynooth are distributors in Eire (open for correction) and Chadwicks hardware are agents and can source spare parts.Contact a Triton repair technician.

Bruthal

RoundyMooney wrote: »

+1.

The following is not intended as a suggestion that smaller cabling is safe in any application...

I have seen 1.5 tails in some places feeding an entire dwelling, shower, cooker, sacred heart lamp and all :eek:

No signs of stress on it, probably due to the fact that the runs were so short.

Yes the 1.5 will take a lot more than would be thought, and short runs only mean the load is kept to getting close to the 230v required. If the length of run is longer, the load will get a lower voltage as more is dropped across the overloaded 1.5, but the 1.5 would`t usually get any hotter if the run is longer on a given load. If its lenght is doubled, then it will have twice the voltage dropped along the cable, and so double the wattage of heat given off, but it has double the length to dissipate the heat. So the temp remains more or less the same, but a heavy load does`t get the proper voltage

A shower on 15 meter run of 1.5 probably would`t work very well, if the cable is about 0.25 ohms per 15 meters then 0.5 ohms total, 9kw is about 6 ohms. So current flow for 9kw at 230 should be 39.1 amps, but will be 230/6.5 ohms = 35 amps because of higher 1.5 cable resistance.
So shower kw is (I squared x R)35x35x6=7.35kw. Cable power dissipation = 0.5x35x35=612 watts

Voltage at shower is 6 ohms x 35A = 210v

So the shower is reduced from 9kw`s on a propper size cable to 7.35kw which is a drastic drop in performance. 600 watts along the cables length wont melt it, but it certainly would`t be regarded as safe either with 40amp breaker protecting it and 35 amps flowing in it.

Its also harder to get good enough connections for that load on a smaller cable, and its at connections the real danger of burning is present.

No competent electrician would ever use 1.5 on anything like a shower, or from a breaker any bigger than 10 amps

.G.

jetlagged wrote: »

okay well I was swapping a T90 aquasensation electric shower out today for a bigger t90, 8.5kw, evrything was fine until I saw the cabling coming down the wall in conduit with what looked like 1.5 square cable. So I went up to the attic and sure enough the cabling is 1.5. Now the old shower was working fine and the reason it was changed was the pump was shagged. So rather than go making a big mess at 4 oclock on a friday I hooked up the 1.5 into the 8.5kw t90. Its working perfectly. Now my question is..I know it should be a minimum of 6mm2 cable..will the 1.5 melt? I was told that a 'certified electrician' installed it like that. From the fusebox I worked out its being fed from the sockets mcb. Am I in trouble? do I need to undo what i did?

Jesus wept:rolleyes:

Given the date of this post I know its a bit late for this but as far I'm concerned the person who lasts works on an installation or circuit is the one who's responsible for its safety or otherwise and I'm pretty sure the law would see it that way too.

Regardless of how it was wired originally if you know its wrong and you leave it then your to blame if something happens.

sadly you really do see all sorts in this game.

Meter tails made from cat 5 bunched together.My friends instructor in college showed him a photo of exactly that.
The mind boggles.

aujopimur

It's obvious, you have replaced a power shower with an instantaneous electric shower, your power consumption has increased from 10 amps. to 45 amps (approx).

dolittle

Meter tails made from cat 5 bunched together.My friends instructor in college showed him a photo of exactly that.
The mind boggles.[/QUOTE]

unbelievable....cat 6 would be much safer